James Stafford appeals the district court’s imposition of two consecutive four-year sentences under 18 U.S.C. §§ 1510 (obstruction of criminal investigations) and 1952 (interstate travel in aid of racketeering enterprises). Stafford contends that Congress did not intend to punish his conduct under both statutes and that the district court therefore should have vacated one of the sentences. We affirm.
BACKGROUND
Stafford pled guilty to Counts 21 and 22 of the indictment. Count 22 charged that he violated 18 U.S.C. § 1510 by “willfully endeavoring] by means of bribery” to prevent a witness in Louisiana from informing the FBI of certain federal criminal offenses. Count 21 charged that Stafford violated 18 U.S.C. § 1952 (“Travel Act”) by (1) traveling from California to Louisiana with the intent to commit an unlawful activity, namely the offense charged in Count 22; and (2) actually committing that offense.
The district court sentenced Stafford to four years confinement on each count, with the sentences to run consecutively. Stafford moved the court pursuant to Fed.R. Crim.P. 35(a) to vacate either one of the two sentences on the ground that Congress did not intend to punish his conduct twice. The court denied his motion. Stafford timely appeals from that final order. We have jurisdiction under 28 U.S.C. § 1291.
ANALYSIS
The legality of the sentence imposed by the district court is a question of law that this court reviews de novo. United States v. Fowler, 794 F.2d 1446, 1449 (9th Cir. 1986), cert. denied, — U.S.-, 107 S.Ct. 1309, 94 L.Ed.2d 153 (1987). The Supreme Court has identified the framework of analysis for determining whether Congress intended separate punishment for multiple offenses arising from a single activity.1 When congressional intent cannot be clearly inferred from the statutory language or *1481legislative history, the Court employs the rule of statutory construction announced in Blockburger v. United States, 284 U.S. 299, 52 S.Ct. 180, 76 L.Ed. 306 (1932). See, e.g., Ball v. United States, 470 U.S. 856, 861-64, 105 S.Ct. 1668, 1671-73, 84 L.Ed.2d 740 (1985); United States v. Woodward, 469 U.S. 105, 105 S.Ct. 611, 83 L.Ed.2d 518 (1985); Albernaz, 450 U.S. at 340-43, 101 S.Ct. at 1142-45. The Blockburger test, however, only establishes a presumption of congressional intent and does not control when Congress’ intent regarding separate punishment can be clearly inferred from the statute’s language or legislative history. Garrett v. United States, 471 U.S. 773, 779, 105 S.Ct. 2407, 2412, 85 L.Ed.2d 764 (1985). In the present case, neither the language of the Travel Act nor its legislative history clearly indicates Congress’ intent regarding separate punishment for violation of the Act and fpr the offense constituting the underlying “unlawful activity.” Therefore, we look to the Blockburger test.
1. THE BLOCKBURGER ANALYSIS
The Blockburger test looks to whether each offense
requires proof of a different element____ [W]here the same act or transaction constitutes a violation of two distinct statutory provisions, the test to be applied to determine whether there are two offenses or only one is whether each provision requires proof of an additional fact which the other does not.
Blockburger, 284 U.S. at 304, 52 S.Ct. at 182. “The assumption underlying the Blockburger rule is that Congress ordinarily does not intend to punish the same offense under two different statutes.” Ball, 470 U.S. at 861, 105 S.Ct. at 1672.2
The first step under Blockburger is to identify the elements of the offenses at issue. The obstruction of a criminal investigation statute provides:
(a) Whoever willfully endeavors by means of bribery to obstruct, delay, or prevent the communication of information relating to a violation of any criminal statute of the United States by any person to a criminal investigator shall be fined not more than $5,000, or imprisoned not more than five years, or both.
18 U.S.C. § 1510(a). The Travel Act provides:
(a) Whoever travels in interstate or foreign commerce or uses any facility in interstate or foreign commerce, including the mail, with intent to—
(1) distribute the proceeds of any unlawful activity; or
(2) commit any crime of violence to further any unlawful activity; or
(3) otherwise promote, manage, establish, carry on, or facilitate the promotion, management, establishment, or carrying on, of any unlawful activity,
and thereafter performs or attempts to perform any of the acts specified in sub-paragraphs (1), (2), and (3), shall be fined not more than $10,000 or imprisoned for not more than five years, or both.
