Van Tran v. State 66 S.W.3d 790

OPINION

E. RILEY ANDERSON, J.,

delivered the opinion of the court, in which

FRANK F. DROWOTA, III, C.J., and ADOLPHO A. BIRCH, JR., join.

We granted this appeal to determine whether the trial court and the Court of Criminal Appeals erred by denying the petitioner’s motion to reopen his post-conviction petition. In his motion, the petitioner asserted that new evidence establishes that he is mentally retarded and, therefore, ineligible for the death penalty under TenmCdde Ann. § 39-13-203, which prohibits the execution of the mentally retarded. The petitioner also argued on appeal that the Eighth Amendment to the United States Constitution and article I, § 16 of the Tennessee Constitution prohibit the execution of mentally retarded individuals.

After careful consideration, we conclude that the General Assembly did not clearly intend to apply Tenn.Code Ann. § 39 — 13— 203 retroactively and that the statute therefore provides no basis to reopen a post-conviction suit for a petitioner who was sentenced before its effective date. We also conclude, however, that the Eighth Amendment to the United States Constitution and article I, § 16 of the Tennessee Constitution prohibit the execution of mentally retarded individuals because such executions violate evolving standards of decency that mark the progress of a maturing society, are grossly disproportionate, and serve no valid penological purpose in any case. We therefore reverse the judgment of the Court of Criminal Appeals and remand the case to the trial court for farther proceedings.

Background

In 1989 the petitioner, Heck Van Tran, was convicted of three counts of felony murder and sentenced to death on each count for his role in killing three people during a robbery at a Memphis restaurant. On appeal, this Court affirmed all three of the murder convictions and one of the death sentences. State v. Van Tran, 864 S.W.2d 465 (Tenn.1993).1

*793While this case was pending on direct appeal, the General Assembly enacted Tenn.Code Ann. § 39-18-203 (1991), which provided in part as follows:

(a) As used in this section, “mental retardation” means:

(1) Significantly subaverage general intellectual functioning as evidenced by a functional intelligence quotient (I.Q.) of seventy (70) or below;

(2) Deficits in adaptive behavior; and

(3) The mental retardation must have been manifested during the developmental period, or by eighteen (18) years of age.

(b) Notwithstanding any provision of law to the contrary, no defendant with mental retardation at the time of committing first degree murder shall be sentenced to death.

(c) The burden of production and persuasion to demonstrate mental retardation by a preponderance of the evidence is upon the defendant. The determination of whether the defendant was mentally retarded at the time of the offense of first degree murder shall be made by the court.

(e) If the issue of mental retardation is raised at trial and the court determines that the defendant is not a person with mental retardation, the defendant shall be entitled to offer evidence to the trier of fact of diminished intellectual capacity as a mitigating circumstance pursuant to § 39 — 13—204(j)(8).

This statute became effective on July I, 1990.2

On March 7, 1995, Van Tran filed a petition seeking post-conviction relief that relied in part upon this statute as a basis for setting aside his sentence of death. An evidentiary hearing was conducted in October of 1997. Prior to this hearing, Dr. Andrew J. Adler, a licensed psychologist, tested petitioner using the Wechsler Adult Intelligence Scale Revised (“WAIS-R”)3 and a Vineland Adaptive Behavior Scale. Dr. Adler testified at the post-conviction hearing in 1997 that petitioner had a full scale I.Q. of 67 and that he had deficits in adaptive behavior that had manifested during the developmental period before the age of eighteen (18). Dr. Adler concluded that the petitioner was mentally retarded as defined by Tenn.Code Ann. § 39-13-203(a).

Dr. Lynn Zager, a psychologist called as a witness by the State, testified that the petitioner’s I.Q. was actually 72 with a standard error measurement of plus or minus three, rather than 67 as testified by Dr. Adler. Dr. Zager testified that Dr. Adler had made a clerical error in applying the conversion chart. The trial court credited Dr. Zager’s testimony and dismissed the petition for post-conviction relief. The dismissal was affirmed both by the Court *794of Criminal Appeals and by this Court without addressing the statutory or constitutional issue of executing a mentally retarded defendant. See Van Tran v. State, No. 02C01-9803-CR-00078, 1999 WL 177560, at *6 (Tenn.Crim.App. Apr. 1, 1999); Van Tran v. State, 6 S.W.3d 257 (Tenn.1999).

In December of 1999, Dr. Adler again tested the petitioner’s I.Q., this time using the Wechsler Adult Intelligence Scale— Third- Edition (“WAIS-III”), an updated version of the WAIS-R. Dr. Adler determined that petitioner’s full-scale I.Q. is 65. Relying upon this data, petitioner filed a motion on February 7, 2000 seeking to reopen his previous post-conviction petition pursuant to Tenn.Code Ann. § 40-30-217 (1997), which provides in pertinent part:

(a) A petitioner may file a motion in the trial court to reopen the first post-conviction petition only if the following applies:

(1) The claim in the motion is based upon a final ruling of an appellate court establishing a constitutional right that was not recognized as existing at the time of trial, if retrospective application of that right is required. Such motion must be filed within one (1) year of the ruling of the highest state appellate court or the United States supreme court establishing a constitutional right that was not recognized as existing at the time of trial; or

(2) The claim in the motion is based upon new scientific evidence establishing that such petitioner is actually innocent of the offense or offenses for which the petitioner was convicted; or

(4) It appears that the facts underlying the claim, if true, would establish by clear and convincing evidence that the petitioner is entitled to have the conviction set aside or the sentence reduced.

The motion was accompanied by an affidavit from Dr. Adler stating both the results of the WAIS-III and Dr. Adler’s conclusion that the petitioner is mentally retarded as defined by Tenn.Code Ann. § 39-13-203(a).

The trial court issued a preliminary order denying the petitioner’s motion to reopen, and the Court of Criminal Appeals denied the petitioner’s application for permission to appeal. Thereafter, the petitioner filed an application for permission to appeal which this Court granted. Following oral argument, this Court entered a unanimous order directing the parties to file supplemental briefs addressing an issue of first impression for this Court: whether the Eighth Amendment to the United States Constitution or article I, § 16 of the Tennessee Constitution prohibits executing a mentally retarded defendant. For the following reasons, we reverse the judgments of trial court and the Court of Criminal Appeals and remand the case to the trial court for further proceedings.

Menial Retardation

Although the statutory definition of mental retardation in Tennessee adopts the nationally accepted definition of mental retardation, see Penny v. Lynaugh, 492 U.S. 302, 308 n. 1, 109 S.Ct. 2934, 2941 n. 1, 106 L.Ed.2d 256 (1989), no commentary or background is provided on the nature of mental retardation. As one writer has observed, “mental retardation is a debilitating mental defect that is understood by few and accepted by even fewer.” Juliet L. Ream, Capital Punishment for Mentally Retarded Offenders: Is it Morally and Constitutionally Impermissible?, 19 Sw. U.L.Rev. 89, 106 (1990). To provide some understanding and context, we will briefly *795discuss the general characteristics and background of mental retardation before turning to the precise issues in this case.

The Diagnostic and Statistical Manual of Mental Disorders (DSM IV)4 defines a mentally retarded person as one who has “significantly subaverage general intellectual functioning” accompanied by “significant limitations in adaptive functioning in at least two of the following skill areas: communication, self-care, home living, social/ interpersonal skills, use of community resources, self-direction, functional academic skills, work, leisure, health, and safety.” American Psychiatric Association, Diagnostic and Statistical Manual of Mental Disorders, 39 (4th ed.1994). Like the statutory definition, the DSM-IV requires that the intellectual and adaptive deficits manifest themselves by the time the person is eighteen years of age. Id.

The first part of the definition — subaver-age general intellectual functioning — is based on Intelligence Quotient (“I.Q.”) scores that are obtained through the use of standardized intelligence tests. The DSM IV uses the following scales:

IQ of 50-55 to approximately 70: mild mental retardation

IQ of 35-40 to 50-55: moderate mental retardation

IQ of 20-25 to 35-40: severe mental retardation [and]

IQ below 20-25: profound mental retardation.

Id. at 40. To put these scales into a broader context, the DSM-IV states that mental retardation has a prevalence rate of about one percent of the population. Of this one percent, eighty-five percent are mildly retarded; ten percent are moderately retarded; three to four percent are severely retarded; and one to two percent are profoundly retarded. See id. at 41-42.

The second part of the definition— adaptive functioning — “refers to how effectively individuals cope with common life demands and how well they meet the standards of personal independence expected of someone in their particular age group, socio-cultural background, and community setting.” Id. at 40. As discussed, a mentally retarded person will have significant limitations in at least two of the following basic skills: “communication, self-care, home living, soeial/interpersonal skills, use of community resources, self-direction, functional academic skills, work, leisure, health, and safety.” Id. at 39. Influences on adaptive functioning may include the individual’s “education, motivation, personality characteristics, social and vocational opportunities, and the mental disorders and general medical conditions that may coexist with Mental Retardation.” Id. at 40.

Despite the various classifications and wide range of factors, the DSM IV makes it crystal clear that all mentally retarded individuals bear substantial limitations in both intelligence and functioning.5 All *796persons with mild mental retardation may attain academic skills up to only the sixth grade level, but some may attain various levels of life and work skills with supervision and support. Id. at 41. A person with moderate mental retardation may learn to attend to self-care and perform basic work skills under supervision, yet can attain academic skills up to only the second grade level. Id. A person with severe mental retardation may learn to talk and may be trained in elementary self-care skills with supervision. Id. Finally, a person with profound mental retardation displays significant impairments and requires constant care in a highly structured and supervised environment. Id. at 41-42.

There are, therefore, varying degrees of mental retardation, yet each is by definition marked by significant and serious impairments to intelligence and adaptive functioning. As one commentator has said, “The[] labels [of mental retardation] should be cautiously applied ... because they may be misleading — mildly retarded people are substantially disabled, but only mildly so when compared to other [mentally retarded people].” Capital Punishment for Mentally Retarded Offenders, 19 Sw. U.L.Rev. at 107 (emphasis added).

As we examine the nature and characteristics of mental retardation, we find it striking that the substantial impairments of all mentally retarded individuals outlined above are largely ignored in the dissenting opinion. Indeed the premise of the dissent is that the “mere fact” of mental retardation warrants no constitutional consideration unless accompanied by a cognitive, moral, or volitional incapacity such as the inability to distinguish right from wrong, understand the nature of one’s actions, or conform one’s conduct to the requirements of law. The dissent offers no controlling or persuasive Tennessee authority for its analysis of mental retardation and its effects; indeed, neither the nationally recognized definition of mental retardation nor the statute enacted by the Tennessee legislature contains the cognitive, moral, or volitional components argued by the dissent.

Instead, the dissent argues that State v. Laney, 654 S.W.2d 383 (Tenn.1983), is dis-positive of the constitutional issue in this case. The defendant in Laney, however, had an I.Q. over 70 and argued only that the execution of a person with “low intelligence” was cruel and unusual punishment. Moreover, Laney was decided prior to the passage of Tenn.Code Ann. § 39-13-203 (1991). Accordingly, even a cursory review of Laney reveals that this Court did not address mental retardation, its implications, or the constitutionality of executing mentally retarded defendants under article I, § 16 of the Tennessee Constitution.

Moreover, the dissent’s analysis would, in numerous instances, effectively require the mentally retarded offender to all but establish an affirmative defense of legal insanity in order to avoid the death penalty. See Tenn.Code Ann. § 39-ll-501(a) (1997). This argument avoids the constitutional issue in this case given the fact that the legally insane are already constitutionally protected from execution. See Van Tran v. State, 6 S.W.3d at 262. Accordingly, we undertake our review while bearing in mind the nationally recognized fact that every person who is mentally retarded has significant and serious impairments to intelligence and everyday functioning.

Retroactive Application

Given this background and understanding of mental retardation, it is hardly surprising that in 1990 the Tennessee legislature enacted legislation to prohibit the execution of mentally retarded persons. See Tenn.Code Ann. § 39-13-203 (1991). *797Eighteen other jurisdictions have also prohibited such executions by statute.6 A threshold issue in this case is whether the Tennessee statute prohibiting imposition of a death sentence upon persons who are mentally retarded applies retroactively to mentally retarded prisoners who had been sentenced to death in Tennessee before July 1, 1990, the effective date of the statute.

The petitioner asserts that the General Assembly did intend for the statute to be retroactively applied and that this intent is implicit in subsection (b) of the statute stating that it applies “notwithstanding any provision of law to the contrary.” Furthermore, the petitioner argues that this Court should apply the rule of leniency, which mandates that any ambiguity be resolved by construing a statute in favor of the defendant. Since his case was pending on appeal on July 1, 1990, the effective date of the statute, the petitioner contends that, both as a matter of policy and by analogy to constitutional rules that are applied to cases still in the appellate process when the rule is announced, this new, “remedial” statute should be retroactively applied to his case.

The State responds, however, that the General Assembly did not intend to give retroactive application to Tenn.Code Ann. § 39-13-203 because the statute provided only an effective date of July 1, 1990, and it contained no other specific language requiring retroactive application.7 The State relies upon the general rule of statutory construction which provides that statutes are to be applied prospectively in the absence of clear legislative intent to the contrary. Citing numerous Public Acts, the State argues that when the General Assembly intends to apply a statute retroactively, specific language indicating this intent is included in the statute.8

The State also notes that the express language of the statute governed only future sentencing hearings, ie., “no defendant with mental retardation at the time of committing first degree murder shall be sentenced to death.” Tenn. Code Ann. § 39-13-203(b) (1991). The State contends that this language is a clear expression of the General Assembly’s intent that the statute apply only to sentencing hearings occurring after its effective date of July 1, 1990. According to the State, the General Assembly expressed its intent that the statute apply prospectively by failing to include a method by which persons already sentenced to death could raise the issue of mental retardation.

We agree that it is a well-settled rule that statutes are to be applied prospectively in the absence of clear legisla*798tive intent to the contrary. See, e.g., State v. Cauthern, 967 S.W.2d 726 (Tenn.1998). With respect to the specific Tennessee mental retardation statute, we also agree with the State that there is no express language indicating that it must be given retroactive application. The General Assembly included only an effective date of July 1, 1990, with no language requiring the statute to be applied to death sentences imposed before that date. Moreover, the statute does not contain a procedure by which mentally retarded persons sentenced to death before July 1,1990, can raise mental retardation as a bar to execution, nor does it mention post-conviction proceedings as an avenue for challenging a death sentence on the basis of mental retardation.9

On the other hand, the petitioner correctly points out that the statute contained language making it applicable “notwithstanding any provision of law to the contrary.” See Tenn. Code Ann. § 39-13-203(b) (1991). In our view, this broad, ambiguous language warrants examination of the legislative history of the statute to determine legislative intent. Notably, during Senate debates on the bill, an amendment was offered to explicitly provide that the statute apply only to persons who committed first degree murder after its effective date. That amendment met with disapproval and was withdrawn without a formal vote. One Senator spoke strongly against the amendment:

Why have this amendment? If we are going to establish a state policy that what we have done in times past is wrong and that from a certain date we’re going to correct our error, I just don’t understand that. I understand that ... maybe we want to hold costs down, but I don’t understand how that balances with the importance of this bill, and I don’t think we ought to adopt this amendment. If what we’re doing here is right, and I think it is right, then it ought to be the right for everybody and not some people cut off by a certain date in time.

Tenn. S., Debate on H.B. 2107 on the Floor of the Senate, 96th Gen. Assembly, 2nd Reg. Sess. (Apr. 12, 1990) (Tape S-106B) (Substituted for S.B. 1851) (remarks of Sen. Lewis). The legislature’s failure to clearly provide for retroactive operation may have been a product of oversight or may have been based on the assumption that no prisoner then on death row was mentally retarded. See Tenn. H.R., Debate on Tenn. H.B. 2107 on the Floor of the House, 96th Gen. Assembly, 2nd Reg. Sess. (Apr. 5, 1990) (Tape H-62) (remarks of Rep. Jackson) (stating, in response to a question, that there were no mentally retarded inmates on Tennessee’s death row at that time).

In any event, although the issue as to retroactive application of the statute is close, we conclude that the absence of express language providing for retroactive application supports the conclusion that the legislature did not expressly intend such an application. As the State contends, other Public Acts demonstrate that when retroactive application is intended, the General Assembly includes specific, clear language expressing its intent. Such clear language is absent from Tenn.Code Ann. § 39-13-203. In short, notwithstanding the presence of some ambiguous language in the statute and in the legislative history, there is no evidence of a clear legislative intent to apply the statute retroactively as required by the general rule. *799We therefore conclude that the trial court and Court of Criminal Appeals properly-denied the petitioner’s motion to reopen on this ground. See Tenn.Code Ann. § 40-30 — 217(a)(2) (1997).

Constitutional Principles

We next turn to the argument that the execution of mentally retarded persons constitutes cruel and unusual punishment in violation of the Eighth Amendment to the United States Constitution and article I, § 16 of the Tennessee Constitution. Although the argument was not expressly set out in the defendant’s motion to reopen, we ordered the parties to file supplemental briefs on this constitutional issue because it is uniquely intertwined with the statutory issue and the critical, overriding question of whether a defendant who is mentally retarded may legally be executed in this State.

Although the Court was unanimous in its determination to reach this critical constitutional issue, and the State has not objected, the dissent now argues that the issue should be avoided.10 The dissent’s arguments are misplaced. A motion to reopen, by definition, is based on a new legal issue or new scientific evidence of actual innocence that serves as a new basis to “reopen” the earlier post-conviction proceeding. Tenn.Code Ann. § 40-30-217(a) (1997). Having identified that the unique but narrow circumstances of this case raise serious constitutional implications of first impression, a majority of this Court has decided to address these critical issues.11 As noted, the State has raised none of the procedural objections argued by the dissent and the parties have neither briefed nor argued them. As this Court has very recently said, “ ‘[T]he importance of correctly resolving constitutional issues suggests that constitutional issues should rarely be foreclosed by procedural technicalities.’ ” In re Adoption of E.N.R., 42 S.W.3d 26, 32 (Tenn.2001) (citation omitted).

We therefore begin our review of this issue by examining the relevant constitutional provisions. The Eighth Amendment provides that “[ejxcessive bail shall not be required, no excessive fines imposed, nor cruel and unusual punishments inflicted.” U.S. Const, amend. VIII. The language in article I, § 16 is nearly identical: “That excessive bail shall not be required, nor excessive fines imposed, nor cruel and unusual punishments inflicted.” Tenn. Const, art. I, § 16.

One of the first cases in which the United States Supreme Court analyzed the phrase “cruel and unusual punishment” was Weems v. United States, 217 U.S. 349, 30 S.Ct. 544, 54 L.Ed. 793 (1910). In holding that a sentence of 15 years of hard, enchained labor for the offense of falsification of a public document was cruel and unusual punishment, the Court said:

Time works changes, brings into existence new conditions and purposes. *800Therefore a principle, to be vital, must be capable of wider application than the mischief which gives it birth.

The [cruel and unusual punishments clause], in the opinion of learned commentators, may be therefore progressive, and is not fastened to the obsolete, but may acquire meaning as public opinion becomes enlightened by a humane justice.

Weems v. United States, 217 U.S. at 373, 378, 30 S.Ct. at 551, 553 (citations omitted). The Court later reaffirmed this analysis of the Eighth Amendment:

[T]he words of the Amendment are not precise, and ... their scope is not static. The Amendment must draw its meaning from the evolving standards of decency that mark the progress of a maturing society.

Trop v. Dulles, 356 U.S. 86, 100-01, 78 S.Ct. 590, 598, 2 L.Ed.2d 630 (1958) (emphasis added).

With these principles in mind, the United States Supreme Court has fashioned a three-prong analysis for determining whether a punishment constitutes cruel and unusual punishment under the Eighth Amendment:

First, does the punishment for the crime conform with contemporary standards of decency? Second, is the punishment grossly disproportionate to the offense?

Third, does the punishment go beyond what is necessary to accomplish any legitimate penological objective?

State v. Ramseur, 106 N.J. 123, 524 A.2d 188, 210 (1987) (citing Gregg v. Georgia, 428 U.S. 153, 173, 96 S.Ct. 2909, 2925, 49 L.Ed.2d 859 (1976)). This Court has applied the same analysis to determine whether a particular punishment constitutes cruel and unusual punishment under article I, § 16 of the Tennessee Constitution. See State v. Black, 815 S.W.2d 166, 189 (Tenn.1991). As explained below, we conclude that each of these factors supports the conclusion that executing the mentally retarded is cruel and unusual punishment under article I, § 16 of the Tennessee Constitution.12

As the State correctly observes, the United States Supreme Court held in 1989 that the execution of mentally retarded individuals is not per se precluded under the Eighth Amendment to the United States Constitution. See Penry v. Ly-naugh, 492 U.S. 302, 109 S.Ct. 2934, 106 L.Ed.2d 256 (1989). Because of the nature of the analysis and its consideration of contemporary values, however, it is unclear whether executing mentally retarded persons currently violates the Eighth Amendment. The United States Supreme Court has very recently granted certiorari to revisit its five to four Penry decision. See Daryl Renard Atkins v. Virginia, 533 U.S. 976, 122 S.Ct. 24, 150 L.Ed.2d 805 (2001).13

*801Moreover, irrespective of whether the United States Supreme Court adheres to or overrules Penry, it is axiomatic that this Court may extend greater protection under the Tennessee Constitution than is provided by the United States Supreme Court’s interpretations of the federal constitution. See State v. Black, 815 S.W.2d at 189. Accordingly, although we will refer to relevant analysis under the Eighth Amendment, all of our opinions and conclusions with respect to the execution of mentally retarded individuals — an issue of first impression for this Court — are separately and independently based upon article I, § 16 of the Tennessee Constitution.

Evolving Standards of Decency Nationally

The first of the factors set forth in Black, whether the punishment conforms with contemporary standards of decency, is arguably the most crucial. The United States Supreme Court emphasized in Pen-ry that “[t]he prohibitions of the Eighth Amendment are not limited ... to those practices condemned by the common law in 1789. The prohibition against cruel and unusual punishments also recognizes the ‘evolving standards of decency that mark the progress of a maturing society.’ ” Penry v. Lynaugh, 492 U.S. at 330-31, 109 S.Ct. at 2953 (citations omitted). Thus, if a punishment fails to conform with contemporary standards of decency, it is unconstitutional under the Eighth Amendment regardless of whether it satisfies the other factors of the analysis.

In defining contemporary standards of decency, a reviewing court must look to “objective evidence of how our society views a particular punishment today.” 492 U.S. at 331, 109 S.Ct. at 2953 (citations omitted). In Penry, the United States Supreme Court stressed that the “clearest and most reliable objective evidence of contemporary values is the legislation enacted by the country’s legislatures.” Id. When Penry was decided in 1989, only two states, Georgia and Maryland, had legislation prohibiting the execution of mentally retarded persons convicted of a capital offense. See 492 U.S. at 334, 109 S.Ct. at 2955. A majority of the Court concluded that these two states, even when added to the fourteen states that had no provisions for capital punishment, did “not provide sufficient evidence ... of a national consensus.” Id.

The Penry Court’s conclusion with regard to societal consensus based on state legislative action alone at the time was consistent with its analogous Eighth Amendment cases. In Ford v. Wain-might, for instance, the Court found a societal consensus against the execution of the insane where no state permitted such executions and twenty-six states had statutes suspending executions where a convicted defendant later became legally insane. 477 U.S. 399, 408 n. 2, 106 S.Ct. 2595, 2601 n. 2, 91 L.Ed.2d 335 (1986). In Thompson v. Oklahoma, a plurality indicated that a societal consensus against the execution of persons under the age of 16 existed where eighteen states had statutes requiring a minimum age of 16 at the time of the offense before execution. 487 U.S. 815, 829, 108 S.Ct. 2687, 2695, 101 L.Ed.2d 702 (1988); see also Tenn.Code Ann. § 37-l-134(a)(l) (2001) (a minor defendant under the age of 18 at the time of the offense who is transferred to criminal court for trial as an adult is not subject to the death penalty for that offense). In sum, the two *802states prohibiting execution of mentally retarded persons in 1989 did not create the consensus found by members of the Court in both Ford and Thompson.

It is immediately apparent, however, that the legislative landscape following Penry has undergone a dramatic transformation. Since the decision, no fewer than sixteen states — Arizona, Arkansas, Colorado, Connecticut, Florida, Indiana, Kansas, Kentucky, Missouri, Nebraska, New Mexico, New York, North Carolina, South Dakota, Tennessee, and Washington — have joined Georgia and Maryland in enacting legislation prohibiting the execution of mentally retarded individuals.14 The federal government likewise passed legislation prohibiting such executions.15

The majority of these jurisdictions enacted the legislation prohibiting the execution of mentally retarded persons following the Penry decision. Jonathan L. Bing, Protecting the Mentally Retarded From Capital Punishment: State Efforts Since Penry and Recommendations for the Future, 22 N.Y.U. Rev. L & Soc. Change 59, 116 (1996). Five states — Arizona, Connecticut, Florida, Missouri, and North Carolina — enacted the legislation after the United States Supreme Court indicated in McCarver v. North Carolina, 532 U.S. 941, 121 S.Ct. 1401, 149 L.Ed.2d 344 (2001), that it would reconsider Pem'y and the issue of whether a standard of decency marking a mature society has evolved against the execution of the mentally retarded. When these nineteen jurisdictions are considered along with the twelve states that do not have provisions for capital punishment, thirty-one jurisdictions now do not permit the execution of mentally retarded persons.

In addition to legislative enactments, other evidence supports the conclusion that execution of the mentally retarded is cruel and unusual punishment. The United States Supreme Court, for example, has identified “data concerning the actions of sentencing juries” as another relevant measure of contemporary standards of decency. Penry v. Lynaugh, 492 U.S. at 331, 109 S.Ct. at 2953. Although the data concerning capital jury sentencing tendencies is limited, the information available suggests that the punishment is no longer favored by jurors. The Capital Juror Project, a South Carolina jury study which this Court has relied upon in the past,16 found that jurors in capital cases attached “significant mitigating potential” to evidence that the defendant was mentally retarded. Stephen P. Garvey, Aggravation and Mitigation in Capital Cases: What do Jurors Think?, 98 Colum. L.Rev. 1538, 1539 (1998). In fact, “[ejvidence that the defendant was mentally retarded was almost as powerful as lingering doubt over *803his guilt,” with nearly 75 percent of the jurors surveyed, noting that evidence of mental retardation would make them less likely to vote for death. See id. at 1564. Although similar studies have not yet been conducted in Tennessee, the authors of the South Carolina study note that “the available data suggest [that] ... South Carolina jurors appear to think much like jurors from several other states taken in the aggregate.” Id. at 1540. Thus, though not conclusive, this study assuredly lends weight to the assertion that jurors view execution of the mentally retarded as repugnant to today’s standards of decency.

Moreover, other evidence that mentally retarded persons should not be executed abounds. The execution of the mentally retarded has been condemned by numerous professional organizations involved in the treatment of mentally retarded individuals, including the American Association on Mental Retardation, the Association for Retarded Citizens of the United States, the American Psychological Association, the Association for Persons with Severe Handicaps, the American Association of University Affiliated Programs for the Developmentally Disabled, the National Association of Private Residential Resources, the New York Association for Retarded Children, Inc., the National Association of Superintendents of Public Residential Facilities for the Mentally Retarded, the Mental Health Law Project, and the National Association of Protection and Advocacy Systems. See Lyn Entzer-oth, Putting the Mentally Retarded Criminal Defendant to Death: Charting the Development of a National Consensus to Exempt the Mentally Retarded from the Death Penalty, 52 Ala. L.Rev. 911, nn. 8, 9 (2001) (with accompanying text). The American Bar Association, which is composed of over 400,000 members representing a large cross-section of the modern legal community, also opposes the execution of the mentally retarded. See generally Carol Steiker and Jordan Steiker, Defending Categorical Exemptions to the Death Penalty: Reflections on the ABA’s Resolutions Concerning the Execution of Juveniles and Persons with Mental Retardation, 61 Law & Contemp. Probs. 89 (1998). Finally, public opinion polls have repeatedly shown that, even among death penalty advocates, there is scant support for executing the mentally retarded.17

*804When this evidence is viewed in conjunction with the legislative enactments and jury studies discussed above, the conclusion is compelling: executing the mentally retarded is considered cruel and unusual punishment by numerous facets of contemporary society. Thus, there exists today evidence of a substantial societal change in attitude since 1989 and, in our opinion, that evidence warrants a different conclusion. See Ford v. Wainwright, 477 U.S. at 408,106 S.Ct. at 2601.18

Tennessee

Having surveyed the national landscape, we now likewise find substantial evidence of the evolving societal view in our own state. The Tennessee legislature, which “speaks for the people on matters of public policy of the state,”19 joined those states trumpeting for an end to the execution of the mentally retarded. We find it particularly significant that our General Assembly was the first in the country to respond to the Penry decision by enacting legislation to prohibit the execution of mentally retarded individuals convicted of a first degree murder. See Tenn.Code Ann. § 39-13-203 (1991). The legislation was passed in the Tennessee House of Representatives by a vote of 81 to 3 and in the Tennessee Senate by a vote of 28 to 3. See Protecting the Mentally Retarded From Capital Punishment, 22 N.Y.U. Rev. L. & Soc. Change at 116. The very timing of the statute’s passage, less than a year after the Penry Court held that execution of the mentally retarded did not violate national standards of decency, suggests that the legislature intended to reject Penry. The legislative history of the statute reinforces this conclusion. In Senate debates on the bill, for example, Senator Greer stated:

Some people are framing the issue on this bill as whether you’re for or against the death penalty. And that’s not really the issue.... I favor the death penalty, but I’m going to vote for ... [the] bill for this reason: in my view, it’s just not proper in a civilized society for the State to be in the business of executing children or those who are mentally retarded, and I think we ought to pass this bill and that ought to become the policy of the State.