(b) As used in this section “unlawful activity” means ... extortion, bribery, or arson in violation of the laws of the State in which committed or of the United States.
18 U.S.C. § 1952. Thus, the elements of a Travel Act offense are: “(1) interstate commerce or use of an interstate facility (2) with intent to promote an unlawful activity and (3) a subsequent overt act in furtherance of that unlawful activity.” United States v. Tavelman, 650 F.2d 1133, 1138 (9th Cir.1981), cert. denied, 455 U.S. 939, 102 S.Ct. 1429, 71 L.Ed.2d 649 (1982).
*1482Clearly the Travel Act has an interstate travel element that section 1510 does not. Therefore, proof of a section 1510 offense will not necessarily prove a Travel Act offense. Stafford argues, however, that a section 1510 offense would always be proved if a Travel Act conviction could be had for crossing state lines to perform the activity prohibited by section 1510. Thus, Stafford contends, the Travel Act subsumes the predicate section 1510 offense, and punishment for both offenses is improper.
It is no answer to Stafford’s argument that the requisite “unlawful activity” for a Travel Act offense could include activity other than the commission of a section 1510 offense. (The Travel Act defines “unlawful activity” to include, among other things, “extortion, bribery, or arson” in violation of state or federal law. 18 U.S.C. § 1952(b).) The Supreme Court in Whalen v. United States, 445 U.S. 684, 100 S.Ct. 1432, 63 L.Ed.2d 715 (1980), reversed the imposition of consecutive sentences for felony murder and rape where the rape was the requisite felony for invoking the felony murder offense. The Court, applying the Blockburger analysis,3 found the rape to be a necessary element of the felony murder, even though five other enumerated offenses (e.g., kidnapping) could serve as the predicate felony. Id. at 693-95, 100 S.Ct. at 1438-40. The Court held that listing six possible predicate felonies in a single felony murder statute had the same effect as six. separate statutes, each defining felony murder in terms of a different felony. Id. at 694, 100 S.Ct. at 1439. The logic of Whalen applies to the Travel Act, which defines “unlawful activity” to include various federal and state offenses. Therefore, section 1510 and the Travel Act would be separate offenses for purposes of the Blockburger test only if section 1510 required proof of a fact beyond those required to sustain a conviction under the Travel Act for performing or attempting to perform activity unlawful under section 1510. 4
We agree with the Fourth and Sixth Circuits that the Travel Act and its predicate offense will ordinarily constitute separate offenses for purposes of the Blockburger test. See United States v. Teplin, 775 F.2d 1261, 1265 (4th Cir.1985); United States v. Finazzo, 704 F.2d 300, 307-08 (6th Cir.), cert. denied, 463 U.S. 1210, 103 S.Ct. 3543, 77 L.Ed.2d 1392 (1983). The Travel Act does not require the commission of the predicate offense; rather, only an “attempt[ ] to promote” the unlawful activity, 18 U.S.C. § 1952(a), with “a subsequent overt act in furtherance of that unlawful activity.” Tavelman, 650 F.2d at 1138; see also United States v. Jones, 642 F.2d 909, 913 (5th Cir.1981) (subsequent facilitating act required by Travel Act need only make the unlawful activity easier and need not itself be unlawful). Thus, proof of a Travel Act violation will not ordinarily prove a violation of the underlying offense.
Stafford claims, however, that this logic does not automatically apply to section 1510. Stafford argues that any subsequent overt act to further the activity prohibited by section 1510 is itself sufficient to *1483violate section 1510. If section 1510 criminalizes any effort to facilitate the bribery of an informant, including preparations for the bribe (e.g., the arrangement of a meeting with the informant and the securing of the intended bribery money), then we believe section 1510’s “endeavor” and the Travel Act’s “attempt[]” would be synonymous. In that case, violation of the Travel Act for traveling interstate to commit a section 1510 offense would necessarily entail a violation of section 1510, and multiple punishment would be improper under Blockburger.
The unambiguous language of section 1510, however, refutes Stafford’s contention. Section 1510 prohibits “willfully endeavoring] by means of bribery to obstruct, delay, or prevent” communication of information to a criminal investigator. 18 U.S.C. § 1510(a). The statute does not prohibit “endeavors to bribe,” but rather “endeavors to obstruct communication” through the use of bribery. The only defensible interpretation of the statute is that “by means of bribery” restricts the form of the punishable endeavor to obstruct communication.5 On its face, the statute requires actual bribery; we refuse to read attempted bribery or efforts at bribery into the statute where Congress has not included such language.