Tenn. S., Debate-on H.B. 2107 on the Floor of the Senate, 96th Gen. Assembly, 2nd Reg. Sess. (Apr. 12, 1990) (Tape S-106B) (Substituted for S.B. 1851). Numerous other legislators echoed Senator Greer’s concerns. See, e.g., id. (statement of Sen. Darnell) (“I think this, in a civilized society, is a minimum to say that we’re not going to put ... [mentally retarded individuals] to death.”); (statement of Sen. Haynes) (“From a conservative standpoint, I think it’s a protection to society.... I happen to agree with the death penalty. I just don’t believe mentally retarded people ought to be electrocuted.”). Such statements are convincing evidence that the legislature, in passing this statute, con*805sciously intended to recognize that the people of Tennessee no longer approved of executing the mentally retarded.

In considering the statute as a reflection of the emerging societal view in our state, we reject the dissent’s argument that we have elevated the legislative enactment of the statutory prohibition into a constitutional rule in violation of Tenn. Const, article I, § 1 or article XI, § 3, or that we have interfered with the authority of the legislature to set and define applicable punishments in violation of Tenn. Const, article II, § 2. First, the United States Supreme Court in Penry stressed that “the clearest and most reliable objective evidence of contemporary values is the legislation enacted by the country’s legislatures.” 492 U.S. at 331, 109 S.Ct. at 2953. Given this language in Penry, a case the dissent has described as “well-reasoned,” it is hardly arguable that the societal view in Tennessee is against the execution of the mentally retarded; indeed the statute was passed by nearly unanimous votes in both the State House of Representatives and the State Senate.20 Second, the dissent neglects to note that our consideration of the statute and the emerging societal view is but one prong of the three-prong analysis applicable under article I, § 16.

The Supreme Court of Georgia, faced with an issue similar to the one under consideration in this case, has also relied on their statute to hold that contemporary standards of decency no longer supported execution of the mentally retarded. See Fleming v. Zant, 259 Ga. 687, 386 S.E.2d 339 (1989). The Court stated:

The legislative enactment reflects a decision by the people of Georgia that the execution of mentally retarded offenders makes no measurable contribution to acceptable goals of punishment. Thus, although there may be no “national consensus” against executing the mentally retarded, this state’s consensus is clear.

The “standard of decency” that is relevant to the interpretation of the prohibition against cruel and unusual punishment found in the Georgia Constitution is the standard of the people of Georgia, not the national standard. Federal constitutional standards represent the minimum, not the maximum, protection that this state must afford its citizens. Thus, although the rest of the nation might not agree, under the Georgia Constitution, the execution of the mentally retarded constitutes cruel and unusual punishment.

Id. at 342 (footnote and citations omitted).

Accordingly, in conducting the appropriate analysis under article I, § 16 of the Tennessee Constitution, it is unmistakably clear that the societal consensus in Tennessee, as reflected in the overwhelming vote and comments of the legislature, directly repudiates the Penry decision’s constitutional sanction on executing the mentally retarded. We therefore conclude that the execution of mentally retarded individuals violates evolving standards of decency that mark the progress of a maturing society both nationally and in the State of Tennessee.

Proportionality

The second prong of the analysis under the Eighth Amendment to the United States Constitution and article I, § 16 of the Tennessee Constitution is whether the punishment is grossly disproportionate. The proportionality analysis must focus upon myriad factors regarding the de*806fendant and the offense. As the United States Supreme Court has expressed, a court must “gauge whether a punishment is disproportionate by comparing the ‘gravity of the offense,’ understood to include not only the injury caused, but also the defendant’s moral culpability, with the ‘harshness of the penalty.’ ” Penny v. Ly-naugh, 492 U.S. at 342, 109 S.Ct. at 2959-60 (Brennan, J., concurring and dissenting) (quoting in part Solem v. Helm, 463 U.S. 277, 292, 103 S.Ct. 3001, 3010, 77 L.Ed.2d 637 (1983) (emphasis added)); see also En-mund v. Florida, 458 U.S. 782, 825, 102 S.Ct. 3368, 3391, 73 L.Ed.2d 1140 (1982) (O’Connor, J., dissenting) (noting that the Eighth Amendment concept of “proportionality requires a nexus between the punishment imposed and the defendant’s blameworthiness”).

As we have emphasized, all mentally retarded individuals, regardless of their level or class of retardation, have significantly subaverage general intellectual functioning and significant limitations in adaptive functioning. The deficiencies include impaired communication and comprehension skills, poor self-concept and self-perception, impaired attention and memory capacities, and a lack of knowledge about basic facts. See Capital Punishment for Mentally Retarded Offenders, 19 Sw. U.L.Rev. at 107-08. More importantly, these and other impairments necessarily permeate every aspect of a mentally retarded individual’s encounter with the criminal justice system. As one commentator has said,

[MJental retardation may have a significant impact on an individual who finds himself involved with the criminal justice system, particularly in the context of confessions and interrogations. It is well-recognized that mental retardation is not a per se bar to voluntary interrogations and confessions, although it may be a fact to be weighed in evaluating the voluntariness of a confession. Many mentally retarded people may be less likely to withstand police coercion or pressure due to their limited communication skills, their predisposition to answer questions so as to please the questioner rather than to answer the question accurately, and their tendency to be submissive.

Putting the Mentally Retarded Criminal Defendant to Death, 52 Ala. L.Rev. at 917 (emphasis added); see also Mary D. Bick-nell, Constitutional Law: The Eighth Amendment Does Not Prohibit the Execution of Mentally Retarded Convicts, 43 Okla. L.Rev. 357, 362 (1990) (“[T]he mentally retarded individual is particularly vulnerable to any police coercion used in obtaining confession.”).

The dissent’s view ignores the impairments in intelligence and adaptive functioning and inquires only into whether a mentally retarded person understands the nature of his or her actions, knows right from wrong, or can conform his or her conduct to the requirements of the law. We reemphasize that the dissent’s narrow view would effectively protect only those mentally retarded persons who can also establish legal insanity. Again, this constricted view misses the basic issue in this case. For example:

[MJental retardation, in and of itself, does not render an individual incompetent to stand trial or incompetent to enter a guilty plea. However, certain characteristics that are common among people with mental retardation, such as the tendency to be easily led, a poor understanding of the consequences of one’s actions, the desire to hide one’s mental retardation, and the desire to please authority figures, can affect the quality and ability of a mentally retarded person to make decisions that are in *807his best interest. Thus, the ability of the mentally retarded defendant to assist counsel in preparing a case and in making critical decisions about the course of a capital murder trial may be compromised.

Putting the Mentally Retarded Criminal Defendant to Death, 52 Ala. L.Rev. at 918 (emphasis added).

In short, there are fundamental concerns that necessarily bear on a mentally retarded person’s mental state, culpability, blameworthiness, and the proportionality of death as a punishment. As summarized persuasively by one author:

The most significant of all of the characteristics of the mentally retarded is that they may have impaired impulse control as well as an incomplete or immature concept of blameworthiness and causation. The first defect can result in impulsive behavior, the consequence of which the [mentally retarded individual] may have difficulty or even be utterly unable to appreciate. The second defect, the failure to appreciate the concept of blameworthiness, is the most important of all because it can render a mentally retarded offender unable to understand that certain repercussions flow from certain of his acts. This can have an enormous impact on ... blameworthiness ....

Capital Punishment for Mentally Retarded Offenders, 19 Sw. U. L.Rev. at 108 (emphasis added); see also Putting the Mentally Retarded Criminal Defendant to Death, 52 Ala. L.Rev. at 918.

Finally, despite the observations of the dissent, the issue in this case is not whether the mentally retarded may possess the culpability and blameworthiness te be convicted and punished of a crime. They certainly may. The issue is also not whether the mentally retarded may plead guilty, stand trial, serve as a witness, or any of the other “facts” listed by the dissent. The issue, rather, is whether the punishment of a mentally retarded offender, who by definition suffers significantly impaired intelligence and adaptive behavior, may extend beyond life imprisonment without parole and include the extreme and maximum penalty of death under article I, § 16 of the Tennessee Constitution. As it has long been recognized, the penalty of death is “ ‘qualitatively different’ ” from any other sentence and this “ ‘qualitative difference between death and other penalties calls for a greater degree of reliance when the death sentence is imposed.’ ” State v. Terry, 813 S.W.2d 420, 425 (Tenn.1991) (quoting Woodson v. North Carolina, 428 U.S. 280, 305, 96 S.Ct. 2978, 2991 (1976), and Lockett v. Ohio, 438 U.S. 586, 604, 98 S.Ct. 2954, 2964, 57 L.Ed.2d 973 (1978)).

For all of the foregoing reasons, we find persuasive the view of Justice Brennan who, writing for the four-justice dissent in Penry, observed that the “impairment of a mentally retarded offender’s reasoning abilities, control over impulsive behavior, and moral development ... limits his or her culpability so that, whatever other punishment might be appropriate, the ultimate penalty of death is always and necessarily disproportionate to his or her blameworthiness and hence is unconstitutional.” Penry v. Lynaugh, 492 U.S. at 346, 109 S.Ct. at 2961 (Brennan J., concurring and dissenting).21 Accordingly, we hold that the execution of mentally retarded individuals is grossly disproportionate under the Eighth Amendment to the United States *808Constitution and article I, § 16 of the Tennessee Constitution.

Penological Objectives

The third and final prong of the analysis is whether the execution of mentally retarded persons achieves legitimate peno-logical objectives. The dissent asserts that this prong is satisfied because the execution of mentally retarded persons achieves the objectives of deterrence and retribution. Deterrence, obviously, is the theory that a punishment will prevent others from committing similar offenses. Ford v. Wainwright, 477 U.S. at 421, 106 S.Ct. at 2607. Retribution is the theory that a defendant be punished appropriately for the crime committed; it depends on the defendant’s awareness of both the punishment and its purpose. See id.

All of the concerns that we have discussed with regard to proportionality apply with equal force to this portion of the analysis. As the Georgia Supreme Court observed, the legislative enactment that prohibited the execution of mentally retarded individuals “reflects a decision by the people ... that [such executions] make no measurable contribution to acceptable goals of punishment.” Fleming v. Zant, 386 S.E.2d at 342. The dissent in Penry reached the same conclusions:

Since mentally retarded offenders as a class lack the culpability that is a prerequisite to the proportionate imposition of the death penalty, it follows that execution can never be the “just desserts” of a retarded offender ..., and that the punishment does not serve the retributive goal....

Furthermore, killing mentally retarded offenders does not measurably contribute to the goal of deterrence. It is highly unlikely that the exclusion of the mentally retarded from the class of those eligible to be sentenced to death will lessen any deterrent effect the death penalty may have for nonretarded potential offenders, for they, of course, will ... remain at risk of execution. And the very factors that make it disproportionate and unjust to execute the mentally retarded also make the death penalty of the most minimal deterrent effect so far as retarded potential offenders are concerned.

Penry v. Lynaugh, 492 U.S. at 348, 109 S.Ct. at 2962 (Brennan J., concurring and dissenting) (citations omitted).

These persuasive arguments with respect to deterrence and retribution have been echoed by several commentators:

[T]he death penalty will not deter other mentally retarded individuals from committing crimes because they are not able to weigh the cost of the criminal act, the consequences of the punishment, or the benefits of alternatives. Therefore, inflicting the death penalty on a mentally defective person becomes a process in which society seeks vengeance, not retribution or deterrence. Such a result is neither civilized, nor humane.

Constitutional Law, 43 Okla. L.Rev. at 368; see also Capital Punishment for Mentally Retarded Offenders, 19 Sw. U.L.Rev. at 139 (arguing that “incapacitation, deterrence and retribution, the three penological justifications offered in support of capital punishment, do not provide a sound superstructure for this final form of punishment, especially in cases involving the mentally retarded.... ”).

The dissent argues that execution of the mentally retarded achieves valid penological objectives unless the mentally retarded defendant also establishes the cognitive, moral, or volitional incapacity to distinguish right from wrong, understand the nature of his or her actions, or conforms his or her conduct to the requirements of the law. Moreover, to emphasize its point, *809the dissent engages in the fact-finding exercise of reviewing this case and concludes that the petitioner did not lack such cognitive, moral, or volitional incapacities, even though the issue has not been raised, litigated, briefed or argued by the parties.

The dissent argues that its factual findings stem from the jury’s verdict. The fallacy in the dissent’s claim is that no jury has ever considered the defendant’s volitional, moral, and cognitive capacities, the defendant’s ability to understand right from wrong, the defendant’s ability to understand the nature of his actions, or the defendant’s ability to conform his conduct to the requirements of the law. Instead, the dissent has established its own standard of what marginal constitutional protection is due the potentially mentally retarded offender and then has made determinations regarding the petitioner’s cognitive, moral, and volitional abilities to satisfy that standard.22

In any event, we do not hold that the conviction and punishment of a mentally retarded defendant never achieves valid penological goals. Rather, our conclusion is that any penological objectives attained through the execution of a mentally retarded defendant are minimal at best and insufficient for the purpose of our analysis under article I, § 16. The dissent somehow finds an inherent contradiction in the conclusion that penological objectives may be served by imposing a lesser punishment than death but not for the extreme and final punishment of death. We can only comment that no statement better illustrates the dissent’s view of this case and its misapprehension of the relevant analysis. The very nature of the analysis under the Eighth Amendment or article I, § 16 asks whether a particular punishment is cruel and unusual. Moreover, as we have commonly recognized, a sentence of death is final, irrevocable, and “qualitatively different” than any other form or level of punishment.

Accordingly, having considered the foregoing arguments and the concerns we have previously discussed, we hold that the execution of mentally retarded individuals fails to achieve legitimate penological objectives for punishment as required by the Eighth Amendment to the United States Constitution and article I, § 16 of the Tennessee Constitution.

Other Considerations

In reaching our conclusion, we wish to separately address the arguments that executing the mentally retarded is not cruel and unusual punishment because mental retardation may be considered by the jury as mitigating evidence and because some mentally retarded individuals may rely upon the defense of insanity. There is little in either alternative that offers reasonable safeguards to the mentally retarded or addresses the concerns outlined in this opinion.

For instance, the jury’s consideration of mental retardation as a mitigating factor is by itself insufficient to address the concerns protected under the Eighth Amendment or article I, § 16. In such circumstances, evidence of mental retardation would only be weighed in conjunction with one or more aggravating circumstances, such as the heinousness of the crime or a defendant’s prior record. In our opinion, the weighing process would not sufficiently isolate the consideration given to the issue of mental retardation and would not provide reasonable assur-*810anee that an individualized decision will be made as to whether the death penalty was appropriate punishment for a particular mentally retarded offender. See Penry v. Lynaugh, 492 U.S. at 347, 109 S.Ct. at 2962 (Brennan J., concurring and dissenting) (“Lack of culpability as a result of mental retardation is simply not isolated at the sentencing stage as a factor that deter-minatively bars a death sentence.... ”). In sum, the limitations and impairments associated with mental retardation warrant more consideration than simply allowing the evidence to be weighed in the mix of aggravating and mitigating circumstances. Indeed, the Tennessee legislature obviously shared this view in the passage of Tenn. Code Ann. § 39-13-203, which prohibits imposition of a death sentence upon persons found to be mentally retarded; otherwise, it simply could have listed evidence of mental retardation as among the mitigating factors in Tenn. Code Ann. § 39 — 13— 204(j), the first degree murder death penalty statute.

Likewise, the State’s assertion that some mentally retarded persons may rely upon the defense of insanity offers little protection with regard to capital sentencing. The defense of insanity is a complete defense to criminal charges only where a defendant meets the substantial burden of proving that he or she was unable to appreciate the nature or wrongfulness of his or her acts due to a severe mental illness or defect. See Tenn. Code Ann. § 39-11-501 (1997). The relevant issue in this case, however, is not whether a mentally retarded individual may be held responsible for a criminal offense, but whether that individual may be executed as a punishment for the offense. The State, as well as the dissent, would nonetheless conclude that only a mentally retarded person who establishes a complete defense to the charged offense may be exempt from the death penalty.

Moreover, placing such a burden on the mentally retarded fails to distinguish mental retardation from mental illness. Although a mentally retarded person may also have a mental illness, the two issues are not one and the same. See Putting the Mentally Retarded Criminal Defendant to Death, 52 Ala. L.Rev. at 915. Mental retardation, by definition, is accompanied by serious limitations on intelligence and adaptive behavior; mental illness is not. Mental retardation, by definition, must also manifest by age 18; mental illness may or may not. Id. Finally, mental retardation does not equate to legal insanity, nor does it necessarily make the defense of legal insanity any easier to establish. It also bears noting that the complete defense of insanity is asserted in perhaps as few as one percent of all felony cases and is successful in even fewer. See Jodie English, The Light Between Twilight and Dusk: Federal Criminal Law and the Volitional Insanity Defense, 40 Hastings L.J. 1, 9 (1988) (“Contrary to public opinion, ... the insanity defense is infrequently raised and even less frequently successful.”). Accordingly, what the State posits as a safeguard for mentally retarded individuals is in reality no safeguard at all.

Application of Holding Retroactivity

We next must determine whether our conclusion that the execution of mentally retarded persons violates the Eighth Amendment to the United States Constitution and article I, § 16 of the Tennessee Constitution constitutes a new rule warranting retroactive application,

A case “announces a new rule when it breaks new ground or imposes a new obligation on the States or the Federal government.” Teague v. Lane, 489 U.S. 288, 301, 109 S.Ct. 1060, 1070, 103 L.Ed.2d *811334 (1989) (citations omitted). In other words, “a case announces a new rule if the result was not dictated by precedent existing at the time the defendant’s conviction became final.” Id.; see also Meadows v. State, 849 S.W.2d 748, 751 (Tenn.1993).

The United States Supreme Court has said that a new rule of federal constitutional law is to be applied in cases on collateral review only if it (1) places certain kinds of primary, private individual conduct beyond the power of the state to proscribe or (2) requires the observance of procedures implicit in the concept of ordered liberty. Teague v. Lane, 489 U.S. at 307, 109 S.Ct. at 1073. We have adopted a somewhat different standard in Tennessee: “a new state constitutional rule is to be retroactively applied to a claim for post-conviction relief if the new rule materially enhances the integrity and reliability of the fact finding process of the trial.” Meadows v. State, 849 S.W.2d at 755; see also Tenn. Code Ann. § 40-30-222 (1997) (citing the Teague standard for retroactivity).

In deciding Penny, the United States Supreme Court recognized that a holding that the Eighth Amendment prohibited the execution of mentally retarded persons would be a new rule because it would “ ‘brea[k] new ground’ and would impose a new obligation on the States and the Federal Government.” Penny v. Lynaugh, 492 U.S. at 329, 109 S.Ct. at 2952 (alteration in original) (citations omitted). The Court also said that such a rule would apply retroactively on collateral review:

[T]he first exception set forth in Teague should be understood to cover not only rules forbidding criminal punishment of certain primary conduct but also rules prohibiting a certain category of punishment for a class of defendants because of their status or offense. Thus, if we held ... that the Eighth Amendment prohibits the execution of mentally retarded persons ... regardless of the procedures followed, such a rule would fall under the first exception to the general rule of nonretroactivity and would be applicable to defendants on collateral review.

Id. at 330,109 S.Ct. at 2953.

We conclude that our holding under article I, § 16 of the Tennessee Constitution likewise constitutes a new rule. This is an issue of first impression by this Court, and the result is in no way dictated by our existing precedent. See State v. Laney, 654 S.W.2d 383, 389 (Tenn.1983) (stating that a defendant’s “low intelligence” was a mitigating factor but did not render the death penalty cruel and unusual punishment). Moreover, we agree with the observation in Pem'y that such a rule warrants retroactive application to cases on collateral review. In sum, our holding that article I, § 16 of the Tennessee Constitution prohibits execution of those defendants who are mentally retarded materially enhances the integrity and the reliability of the fact finding process of the trial. See Meadows v. State, 849 S.W.2d at 755; Tenn.Code Ann. § 40-30-222 (1997).

Standards on Remand

Our holding dictates that this case be remanded to the trial court for further proceedings on the question of whether the petitioner, Heck Van Tran, is mentally retarded. Although the petitioner’s motion to reopen alleged that he had new scientific evidence that he was actually innocent under Tenn.Code Ann. § 40-30-217(a)(2), it is our view that the motion is more appropriately based on the provisions of TenmCode Ann. § 40-30-217(a)(l), which provides that the “claim in the motion is based upon a final ruling of an appellate court establishing a constitutional right *812that was not recognized as existing at the trial, if retrospective application of that right is required.” As such, we need not address the requirements of Tenn.Code Ann. § 40-30-217(a)(2).

We recognize that the petitioner’s motion to reopen did not, and could not at the time it was filed, assert a “final appellate ruling” with regard to the unconstitutionality of executing the mentally retarded. Having now determined that the unique circumstance of this case raises a constitutional issue that warrants review and that our holding — a new rule of constitutional law — warrants retroactive application, we believe fundamental fairness dictates that the petitioner have a meaningful opportunity to raise this issue.

The application of fundamental fairness in the context of post-conviction procedures is hardly new. In Williams v. State, 44 S.W.3d 464 (Tenn.2001), for example, a majority of this Court agreed that attorney misrepresentation may toll the post-conviction statute of limitations despite the presence of statutory language stating that the statute of limitations shall not be tolled for any reason. See also Seals v. State, 23 S.W.3d 272 (Tenn.2000) (mental incompetency may toll statute of limitations despite anti-tolling language).

Accordingly, under the unusual facts of this case, in which the petitioner has raised an issue with obvious constitutional implications that a majority of the Court has chosen to address and not ignore, we believe fundamental fairness dictates that he have an opportunity to litigate his claim under the new constitutional rule of law we have announced. Moreover, allowing the petitioner to proceed serves the interest of judicial economy given that he could simply file a new motion to reopen relying on this decision under Tenn.Code Ann. § 40-30-217(a)(l). Finally, if the dissent’s procedural arguments were adopted as the majority holding of this Court, the only remaining alternative in this case would be that one potentially mentally retarded person may be executed before the issue is reviewed.

On remand, the trial court shall hear the petitioner’s motion to reopen and make a determination as to the petitioner’s alleged mental retardation. The applicable criteria are those presently set forth by statute: (1) significantly subaverage general intellectual functioning as evidenced by a functional intelligence quotient (I.Q.) of seventy (70) or below; (2) deficits in adaptive behavior; and (3) mental retardation manifested during the developmental period, or by eighteen (18) years of age. See TenmCode Ann. § 39-13-203 (1997); see also Fleming v. Zant, 386 S.E.2d at 342 (adopting and applying the statutory definition of mental retardation as the constitutional standard).

Conclusion

We conclude that there is compelling evidence that the execution of mentally retarded individuals violates the evolving standards of decency that mark the progress of a maturing society both nationally and in the State of Tennessee. We also have determined that the execution of any mentally retarded individual, who by definition, has significantly subaverage intelligence functioning and deficits in adaptive behavior, is grossly disproportionate, and serves no valid penological purpose. We therefore conclude that the execution of a mentally retarded individual violates the Eighth Amendment to the United States Constitution and article I, § 16 of the Tennessee Constitution. The judgment of the Court of Criminal Appeals is reversed, and this case is remanded to the trial court for further proceedings. It appearing that the petitioner is indigent, *813costs of this appeal are taxed to the State of Tennessee.

WILLIAM M. BARKER, J., filed a concurring and dissenting opinion, in which JANICE M. HOLDER, J., joined.

WILLIAM M. BARKER, J.,

with whom JANICE M. HOLDER, J., joins, concurring in part, dissenting in part.

With its decision today, a majority of this Court has effectively permitted a defendant, who was sentenced to death in 1989 for the brutal execution of a 74-year-old grandmother, an opportunity to escape the ultimate punishment for his actions solely because he has managed to obtain a lower score on a revised I.Q. test than he was previously able to do. Before today, the Constitution of this State has never been held to provide blanket capital immunity to a class of persons based only on the fact of low intellectual ability and deficits in adaptive behavior. Instead, the Constitution has barred such executions only when the defendant’s mental condition displaces the following capacities: (1) the cognitive capacity to appreciate that certain action will lead to the death of others; (2) the moral capacity to appreciate the wrongfulness of murder; or (3) the volitional capacity to behave in a lawful manner.

By permitting Heck Van Tran the opportunity to escape his capital sentence because of his new score on an I.Q. test, the majority ignores that Heck Van Tran has not argued that his alleged condition ever affected his abilities to appreciate that certain actions would lead to the death of others. The majority ignores that Heck Van Tran has not argued that his alleged condition ever affected his ability to appreciate the wrongfulness of murder. The majority also ignores that Heck Van Tran has not argued that his alleged condition ever affected his ability to behave in a lawful manner. Instead, the majority holds that Heck Van Tran should escape his capital sentence because his new score on an updated I.Q. test removes his moral blameworthiness for the senseless and intentional execution of an elderly victim, Kai Yin Chuey. I simply cannot agree.

Moreover, the majority has completely disregarded the petitioner’s claims alleging “new scientific evidence establishing that [he] is actually innocent of the offense or offenses for which [he] was convicted” under Tennessee Code Annotated section 40-30-217(a)(2). Instead, the majority has determined that the motion to reopen is “more appropriately” based on the provisions of Tennessee Code Annotated section 40-30-217(a)(l), which provides in pertinent part that the “claim in the motion is based upon a final ruling of an appellate court establishing a constitutional right that was not recognized as existing at the time of trial.” Although the majority has extended this very narrow basis to reopen to apply in this case, the constitutional issue now raised for the first time in this motion to reopen has clearly been waived by the petitioner’s failure to raise it in his original post-conviction petition. See TenmCode Ann. § 40-30-206(g). In accordance with our holding in State v. West, 19 S.W.3d 753 (Tenn.2000), this Court lacks the authority to consider this constitutional issue, and it should therefore be dismissed. Accordingly, because subsection (a)(1) is not an applicable avenue for relief in this case, the petitioner must seek relief on other grounds.

Indeed, the petitioner filed his motion to reopen pursuant to subsection (a)(2), alleging that an updated version of the I.Q. test has established his mental retardation thereby rendering him “actually innocent” of capital punishment. This Court has not previously considered the proper stan*814dards governing the admissibility of “new scientific evidence” under Tennessee Code Annotated section 40-30-217(a)(2). Consequently, it is inappropriate for the petitioner to assume that the WAIS-III qualifies as such without further inquiry. I also disagree that the language “actual innocence of the offenses for which he was convicted” in this subsection includes innocence of, or ineligibility for, the death penalty. Accordingly, I am unable to join the majority’s decision permitting the petitioner to reopen his post-conviction petition under either subsection (a)(1) or, per the petitioner’s request, subsection (a)(2), and for the reasons given below, I respectfully dissent.

A review of the factual history of this case will provide a better understanding of the procedural and substantive issues before the Court:

FACTUAL BACKGROUND

In 1987, during the course of robbing a family-owned restaurant, the petitioner and three other defendants shot and killed three innocent victims, all family members. A fourth family member was brutally beaten but eventually recovered. The evidence at the petitioner’s trial revealed that he shot two of the victims, including seventy-four year-old Kai Yin Chuey, multiple times including once in the throat and once in the back of the head. State v. Van Tran, 864 S.W.2d 465, 469 (Tenn.1993). The petitioner then entered the restaurant office where he knew valuables were kept, and he stole gold and jewelry having an estimated wholesale value of $25,000.

Following the robbery, three of the criminals took most of the stolen jewelry and fled to Houston, Texas. There, the defendant managed to sell some of the stolen gold for $4,000, which the trio divided amongst themselves. For almost six months after the robbery, the petitioner remained in hiding until he was arrested in Houston. At the time of his arrest, the petitioner initially gave the police a fictitious name upon inquiry. After he was advised of his Miranda rights, he was asked if he knew why he was being arrested, to which he replied, “For a shooting in Memphis.” Later, the petitioner gave a written statement in which he admitted his involvement in the crimes.

The jury found him guilty of three counts of first degree murder and one count of robbery by use of a deadly weapon and sentenced him to death for each of the murder convictions. The court also sentenced the petitioner to thirty years imprisonment for the robbery to be served concurrently with the death sentences. On appeal, his convictions and one death sentence were affirmed by this Court.

On March 7, 1995, the petitioner filed a petition for post-conviction relief alleging, among other things, that he was mentally retarded and thus ineligible for the death penalty under Tennessee Code Annotated section 39-13-203. The trial court conducted an evidentiary hearing in October 1997. At the hearing, the petitioner presented the testimony of Dr. Andrew J. Adler, the psychologist who tested the petitioner using the Vineland Adaptive Behavior Scale and the Wechsler Adult Intelligence Scale Revised (WAIS-R). Dr. Adler testified that the petitioner had deficits in adaptive behavior that had manifested during the petitioner’s developmental period and that the petitioner had a full — scale I.Q. of sixty-seven. He concluded that Van Tran was therefore mentally retarded as defined by section 39-13-203(a).1 However, the State’s expert, psy*815chologist Dr. Lynn Zager, testified that Dr. Adler’s calculations of the WAIS-R test scores were erroneous and that the petitioner’s I.Q. was actually seventy-two. Following the hearing, the post-conviction court found Dr. Adler’s calculation to be in error and dismissed the petition. The Court of Criminal Appeals affirmed the trial court’s dismissal and further held that a proceeding for post-conviction relief is inappropriate for addressing the issue of present incompetency to be executed. On November 23, 1999, this Court affirmed the dismissal of the post-conviction petition. Van Tran v. State, 6 S.W.3d 257, 261 (Tenn.1999).

Within a month after this Court’s decision to affirm the dismissal of the post-conviction petition, Dr. Adler again tested the petitioner using the Wechsler Adult Intelligence Scale III, an updated version of the WAIS-R. Dr. Adler determined that the results of this test showed that the petitioner’s full-scale I.Q. was sixty-five. Relying on this information, the petitioner then filed a motion to reopen his previous post-conviction petition pursuant to Tennessee Code Annotated section 40-30-217(a)(2).2

The trial court denied the motion to reopen, finding that the evidence presented by the petitioner, even if considered “new scientific evidence,” did not establish his actual innocence of the murders for which he was convicted. The Court of Criminal Appeals affirmed the trial court’s denial of the motion to reopen and we *816granted permission to appeal. In this Court, the petitioner presents three issues for our review: First, he argues that the Wechsler Adult Intelligence Scale III test should be considered “new scientific evidence” pursuant to section 40-30-217(a)(2). Second, he argues that the clear statutory-language “actually innocent of the offense” in section 40-30-217(a)(2) should be construed to mean “actual innocence of or ineligibility for the death penalty.” And third, he asserts that the Tennessee statute prohibiting the execution of mentally retarded capital offenders, Tenn.Code Ann. § 39-13-203, should be applied retroactively, thereby entitling him to a reduced sentence.

After hearing oral argument in April 2001, this Court requested that the parties file supplemental briefs addressing the additional issue of whether executing a mentally retarded defendant would violate either the Eighth Amendment of the United States Constitution or Article I, section 16 of the Tennessee Constitution. The majority today holds first, that section 39 — 13— 203 has prospective application only and therefore does not serve to relieve the petitioner from his sentence. The majority is entirely correct in this decision, and I concur in that part of the opinion. However, for the reasons set forth below, I disagree with the majority’s conclusions regarding both procedural and substantive matters in this case.

I. PROCEDURAL ANALYSIS UNDER THE POST CONVICTION PROCEDURE ACT

Although largely overlooked by the majority, this case presents several significant procedural issues concerning the ability to reopen a post-conviction petition under Tennessee Code Annotated section 40-30-217(a). Despite the fact that the petitioner filed his claim solely pursuant to subsection (a)(2), the majority does not address this issue on its merits. Invoking the doctrine of fundamental fairness, the majority instead concludes that the petitioner may reopen his petition under subsection (a)(1). Because the petitioner is not constitutionally entitled to reopen his post-conviction petition, but may do so only when the statute permits its reopening, I would deny his petition for failing to satisfy any of the statutory requirements for reopening his post-conviction petition.

A. TENNESSEE CODE ANNOTATED SECTION I0-S0-217(a)(l)

Today, the majority has decided that the petitioner may file a new motion to reopen pursuant to subsection (a)(1). In so deciding, the majority has fashioned a unique procedure to provide the petitioner this avenue for relief. First, the Court has improperly addressed a constitutional issue that has been waived because the petitioner failed to raise it in his original post-conviction petition. Nevertheless, by ordering the parties to supply supplemental briefing on this constitutional issue, the Court has excused the waiver, addressed the substantive issue, and created a “final appellate ruling establishing a constitutional right.” The petitioner is now being allowed to refile his motion to reopen pursuant to subsection (a)(1), basing his claim on the majority’s decision today.

However, the majority overlooks a fundamental procedural flaw in its analysis: according to our unanimous holding in State v. West, 19 S.W.3d 753 (Tenn.2000), once an issue has been waived by a petitioner, the Court lacks the authority to excuse that waiver, see also Tenn.Code Ann. § 40-30-206(g); Tenn. Sup.Ct. R. 28, § 3(B). The unanimous order previously entered cannot be held to have placed the constitutional issue properly before this *817Court. For the reasons that follow, the constitutional issue should be dismissed, and the petitioner must seek to reopen his post-conviction petition on other grounds.

In 1995, Van Tran filed his petition for post-conviction relief. He raised numerous and various claims, including an allegation that he was mentally retarded and therefore statutorily ineligible for the death penalty under section 39-13-203. The trial court conducted an evidentiary hearing in 1997, and the petitioner was provided with a full, fair, and meaningful “opportunity to present proof and argument on the petition for post-conviction relief.” Cf. House v. State, 911 S.W.2d 705, 714 (Tenn.1995); Tenn.Code Ann. § 40-30-206(h). Based on all the evidence presented, the trial court found the petitioner’s claims of mental retardation to be without merit and subsequently dismissed his petition.

Despite having a full, fair, and meaningful opportunity to be heard in 1997, the petitioner never raised the issue of whether execution of mentally retarded persons violates Article I, section 16 of the Tennessee Constitution.' In fact, he did not even assert this issue in the current proceeding to reopen until he applied for permission to appeal to this Court. Where a petitioner fails to raise an issue, despite having had the opportunity to do so, that issue is deemed waived under the Post Conviction Procedure Act. See Tenn. Code Ann. § 40-30-206(g) (1997).

Because the petitioner has previously waived the substantive constitutional issue before us now, the Post-Conviction Procedure Act does not permit him, outside of the exceptions listed in the statute, to assert that issue in any subsequent proceeding. The majority today appears to overlook the fact that petitioner’s previous waiver of the substantive constitutional issue renders this Court without statutory authority to grant relief to the petitioner based on this issue under the post-conviction statutes. Consequently, because the substantive constitutional issue is not properly before the Court, the majority has inappropriately used subsection (a)(1) to give the petitioner an opportunity to avoid his capital sentence.

Importantly, I do not find that our previous order requesting additional briefing on this issue has effectively excused the petitioner’s previous waiver. Once an issue has been waived by a defendant in the post-conviction context, this Court possesses no authority, whether by statute, rule, or the plain error doctrine, to excuse that waiver in order to reach the merits of a claim. See West, 19 S.WM at 756-57.3 Consequently, to the extent that our previous order requesting additional briefing could be construed as excusing the petitioner’s waiver of that issue, the order was beyond the scope of our authority under the Post Conviction Procedure Act. Under no set of circumstances can our previous order be construed to place the substantive constitutional issue properly before the Court for resolution on its merits.

Therefore, in accordance with the Post-Conviction Procedure Act and our previous holding in West, I find that the constitutional issue presently addressed by the Court has been previously waived by the *818petitioner and is beyond the authority of this Court to review. Because we also lack the authority to excuse the petitioner’s waiver, we are likewise without authority to address the petitioner’s constitutional claim on its merits as the majority has done today. Accordingly, I would hold that the substantive constitutional issue should be dismissed, thereby prohibiting the petitioner from filing a future motion to reopen under subsection (a)(1).

B. TENNESSEE CODE ANNOTATED SECTION ⅛0-80-217(a) (2)

Without any explanation, the majority asserts that a motion to reopen may be based on a claim involving either a “new legal issue” or new scientific evidence establishing that the petitioner is actually innocent of the offense for which he or she was convicted.4 Presumably, the majority has used the language “new legal issue” as a paraphrase for the precise statutory language of section 40-30-217(a)(l), which allows a petitioner to base a claim in a motion to reopen based upon a “final ruling of an appellate court establishing a constitutional right that was not recognized as existing at the time of trial.”

Alternatively, as the majority has recognized, the petitioner may file a motion to reopen based on a claim of new scientific evidence establishing actual innocence of the offense or offenses for which the petitioner was convicted, Tenn.Code Ann. § 40-30-217(a)(2). Instead, the petitioner in this case has filed his motion to reopen presumably pursuant to subsection (a)(2), alleging that the WAIS-III provides new scientific evidence establishing his mental retardation, thereby rendering him actually innocent of his capital sentence. The majority never discusses the propriety of the petitioner’s claim, specifically whether the petitioner has indeed satisfied the strict requirements for reopening a post-conviction petition under section 40-30-217(a)(2). Because this Court has never before considered the proper standard governing the admissibility of “new scientific evidence,” further inquiry is necessary to determine whether the petitioner has at all satisfied the strict requirements for reopening a post-conviction petition under section 40-30-217(a)(2). More importantly, I cannot accept the petitioner’s expanded definition of the phrase “actual innocence of the offenses for which he was convicted” to include innocence of or ineligibility for the death penalty. This interpretation not only neglects the plain, unambiguous language of the statute, but, if relying on the United States Supreme Court’s decision in Sawyer v. Whitley, 505 U.S. 333, 112 S.Ct. 2514, 120 L.Ed.2d 269 (1992), also ignores that the General Assembly has adopted a more narrow definition of the “actual innocence” exception in section 40-30-217(a)(2) than was adopted by the Sawyer Court. Consequently, for the reasons that follow, I would deny the petitioner’s motion to reopen for failing to satisfy any of the procedural requirements.

1. New Scientific Evidence

The Post^Conviction Procedure Act of 1995 does not define “new scientific evidence” as used in Section 40-30-217(a)(2). It seems to me that two reasonable constructions of the phrase are possible. First, the language could be narrowly construed to mean only scientific evidence which either was not developed or was not in existence at the time of the petitioner’s *819original post-conviction proceeding. Alternatively, the language could be given a broader construction by including scientific evidence which, although in existence, was not available to the petitioner at the time of his original post-conviction proceeding by the exercise of due diligence.

I would give the statutory language the broader construction because I believe that it more nearly effectuates the intent of the General Assembly. While this legislation was being considered by that body, Chairman Frank Buck of the House Judiciary Committee remarked, “When some scientific test comes back and proves people to be innocent, there always ought to be some method by which that wrong is corrected. Always.” 99th General Assembly, 1st Sess., House, Tape # 2, H.B. 0001 (Mar. 29, 1995) (remarks of Rep. Buck).

Regardless of the construction given the phrase, such evidence must be admissible under the applicable Tennessee Rules of Evidence as required in Section 40-30-217(b) (“The factual information set out in the affidavit shall be limited to information which, if offered at an evidentiary hearing, would be admissible through the testimony of the affiant under the rules of evidence”) (emphasis added). The specific rules of evidence that govern the issue of admissibility of scientific proof in Tennessee are rules 7025 and 703.6 See, e.g., McDaniel v. CSX Transp., Inc., 955 S.W.2d 257, 264 (Tenn.1997). The rules together necessarily require a determination as to the scientific validity or reliability of the evidence.

See id. at 265. In short, evidence will be admissible if it is scientifically rehable or valid. Id. Several non-exclusive factors with which courts can determine reliability include the following:

(1) whether scientific evidence has been tested and the methodology with which it has been tested; (2) whether the evidence has been subjected to peer review or publication; (3) whether a potential rate of error is known; (4) whether ... the evidence is generally accepted in the scientific community; and (5) whether the expert’s research in the field has been conducted independent of litigation.

Id. (citing Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S.Ct. 2786, 125 L.Ed.2d 469 (1993)).

In my view, Van Tran’s latest I.Q. scores may not be presumed “new scientific evidence” without consideration of the validity or reliability of the test as required by our evidentiary rules and procedures. Although I am of the opinion that the petitioner is not entitled to an evidentiary hearing on his motion to reopen his post-conviction petition for the reasons contained in this dissent, if a hearing is to be held, then it is clear that the petitioner will be required to show by clear and convincing evidence that: (1) the WAIS-III test was not reasonably available to him at the time of his original post-conviction petition; (2) the updated version of the I.Q. test is qualitatively different from its predecessor *820such that this updated version is able to provide a more accurate measurement of the petitioner’s true intellectual abilities;7 and (3) the WAIS-III test provides a valid or reliable measurement of the petitioner’s I.Q.

2. The Meaning of “Actually Innocent of the Offense”

Assuming arguendo that the test results from the WAIS-III do constitute “new scientific evidence,” the petitioner must nevertheless demonstrate that these results establish his actual innocence “of the offense or offenses for which [he] was convicted.” The petitioner does not argue that his alleged mental retardation proves his innocence of his underlying crime of murder; rather, he urges this Court to adopt an expanded meaning of this phrase to include “actual innocence of or ineligibility for the death 'penalty.” As support, the petitioner cites the United States Supreme Court’s decision in Sawyer v. Whitley, 505 U.S. 333, 112 S.Ct. 2514, 120 L.Ed.2d 269 (1992), where the Court held that a prisoner could establish his actual sentencing innocence if the prisoner shows by clear and convincing evidence that, absent a constitutional error, no reasonable juror would have found the petitioner eligible for the death penalty under the applicable state law. Id. at 336.

The Proper Interpretation of Tennessee Code Annotated Section 10-30-217(a)(2)

If the petitioner’s broad definition of “actually innocent of the offense or offenses for which the petitioner was convicted” were adopted to include “innocent of capital punishment,” such a judicial construction would clearly and unduly expand the statute’s coverage beyond its intended scope. A cardinal rule of statutory construction is that courts should seek to ascertain and give effect to the intention and purpose of the General Assembly.

The General Assembly has explicitly qualified the term “actually innocent” in subsection (a)(2) with the clause, “of the offense or offenses for which the petitioner was convicted,” (emphasis added), leaving little doubt as to what the prisoner must demonstrate. The legislature is presumed to use each word in a statute deliberately, and the use of each word conveys some intent and has a specific meaning and purpose. Browder v. Morris, 975 S.W.2d 308, 311 (Tenn.1998). Indeed, there seems little question that the legislature applied subsection (a)(2) to mean that the prisoner must demonstrate actual innocence of the crime or crimes for which he was convicted and not merely his sentence. If the legislature had intended the petitioner’s broader definition, it would have included the language used in subsection (a)(3), which explicitly allows a prisoner to seek relief “from a sentence that was enhanced.” (emphasis added).

This interpretation is consistent with the repeated usage within the Post Conviction Procedure Act of the terms “offense,” “sentence,” and “conviction.” It is a general rule of statutory construction that where the same language is used repeatedly in the same context, it is presumed to contain the same meaning throughout the statute. Cf. Madison Suburban Util. Dist. v. Carson, 191 Tenn. 300, 305, 232 S.W.2d 277, 279 (1950). Significantly, these terms are used according to their ordinary and well-known meanings, as evidenced both by clarifying language in the statute and by their use both in the disjunctive and in *821the conjunctive. A prime example of our legislature using the terms “offense” and “sentence” according to their separate and distinct meanings is found in section 39-13-203(c), which requires the court to determine whether a defendant is mentally-retarded “at the time of the offense of first degree murder.” (emphasis added). Moreover, in subsection (d) of this same provision, if a defendant found guilty of first degree murder is also found to have been mentally retarded at the time of the offense, then the jury “shall fix the punishment in a separate sentencing proceeding.” See also Tenn. Code Ann. § 40-30-220(a) (requiring this Court to set an execution date upon affirming a conviction and sentence of death on direct appeal) (emphasis added); Tenn.Code Ann. § 40-30-203 (“Relief under this part shall be granted when the conviction or sentence is void or voidable because of the abridgement of any right guaranteed by the Constitution of Tennessee ....”) (emphasis added).

Accordingly, it is clear that the General Assembly intended the term “offense” to mean nothing more than the underlying crimes for which the petitioner was convicted. See, e.g., Hodge v. State, No. 03C01-9708-CR-00332, 1998 WL 283100, at *1 (Tenn.Crim.App. June 3, 1998) (rejecting defendant’s attempts to prove mental incompetency by introducing mental health records dating back to 1966 but only first discovered in 1996 as failing to establish “actual innocence” of the offenses for which the defendant was convicted). This interpretation fits most logically within the Act as a whole. It is difficult to conceive that the legislature would distort the ordinary definition of the term in one subsection of the statute but to clearly apply its plain meaning in all other provisions. Consequently, to prevent such an anomalous interpretation, subsection (a)(2) must be construed to require the petitioner to prove his actual innocence of the crimes for which he was convicted.

Sawyer v. Whitley and “Actual Innocence ”

The petitioner urges this Court to adopt the United States Supreme Court’s analysis in Sawyer v. Whitley, 505 U.S. 333, 338, 112 S.Ct. 2514, 120 L.Ed.2d 269 (1992), thereby expanding the definition of “actually innocent of the offense” in section 40-30-217(a)(2) to include “innocent of the death penalty.” Although we may look to federal interpretation of similar federal laws for guidance in enforcing our own statutes, we are neither bound by nor limited by federal law when interpreting our Post Conviction Procedure Act. Indeed, even assuming that the United States Supreme Court’s application of federal habe-as law is even remotely persuasive to this Court’s interpretation of the Tennessee Post Conviction Procedure statute, it is important to note at the outset that our General Assembly adopted a more narrow definition of the “actual innocence” exception in section 40-30-217(a)(2) than was relied on by the Sawyer Court.

In Sawyer, the defendant alleged that a fundamental miscarriage of justice would occur absent federal review of his abusive and successive federal habeas corpus claims on the merits. He argued that as a result of the ineffective assistance of counsel, certain evidence was withheld from the jury during the sentencing phase of his trial. Sawyer, 505 U.S. at 338. The defendant asserted that because this evidence was unconstitutionally kept from the jury, he was ineligible for the death penalty and therefore actually innocent of his capital sentence.

Addressing the meaning of “actual inno*822cence,”8 the Court concluded that “actual innocence” means “innocent of death” and is a “very narrow exception ... subject to determination by relatively objective standards.” Id. at 341. Nevertheless, the Court found the “actually innocent” exception inapplicable because the psychological evidence allegedly withheld from the jury did not relate to his guilt or innocence of the crime or to the aggravating factors found by the jury that made him eligible for capital punishment. Id. at 348-49.

However, under our General Assembly’s more narrow definition of the phrase “actually innocent,” a petitioner who files a motion to reopen a post-conviction petition based on new scientific evidence is required to demonstrate actual innocence of the underlying crimes for which he was convicted. Courts interpreting similarly worded statutes have also declined to expand the plain meaning of the language to allow a petitioner relief from a capital sentence. For example, federal habeas corpus law has been recently amended by the Antiterrorism and Effective Death Penalty Act of 1996, Pub.L. No. 104-132, § 105, 110 Stat. 1214 (amending 28 U.S.C. § 22559), to allow a prisoner to file a second habeas petition only if “newly discovered evidence ... would be sufficient to establish by clear and convincing evidence that no reasonable factfinder would have found the movant guilty of the offense.” Relying upon this Congressional amendment, the Seventh Circuit has denied a prisoner’s attempt to file a successive section 2255 motion for merely asserting his actual sentencing innocence rather than his innocence of his underlying crime. As the court explained,

The “actual innocence” exception of the prior law was judge-made, and so its contours were appropriately judge-fashioned and permissibly judge-expanded. The exception in the new law is graven in statutory language that could not be any clearer.... [T]he absence of any indication in the legislative history that “offense” was being used in some special sense different from its ordinary meaning [makes it] highly unlikely that Congress intended the word tp bear a special meaning.

Hope v. United States, 108 F.3d 119, 120 (7th Cir.1997); see also Greenawalt v. Stewart, 105 F.3d 1287, 1287-88 (9th Cir.1997).

Consequently, I reject the petitioner’s submission for a broader interpretation of the “actually innocent” exception as used by the General Assembly in section 40-30-217(a)(2). Because the petitioner has not met the standard demonstrating that the WAIS-III test results establish his actual innocence of the crime of first degree murder, I would deny his motion to reopen his post-conviction petition on procedural grounds alone.

*823 C. CONSIDERATIONS OF FUNDAMENTAL FAIRNESS

The majority holds that considerations of “fundamental fairness” dictate that the petitioner have a meaningful opportunity to raise his substantive constitutional claim. Declining to be bound by what it feels are the “technical” mandates of the Post-Conviction Procedure Act and Supreme Court Rule 28 governing waiver of issues, the majority has now given the petitioner an evidentiary hearing, even though the petitioner has never been statutorily entitled to receive this hearing in the first instance. Nevertheless, the majority grants the petitioner an evidentiary hearing so as to provide him “due process of law.” I disagree because in my view, the petitioner has already been fully afforded due process of law.

Until today’s unfortunate change in the law, no defendant has previously possessed a federal or state constitutional right to collaterally attack his or her conviction in state court. Instead, as this Court has often recognized, the “state may erect reasonable procedural requirements for triggering the right to [such] an adjudication.” See Burford v. State, 845 S.W.2d 204, 207-08 (Tenn.1992). Indeed, the state may even “terminate a [post-conviction] claim for failure to comply with a reasonable procedural rule without violating due process rights.” Id. at 208 (citing Logan v. Zimmerman Brush Co., 455 U.S. 422, 437, 102 S.Ct. 1148, 71 L.Ed.2d 265 (1982)). The only due process protection afforded a defendant in the post-conviction context is that a procedural rule cannot deny the defendant an “ ‘opportunity to be heard at a meaningful time and in a meaningful manner.’ ” See House v. State, 911 S.W.2d 705, 711 (Tenn.1995) (quoting Mathews v. Eldridge, 424 U.S. 319, 333, 96 S.Ct. 893, 47 L.Ed.2d 18 (1976)) (emphasis in original). So long as the policies reflected in a procedural requirement afford the defendant a fair and reasonable opportunity to present a claim, then the defendant may not assert that his due process rights have been violated. See Burford, 845 S.W.2d at 208.

I cannot agree that considerations of fundamental fairness dictate that we bypass the statutory requirements for obtaining a hearing under the Post-Conviction Procedure Act. First, the petitioner cannot establish his substantive eligibility for a hearing under any subsection of Tennessee Code Annotated section 40-30-217(a), and I know of no authority that permits a court to reopen a post-conviction petition when the defendant does not meet any of the statutory criteria necessary for reopening. Indeed, I find it somewhat anomalous to conclude, as the majority apparently does today, that due process of law somehow entitles the petitioner an opportunity to reopen his post-conviction petition, even though he is not entitled to such a hearing under the statute, and even though due process would not compel the legislature to provide for such a hearing in the first instance. Given the sweeping nature of the majority’s new “fundamental fairness” doctrine, I am concerned whether the statutory requirements to receive a post-conviction hearing retain any meaning at all.

But even if due process were to allow a hearing when the petitioner did not meet the statutory requirements for obtaining a hearing, I disagree that considerations of fundamental fairness are applicable. First, the petitioner has not been denied a meaningful opportunity to be heard on his substantive constitutional claim. Significantly, at his 1997 post-conviction hearing, the petitioner was not restricted by the trial court from raising the substantive constitutional issue, and the record con*824tains no indication that he tried to raise this issue but was inappropriately limited in his ability to present evidence to support his claims for relief. Indeed, though not constitutionally required, the petitioner was also afforded the assistance of counsel in asserting and litigating his claims. As such, the petitioner received everything that “fundamental fairness” requires him to receive: the opportunity to be heard on his claim. The majority’s holding to the contrary notwithstanding, the petitioner’s own failure to present the claim as a basis for relief is not tantamount to his being denied the opportunity to present the claim.

Second, unlike all of our previous cases invoking the “fundamental fairness” doctrine in the post-conviction context, the petitioner’s failure to raise the substantive constitutional claim, was not due to circumstances beyond his own control. In previous cases where this Court has granted a post-conviction hearing based upon due process grounds, the defendant was confronted with circumstances beyond his control that prevented him from asserting a claim. See Williams v. State, 44 S.W.3d 464 (Tenn.2001); State v. Nix, 40 S.W.3d 459 (Tenn.2001); Seals v. State, 23 S.W.3d 272 (Tenn.2000); Watkins v. State, 903 S.W.2d 302 (Tenn.1995); Burford v. State, 845 S.W.2d 204 (Tenn.1992). In this case, however, the ability to present and litigate the substantive constitutional issue was entirely within the petitioner’s own control. Consequently, I disagree with the majority that “fundamental fairness” now requires that the petitioner be given a second bite at this constitutional apple.

II. SUBSTANTIVE CONSTITUTIONAL ANALYSIS

Nevertheless, even granting the dubious propositions that the substantive constitutional issue is properly before the Court and that the General Assembly intended for the meaning of “actual innocence of the offense” to include ineligibility for the death penalty, the petitioner must still show that his alleged mental condition places him among a class of persons who are ineligible to receive a capital sentence. To this end, the petitioner advances two arguments: (1) that Tennessee Code Annotated section 39-13-203, which proscribes the sentencing of mentally retarded persons to death, should be applied retroactively to prohibit his execution, and (2) that both the Eighth Amendment to the United States Constitution and Article I, section 16 of the Tennessee Constitution bar his execution as cruel and unusual punishment.

As a threshold matter, I agree with the majority that section 39-13-203 is not properly applied retroactively to reheve this defendant of his capital sentence. Apart from questions as to the constitutional authority of the General Assembly to retroactively relieve a defendant of a final and valid sentence, cf. State ex rel. v. McClellan, 87 Tenn. 52, 55, 9 S.W. 233, 234 (1888), I find no evidence that clearly demonstrates the legislature’s intent to have this statute operate retroactively. Consequently, if the petitioner is entitled to have his post-conviction petition reopened, it can only be because the Constitution of the State of Tennessee forbids his execution.10

*825 A. THE NATURE OF THE CONSTITUTIONAL ISSUE BEFORE THE COURT

Initially, it is of vital importance to understand the precise constitutional question before the Court. Contrary to the majority’s formulation, the issue in this case is not simply whether the Tennessee Constitution prohibits the execution of mentally retarded persons. Under some well-settled circumstances, it already does, and I do not understand these well-settled circumstances to be at issue here.

This Court has previously held that the Constitution prohibits the execution of a defendant within “the borderline mentally retarded range” if, because of that mental condition, the defendant lacks substantial capacity either to appreciate the wrongfulness of his conduct or to conform his conduct to the requirements of law. In State v. Laney, 654 S.W.2d 383 (Tenn.1983), this Court, speaking through then Justice Dro-wota, denied the defendant’s challenge to his capital sentence on the ground that the fact of his low I.Q. rendered the sentence cruel and unusual. In denying that the mere fact of low intelligence alone rendered a capital sentence unconstitutional, the Court held that so long as the mental condition did not affect the defendant’s capacity either to appreciate the wrongfulness of his conduct or to conform his conduct to the requirements of law, the law would “hold [that] person accountable for his actions.” Id. at 389 (citing Graham v. State, 547 S.W.2d 531, 543 (Tenn.1977)). This Court then upheld Laney’s capital sentence upon finding that his I.Q. of seventy-two did not affect his “mental capability to plan, commit and attempt to cover up his involvement in the crime.” Id.

As evidenced by Laney, the law is already settled that the Constitution of the State of Tennessee forbids the execution of a mentally retarded defendant under certain circumstances, such as where a defendant’s mental condition displaces the following capacities: (1) the cognitive capacity to appreciate the consequences of certain action, (2) the moral capacity to appreciate the wrongfulness of certain action, or (3) the volitional capacity to behave in a lawful manner. See also Penry v. Lynaugh, 492 U.S. 302, 338, 109 S.Ct. 2934, 106 L.Ed.2d 256 (1989) (O’Connor, J.) (stating that the Eighth Amendment does not bar execution, unless a defendant’s mental condition affects his or her cognitive, volitional, and moral capacities).11 However, the majority today expands this prohibitional bar well beyond the holding of Laney. Instead of focusing its rationale on the cognitive abilities of the individual defendant, the majority now expands prior law to render all mentally retarded persons, despite the actual cognitive, moral, or volitional abilities possessed by the individual defendant, ineligible for *826capital punishment.12

As such, the issue before the Court is not simply whether the Constitution prohibits the execution of the mentally retarded. Under some circumstances, it does, and it always has. Instead, the real issue in this case is whether the Tennessee Constitution now also forbids the execution of someone who suffers from a mental condition, but whose condition does not affect his or her cognitive, moral, or volitional capacities to commit capital murder.

The majority’s decision is a broad expansion of existing law, and one that I believe is unwarranted and will lead to injustice in individual cases. Instead, I would hold that the Constitution continues to permit the punishment of a defendant who has the cognitive capacity to appreciate that certain action will lead to the death of others, who has the moral capacity to appreciate the wrongfulness of murder, and who otherwise has the volitional capacity to behave in a lawful manner. For the reasons given below, I respectfully dissent from the conclusion that the Tennessee Constitution prohibits the petitioner’s execution, or, consequently, that he has shown that he is “actually innocent of the offense” under section 40-30-217(a)(2).

B. APPLICATION OF ARTICLE I, SECTION 16

Any interpretation of a constitutional provision necessarily begins with its language. Article I, section 16 of the Tennessee Constitution provides that “excessive bail shall not be required, nor excessive fines imposed, nor cruel and unusual punishments inflicted.” We have previously recognized the textual similarity of this provision to that of the Eighth Amendment, and as such, we have adopted the analysis used by the United States Supreme Court in Gregg v. Georgia, 428 U.S. 163, 173, 96 S.Ct. 2909, 49 L.Ed.2d 859 (1976), for determining whether a punishment is cruel and unusual under the Tennessee Constitution. See State v. Black, 815 S.W.2d 166, 189 (Tenn.1991). According to this standard, the petitioner is entitled to a reduced sentence only if he can show that his punishment is cruel and unusual in light of three factors: “First, does the punishment for the crime conform with contemporary standards of decency? Second, is the punishment grossly disproportionate to the offense? Third, does the punishment go beyond what is necessary to accomplish any legitimate penological objective[?]” Id. (citations omitted). I disagree that the petitioner has successfully met his burden under any of these three criteria.13

1. Penological Objectives Served by the Punishment

Taking these inquiries in reverse order, the legitimate penological objectives of capital punishment in this state, retribution and deterrence, see, e.g., State v. Keen, 31 S.W.3d 196, 217 (Tenn.2000), are not undermined so long as the defendant possesses the capacities to appreciate that *827certain action will lead to the death of others, to appreciate the moral wrongfulness of murder, and to behave in a lawful manner. While the mental condition of some offenders may significantly impair these capacities, I disagree that this conclusion invariably follows in all cases. Consequently, where these capacities remain largely unaffected by the defendant’s mental condition, the Constitution cannot bar capital punishment on the ground that no penological goal supports it.

Retribution and Moral Blameworthiness

As for the former objective, the retributive value of capital punishment is closely tied to the defendant’s culpability, as evidenced by the Supreme Court’s statement that retribution is an appropriate consideration so long as the punishment is tailored to the defendant’s “personal responsibility and moral guilt.” See Enmund, 458 U.S. at 801. As one member of the present majority has noted with regard to retribution in the capital context, this justification for punishment may be characterized as “the need to offset a criminal act by a punishment of equivalent ‘moral quality.’ ” See Van Tran, 6 S.W.3d at 277 (Birch, J., dissenting) (internal quotation marks omitted). When viewed in this light, the retributive aspect of capital punishment “is an expression of society’s moral outrage at particularly offensive conduct. This function may be unappealing to many, but it is essential in an ordered society that asks its citizens to rely on legal processes rather than self-help to vindicate their wrongs.” Gregg, 428 U.S. at 183.

The majority takes substantial issue with the notion that some mentally retarded offenders can possess any moral culpability for their criminal actions, and it holds that the mere status of mental retardation is sufficient to render a defendant utterly incapable of acting with the level of personal culpability that would justify a capital sentence. Indeed, while the majority notes that mental retardation exists in several degrees of severity, ranging from mild to profound, it makes no practical distinction between these degrees in its analysis of moral blameworthiness. Taken to its logical extreme, the majority’s rationale posits that the mere label of mental retardation is sufficient to remove any notion that a defendant can possibly be morally blameworthy. This conclusion cannot invariably follow, because it ignores the differing mental capacities, life experiences, and general abilities possessed by individuals within the majority’s large and diverse class of persons.

Directly contradicting conclusions similar to those advanced by the majority in this case, Justice O’Connor examined the record in Penry — a record, incidentally, that was more fully developed and supplemented than the record in this case — and concluded the following as to the abilities of this class of defendants:

Mentally retarded persons are individuals whose abilities and experiences can vary greatly.... In addition to the varying degrees of mental retardation, the consequences of a retarded person’s mental impairment, including the deficits in his or her adaptive behavior, “may be ameliorated through education and habilitation.” Although retarded persons generally have difficulty learning from experience, some are fully “capable of learning, working, and living in their communities.” In light of the diverse capacities and life experiences of mentally retarded persons, it cannot be said on the record before us today that all mentally retarded people, by definition, can never act with the level of culpability associated with the death penalty.

*828492 U.S. at 338-339 (citations omitted) (emphasis added).

Therefore, while the majority’s conclusions may follow in some, if not many, cases, these generalities are overbroad at best, and, at worst, they can lead to manifest injustice in individual cases. Indeed, if one needs proof of the veracity of this proposition, one should look no farther than to the petitioner’s case before us now. Assuming that the petitioner falls within the majority’s new class of capitally ineligible defendants, a tragic error will occur if the majority’s assumptions as to the general abilities of this class are given effect in this case.

Let only three facts be submitted for candid and objective consideration: First, the petitioner has not alleged, either in his petition or through accompanying affidavits, that his mental condition affected his ability to understand what would happen if he pulled the trigger of a loaded pistol. In fact, no evidence has ever suggested that Van Tran was unaware that people could die if shot in the throat and head, as was the ease with Kai Yin Chuey. Instead, the petitioner’s original description of the events provides considerable evidence that he was acutely aware of the consequences of his deadly actions, and a different score on an updated I.Q. test simply does not change this conclusion.

Second, the petitioner has not alleged, either in his petition or through accompanying affidavits, that his mental condition affected his ability to understand that it was morally wrong to murder or that it otherwise affected his ability to kill with premeditation or deliberation. Van Tran’s awareness of the moral wrongfulness of his conduct can be seen not only in his six-month flight and evasion of authorities, but also from the fact that he knowingly gave a false name to police officers upon his arrest in Houston. Moreover, no evidence from any proceeding has ever suggested that Van Tran was somehow incapable of forming an intent to kill. To the contrary, two members of the present majority closely reviewed the record in 1993 and specifically found that the murder of Kai Yin Chuey “involved the intentional and senseless killing of a helpless, elderly victim during a robbery.” Van Tran, 864 S.W.2d at 482 (emphasis added). I agree with their assessment.

Third, and finally, the petitioner has not alleged, either in his petition or through accompanying affidavits, that his mental condition affected his ability to behave in a lawful manner or that it otherwise compelled him to execute Kai Yin Chuey. Indeed, before his horrific criminal episode, he apparently had no criminal record, and I am aware of no similar conduct since that day in 1987. Surely, the majority must concede" that a different score on a revised I.Q. test does not change the fact that Van Tran is capable of behaving in a lawful manner.

Given that Van Tran has not even alleged that his cognitive, moral, or volitional capacities were affected by his mental condition, it is difficult to understand that this Court could conclude that he is somehow not morally blameworthy for his crimes. In fact, it is precisely because he possesses these capacities that he is morally blameworthy for the murder of Kai Yin Chuey. While I agree that in some cases mental retardation will substantially affect a defendant’s cognitive, moral, or volitional capacities to such an extent that capital punishment would be unconstitutional, Van Tran’s case illustrates perfectly that the offender’s mental condition does not invariably affect these processes. As to these offenders, then, retribution remains a valid and material penological justification sup*829porting capital punishment.14

Because I am able to assert that the petitioner has always possessed the cognitive, moral, or volitional capacities to commit first degree murder, the majority posits that I have somehow engaged in an improper “fact-finding exercise of reviewing this case.” My conclusions regarding the petitioner’s relative capacities were not found by me on some “fact-finding exercise”; they are implicit in the jury’s verdict and sentence of death. I am fully confident that these findings are correct, because the petitioner has never contested their veracity in any proceeding, not even before this Court today. Moreover, the record of that case was carefully reviewed by the Court of Criminal Appeals and by this Court, and each court necessarily concluded that the petitioner did possess the necessary cognitive, moral, and volitional capacities to commit first degree murder, as evidenced by their affirmance of his convictions. Therefore, while the majority has taken a different approach to constitutional adjudication, I am certain that my uncontested assertions as to the petitioner’s cognitive, moral, and volitional capacities are the result of legitimate, and constitutionally accepted, methods of appellate review.

Deterrence of Intentional or Reckless Conduct

With regard to deterrence as an objective of capital punishment, the majority notes that mental retardation may prevent a defendant from fully appreciating the consequences of actions. Again, while this proposition may be true in some cases, I see no evidence that it is invariably true. We have recently explored in detail how deterrence is affected by sentencing behavior, and we recognized that punishment can work to deter intentional, knowing, or reckless conduct. See State v. Hooper, 29 S.W.3d 1, 11 (Tenn.2000); see also En-mund, 458 U.S. at 798-99 (“We are quite unconvinced, however, that the threat that the death penalty will be imposed for murder will measurably deter one who does not kill and has no intention or purpose that life will be taken.”); Tison v. Arizona, 481 U.S. 137, 158-59, 107 S.Ct. 1676, 95 L.Ed.2d 127 (1987) (expanding the culpability requirements of Enmund to include “major participation in the felony committed, combined with reckless indifference to human life”). Therefore, where the defendant’s mental condition does not affect his or her capacity to intend that death follow from certain actions, then deterrence remains permissible justification in the capital context. Indeed, deterrence would also be a permissible justification even if the victim’s death was only the result of reckless conduct.

Even assuming that the petitioner possesses an I.Q. of sixty-five, however, no evidence has ever been presented that he was incapable of forming an intent to kill or was otherwise unable to murder with premeditation and deliberation. As I acknowledged earlier, this Court has previously found that the murder of Kai Yin Chuey was the result of a specific intent to kill. See Van Tran, 864 S.W.2d at 482. Moreover, the petitioner’s major participation in the felony, even if not the result of a specific intent to kill, was certainly the result of knowing or extremely reckless conduct. With good reason, the law has always supposed that these types of actions can be deterred by punishment. Therefore, when the defendant’s mental condition does not prevent him or her from appreciating that death would follow from *830certain action, then deterrence certainly remains a legitimate penological goal in the capital context.

Inherent Contradictions in the Majority’s Analysis of Penological Justifications

To avoid the impression that its analysis of penological justifications is without foundation, the majority employs contradictory statements to first justify its holding and then to respond to my review of that holding. For example, the majority first asserts that retribution cannot justify capital punishment because the condition of mental retardation always affects the defendant’s ability “to appreciate the concept of blameworthiness,” and will “render a mentally retarded offender unable to understand that certain repercussions flow from certain [acts].” In the same vein, the majority states that deterrence is an improper justification because mentally retarded persons, as a class, are “not able to weigh the cost of the criminal act, the consequences of the punishment, or the benefits of alternatives.” However, in response to my criticisms of its holding, the majority states, in contradiction to its earlier conclusions, that “we do not hold that the conviction and punishment of a mentally retarded defendant never achieves valid penological goals.” Consequently, the very conclusion that the majority went through great effort to dismiss — that retribution and deterrence are not valid pe-nological goals with respect to mentally retarded offenders — is revived when necessary to respond to the obvious shortcomings of its holding.

Given the majority’s analysis of this issue, I am left to wonder which conclusion now represents the current state of the law. Notably, if the former conclusion— that mentally retarded offenders, by definition, cannot be morally blameworthy or be deterred from unlawful conduct — is the preferred conclusion, then all punishment, capital or otherwise, must necessarily be unlawful as well. After all, how can any punishment be acceptable if the offender’s mental condition invariably infects his or her moral blameworthiness and ability to appreciate consequences of action? 15 honey suggests that no such punishment could ever be valid, and as such, the majority’s faint attempt to limit its holding to capital punishment alone is suspect indeed.

On the other hand, if the latter conclusion — that at least some offenders in this class can distinguish between right and wrong and appreciate the consequences of action — represents the new state of the law, then absolutely no rationale warrants a categorical exemption from any punishment based solely on the fact of a mental condition. Instead, the punishment determination should be made on an individualized basis, paying close attention to the effect that the offender’s condition has upon his or her particular cognitive, moral, and volitional capacities, just as I have advocated today. Nevertheless, the majority maintains its categorical exemption even in the face of its admission that retribution and deterrence can serve as legitimate penological justifications in this context, at least for some offenders.

2. The Substantive Proportionality of the Petitioner’s Capital Sentence

The next inquiry is whether a sentence of death is a proportionate penalty to the *831crime of first degree murder. In State v. Harris, 844 S.W.2d 601 (Tenn.1992), this Court adopted a two-pronged inquiry, taken substantially from Justice Kennedy’s concurring opinion in Harmelin v. Michigan, 501 U.S. 957, 996, 111 S.Ct. 2680, 115 L.Ed.2d 836 (1991), to determine the substantive proportionality of punishment under Article I, section 16. The first inquiry under this test is to compare the sentence with the crime committed to determine whether the “comparison leads to an inference of gross disproportionality.” If an inference so arises, then “the analysis proceeds by comparing (1) the sentences imposed on other criminals in the same jurisdiction, and (2) the sentences imposed for commission of the same crime in other jurisdictions.” Harris, 844 S.W.2d at 603.

In this case, satisfaction of the first inquiry validates the substantive proportionality of the death penalty, because, as this Court has acknowledged countless times, capital punishment is not disproportionate to the offense of first degree murder. See, e.g., Black, 815 S.W.2d at 190 (“[WJhen a life has been taken deliberately by the offender, we cannot say that the punishment is invariably disproportionate to the crime. It is an extreme sanction, suitable to the most extreme of crimes.” (quoting Gregg, 428 U.S. at 187)). Contrary to the majority’s rationale, the mental condition of the defendant found guilty of first degree murder is irrelevant to whether the punishment is substantively proportional to that crime in the abstract, unless that condition leaves the defendant without sufficient cognitive, moral, or volitional capacities to commit the capital crime in the first place. See State v. Middlebrooks, 840 S.W.2d 317, 339 (Tenn.1992) (stating that substantive proportionality is concerned “only with the imposition of capital punishment for the crime of [capital] murder in the abstract”). As I stated earlier, I am unpersuaded that all defendants within the majority’s newly formed class are inherently without the cognitive, moral, and volitional capacities to commit capital murder. As to these persons, then, capital punishment remains presumptively proportionate to the crime of first degree murder and, hence, it cannot constitute cruel and unusual punishment for the reason that it is abstractly disproportionate.

Considerations of the Criminal Justice System

As further support for its holding that a capital sentence within this context is invariably disproportionate, the majority notes that the mental condition of some defendants may hamper their ability to assist counsel or to make decisions about the course of their defense. The majority further notes that these defendants are less likely to withstand police coercion or pressure, thereby making them particularly vulnerable to involuntary confessions. Presumably, then, because of these factors, the majority concludes that capital punishment in this circumstance constitutes cruel and unusual punishment under Article I, section 16.

I do not necessarily doubt the veracity of the majority’s premises as applied to some defendants, but these premises are simply not relevant to the substantive analysis of punishment under Article I, section 16. The constitutionality of the punishment under Article I, section 16 is considered in the abstract, separate and apart from the other aspects of the criminal justice system. Cf. Middlebrooks, 840 S.W.2d at 339. If a defendant with mild mental retardation encounters difficulty in the system, other constitutional protections are present to prevent a manifest *832injustice from occurring.16 The encountering of any such difficulties, however, has never been considered to render the ultimate punishment unconstitutional. Either a punishment is cruel and unusual, or it is not, and I cannot agree that the majority’s perceived shortcomings in the criminal justice system will render a punishment substantively disproportionate under Article I, section 16.

3. Contemporary Standards of Punishment

Finally, in examining the remaining prong of the Black test, I disagree that the petitioner has carried his burden in demonstrating that contemporary standards of punishment in this State have so drastically changed since our decision in Laney that it is now unconstitutional to execute those defendants whose mental condition does not affect their cognitive, moral, or volitional capacities. This final examination essentially assesses the “contemporary values [in Tennessee] concerning the infliction of a challenged sanction.” See State v. Howell, 868 S.W.2d 238, 264 (Tenn.1993) (quoting Gregg, 428 U.S. at 173). This assessment “does not call for a subjective judgment,” Gregg, 428 U.S. at 173, and courts look to a variety of “objective indicia that reflect the public attitude toward a given sanction,” such as legislative enactments, jury sentencing behavior, prosecutors’ decisions, and opinion polls.

In examining these contemporary values, however, “[i]t is not the role of this Court to superimpose personal morality in difficult issues, or to act as a good reflex of a democratic society.” Black, 815 S.W.2d at 190 (internal quotations and citation omitted).

Evidence of Contemporary Values in Tennessee

Although a defendant always has the burden of proving that a societal consensus concerning the punishment at issue has emerged, see Stanford v. Kentucky, 492 U.S. 361, 373, 109 S.Ct. 2969, 106 L.Ed.2d 306 (1989), the petitioner in this case has failed to satisfactorily demonstrate that Tennesseans have arrived at a consensus against executing persons whose mental condition does not affect their cognitive, moral, or volitional capacities to commit murder. The petitioner has brought forward no evidence that juries regularly fail to return a capital sentence against persons whose mental condition does not affect their cognitive, moral, or volitional capacities to commit murder. He has not shown that prosecutors routinely fail to seek the death penalty in eligible cases when the defendant has a mental condition that does not affect his or her cognitive, moral, or volitional capacities to commit murder. Furthermore, the petitioner has cited no opinion polls in this state that demonstrate that the people of this State *833overwhelmingly believe that it is morally wrong to execute persons whose mental condition does not affect their cognitive, moral, or volitional capacities to commit murder.

In fact, the only “objective indicium” presented by the petitioner that Tennesseans have reached a definitive consensus on this issue is the presence of Tennessee Code Annotated section 39-13-203. As the majority correctly notes, the presence of a statute permitting or prohibiting a particular form of punishment is a strong indicator of the public views regarding its use. However, just as the presence of a statute permitting a punishment cannot be viewed in isolation as constitutionally sanctioning the practice, Black, 815 S.W.2d at 188, neither can the isolated presence of a statute prohibiting a punishment also mean that the Constitution now forbids its use.

Importantly, the United States Supreme Court has rejected the view that a single statute, without other evidence of contemporary values, demonstrates a consensus among those represented sufficient to command constitutional change. One year before Penry was decided, the Congress of the United States enacted a provision that specifically provided that “[a] sentence of death shall not be carried out upon a person who is mentally retarded.” See 21 U.S.C. § 848(0 (1988). Although Congress presumably acts with the full voice and authority of the nation as a whole— and therefore presumably reflects the contemporary values and norms of the nation — the Penry Court did not find that this statute evidenced a national consensus against executing mentally retarded persons. See Penry, 492 U.S. at 304. Instead, the Court gave the mere presence of this national statute virtually no weight at all, and it continued to look elsewhere for evidence of a national consensus on the issue.

In this case, however, the majority takes an approach that is curiously contrary to the well-reasoned analysis taken in Penry. Armed only with the presence of a single statute on the issue, the majority declares that Tennesseans have reached a consensus sufficient to justify constitutional change. I simply cannot agree. When a punishment furthers legitimate goals of punishment, and when that punishment is proportional to the offense and to the offender, the mere presence of a statute restricting the use of that punishment cannot be sufficient evidence of the punishment’s substantive constitutionality. Indeed, because the majority has no evidence of the public judgment in Tennessee other than the presence of this statute, the practical effect of its holding in this case is to elevate that statutory text to constitutional commandment. In so doing, the majority has essentially bestowed upon the General Assembly the power to constitutionally prohibit punishment under Article I, section 16 through the mere enactment of a single statute. This reasoning is flawed, however, because it ignores the constitutional reality that the people have not given the General Assembly the ultimate power to alter or amend their Charter of government. Instead, the people have expressly reserved that power for themselves. See Tenn. Const, art. I, § 1; art. XI, § 3.

Through the exercise of its legislative power, the General Assembly is always free to prohibit any type of punishment that it deems inappropriate. Indeed, because the legislative power of the state includes the power to define punishment for crime, see Bibbs v. State, 162 Tenn. 646, 649, 39 S.W.2d 1024, 1025 (1931); see also Harris, 844 S.W.2d at 602, the Constitution itself confers upon the General As*834sembly broad discretion to permit and proscribe different types of punishment. In exercising the legislative power to enjoin a particular punishment, however, it has never been understood that the General Assembly has also effectively declared that punishment to be unconstitutional and, therefore, outside its power to re-enact or amend at a later date should it so desire. To the extent that the majority’s holding today, which relies solely upon the presence of a single statute to evidence the public’s constitutional judgment, now permits this conclusion to follow, I believe that it represents an unconstitutional interference with the legislative power to fix and define punishment, see Tenn. Const, art. II, § 2, and I cannot join in its decision.

Use of Other Cognitive Standards in Tennessee

Ultimately, I am uncertain as to why the majority holds that the mere fact of mental retardation is determinative of the constitutional inquiry, rather than looking to the effect that the mental condition has upon the defendant. This holding is fundamentally at odds with the law, either constitutional or otherwise, in virtually all other areas in this state. Surely, these other standards must be of some persuasive force to show that Tennesseans have not reached a consensus that the cognitive, moral, or volitional capacities of a defendant are now irrelevant to his or her punishment. Though ignored by the majority, the following is a brief list of examples in which the focus of similar inquiries is upon the effect of the defendant’s mental condition, and not upon the mere fact of the defendant’s condition:

The mere fact of mental retardation does not prevent a defendant’s impending execution. Instead, a court must decide whether the mental condition affects the defendant’s ability to understand the fact of the impending execution and the reason for it. See Van Tran, 6 S.W.3d at 266.

The mere fact of mental retardation does not prevent a defendant from being found competent to stand trial. Instead, a court must decide whether the mental condition affects the defendant’s ability to understand the nature and object of the proceedings, to consult with counsel, or to assist in the preparation of his or her defense. See State v. Blackstock, 19 S.W.3d 200, 205 (Tenn.2000).

The mere fact of mental retardation does not prevent a defendant from pleading guilty. Instead, a court must decide whether the mental condition affects the defendant’s ability to understand the proceedings and to understand the significance and consequences of a particular decision. See Moten v. State, 935 S.W.2d 416, 420 (Tenn.Crim.App.1996) (citing and quoting Godinez v. Moran, 509 U.S. 389, 401 n. 12, 113 S.Ct. 2680, 125 L.Ed.2d 321 (1993)).

The mere fact of mental retardation does not prevent a defendant from waiving Miranda rights. Instead, a court must decide whether the mental condition affects the defendant’s ability to waive those rights intelligently. See State v. Benton, 759 S.W.2d 427, 431 (Tenn.Crim.App.1988) (“We recognize that no single factor such as age, education, or even mental retardation is conclusive on the waiver issue.” (emphasis added)).

The mere fact of mental retardation does not prevent a person from being a witness. Instead, a court must decide whether the mental condition affects the witness’s ability to understand the nature of the oath and testify truthfully. See State v. Johnson, 685 S.W.2d 301, 305 (Tenn.Crim.App.1984).

*835Indeed, the mere fact of mental retardation does not prevent a defendant from being found guilty of first degree murder. Instead, a court reviewing the sufficiency of the evidence must decide whether the mental condition affected the defendant’s ability to kill with intent or with premeditation and deliberation. See State v. Brown, 836 S.W.2d 530, 537 (Tenn.1992).

Given that all these circumstances focus upon the effect of mental retardation as the relevant characteristic, it is indeed difficult to understand the majority’s holding that the mere fact of retardation will prevent a defendant from being eligible for capital punishment. Although the General Assembly is free to enact a statute imposing such a per se prohibition if it so desires, the Court has now fashioned a new, broad constitutional rule where no such rule has previously existed and where no clear evidence exists to suggest that there is a contemporary societal consensus mandating its recognition. Indeed, only time will tell whether the majority’s new constitutional holding founded upon generic assumptions regarding the abilities of all mentally retarded persons will work profound changes in other areas of constitutional law as well.

Evidence of Contemporary National Values

Because the majority has rejected the notion that it is interpreting the Eighth Amendment in this case, I am uncertain why the majority tries to divine a contemporary national standard on this issue. Just as “American conceptions of decency” are dispositive in the Eighth Amendment context, see Stanford, 492 U.S. at 369 n. 1 (emphasis in original), only that evidence reflecting Tennessee’s contemporary values should be relevant to the analysis under Article I, section 16. Nevertheless, even taking this questionable premise as true, I disagree that any national consensus has emerged that would warrant a change in the meaning of Tennessee’s Constitution. As a simple count from the majority’s tally reveals, less than half of all the death penalty jurisdictions have legislatively prohibited the execution of mentally retarded defendants.17 The standards by which these prohibitions are measured *836are not uniform, and at least one jurisdiction bars such executions only when the defendant’s subaverage intellectual functioning “substantially impairs one’s capacity to appreciate the criminality of one’s conduct or to conform one’s conduct to the requirements of law.” See Kan. Stat. Ann. § 21^4623(e) (1995). In my mind, the majority’s evidence of a nationwide consensus is simply insufficient to legitimately conclude that Article I, section 16 constitutionally mandates a categorical prohibition on such executions in this state.

CONCLUSION

In summary, I cannot agree that the petitioner has satisfied any requirements for reopening his post-conviction petition. The petitioner is not constitutionally entitled to reopen his post-conviction petition, and as such, he may do so only when the statute permits its reopening. I would first find that the constitutional issue presently addressed by the Court has been previously waived by the petitioner and is beyond the authority of this Court to review. Because we also lack the authority to excuse the petitioner’s waiver, we are likewise without authority to address the petitioner’s constitutional claim on its merit as the majority has done today. Accordingly, I would hold that the substantive constitutional issue should be dismissed, thereby prohibiting the petitioner from filing a future motion to reopen under subsection (a)(1).

I would also find that the petitioner’s claim to reopen fails under Tennessee Code Annotated section 40-30-217(a)(2). Because this Court has not previously considered the proper standard governing the admissibility of “new scientific evidence,” it is inappropriate to assume that the WAIS-III qualifies as such without further inquiry. Moreover, I disagree with the petitioner’s interpretation of the language “actual innocence of the offenses for which he was convicted” to include innocence of, or ineligibility for, the death penalty. Such an interpretation ignores the plain meaning of the words themselves; it ignores that the General Assembly has distinguished between the words “offense” and “sentence” in the same statute; and it ignores that the legislature has never used the term “offense” to include the sentence imposed for the underlying crime. Consequently, I am unable to join the majority’s decision permitting the petitioner to reopen his post-conviction petition.

Perhaps most importantly, however, I disagree that the Constitution of the State of Tennessee bars the petitioner’s execution. Contrary to the majority’s holding, Article I, section 16 of the Tennessee Constitution permits the execution of a defendant whose mental condition does not affect the defendant’s cognitive capacity to appreciate that certain action will lead to the death of others, the defendant’s moral capacity to appreciate the wrongfulness of murder, or the defendant’s volitional capacity to behave in a lawful manner. Capital punishment in this context serves legitimate penological goals, because not all defendants in the majority’s class are invariably incapable of intending to commit a capital offense, and the punishment is proportional to the crime of first degree murder. Moreover, I have not found sufficient evidence to suggest that the public judgment in Tennessee is categorically against the execution of individuals, who, while possessing mild mental retardation, also possess the cognitive, moral, and volitional capacities to commit first degree murder.

The petitioner in this case has not alleged, either in his petition or through accompanying affidavits, that his mental condition affected his cognitive capacity to appreciate that certain action would lead to the death of Kai Yin Chuey, his moral *837capacity to appreciate the wrongfulness of murder, or his volitional capacity to behave in a lawful manner. Instead, he seeks to set aside his capital sentence based on the mere fact of his mental condition without regard to its effect. This reason is simply insufficient in my mind to show the petitioner’s “actual innocence of the offense” under Tennessee Code Annotated section 40-30-217(a)(2), even if the majority’s interpretation of this provision is appropriate.

For these reasons, I respectfully dissent. Furthermore, I am authorized to state that Justice Holder joins in this dissenting opinion.