Judge Pregerson argues in dissent that the legislative history of former section 15106 indicates that the statute does not require an actual bribe. It is an established rule of statutory construction that when the terms of a statute are unambiguous, judicial inquiry is complete except in rare and exceptional circumstances. See United States v. James, — U.S.-, 106 5. Ct. 3116, 3122, 92 L.Ed.2d 483 (1986). Even if it were necessary to resort to legislative history to interpret section 1510, the language of the House report that Judge Pregerson relies upon does not support his reading of the statute. The House report defines endeavor as
any effort or essay to accomplish the evil purpose that this act is designed to present ... Thus, where a person’s acts have not progressed far enough to amount to an attempt, under the act such acts would come within the scope of the word “endeavor” and then be subject to punishment.
H.R.Rep. No. 658, 90th Cong., 1st Sess., reprinted in, 1967 U.S.Code Cong. & Admin.News 1760, 1762. We do not dispute that endeavor should be read broadly and encompass acts that are not sufficient to constitute an attempt. This broad reading of endeavor applies, however, to the “evil purpose” of “obstructpng] the communication of information ... to a criminal investigator.” 18 U.S.C. § 1510(a). The House Report in no way suggests that the statute encompasses “endeavoring to bribe.”
Because section 1510 requires actual bribery, and the Travel Act merely requires an overt act in furtherance of the underlying unlawful activity, proof of a Travel Act offense for performing or attempting to perform a section 1510 offense will not necessarily prove a section 1510 violation. Preparations for the bribe, for example, will suffice as a subsequent facilitating act *1484for purposes of the Travel Act but will not constitute bribery for purposes of section 1510. Under Blockburger, the two offenses are not the same, and Congress is presumed to have intended to permit multiple punishment under them.
II. INTERSTATE TRAVEL ELEMENT
Stafford argues that even if the Travel Act and section 1510 are different offenses under the Blockburger test, they are directed to the same evil — the commission of the underlying unlawful activity — and Congress would not have intended to punish his actions under both statutes.7 Stafford cites United States v. Roselli, 432 F.2d 879 (9th Cir.1970), cert. denied sub nom. Teitelbaum v. United States, 401 U.S. 924, 91 S.Ct. 883, 27 L.Ed.2d 828 (1971). The court in Roselli held that the defendant need not know that he used an interstate facility to violate the Travel Act. 432 F.2d at 890. The court gave two reasons. First, the statutory language does not require knowledge of the interstate element. Id. Second, and of importance to this case, the court found “quite clear that in enacting section 1952 Congress was not concerned with regulating interstate travel or the use of interstate facilities, but rather with directly suppressing unlawful local activities from which organized crime drew its sustenance.” Id. at 891. The court found the interstate component of the Travel Act to be “ ‘merely a ... ground for federal jurisdiction’ ” to reach the undesired underlying activity. Id. (quoting United States v. Blassingame, 427 F.2d 329, 330 (2d Cir.1970), cert. denied, 402 U.S. 945, 91 S.Ct. 1629, 29 L.Ed.2d 114 (1971)).
If Congress merely intended the interstate travel component of the Travel Act to provide a basis for federal jurisdiction, we would have serious doubts about Congress’ intent to punish the defendant both for the underlying offense and for the same conduct under the Travel Act. We do not, however, believe Congress’ intent to be so limited. The Supreme Court, in a decision subsequent to Roselli, found the Travel Act to be “in short, an effort to deny individuals who act for such a criminal purpose access to the channels of commerce.” Erlenbaugh v. United States, 409 U.S. 239, 246, 93 S.Ct. 477, 482, 34 L.Ed.2d 446 (1972). The Court noted Congress’ expressed concern with the inability of state law enforcement agencies to reach criminal activity spanning their borders, id. at 246 & n. 20, 93 S.Ct. at 481 & n. 20 (citing H.R.Rep. No. 966, 87th Cong., 1st Sess. 3, reprinted in, 1961 U.S.Code Cong. & Admin.News 2664, 2665 (states have difficulty reaching non-resident racketeers who control operations within the state)), and effectively disavowed Roselli’s reading of the limited congressional purpose behind the Travel Act. Further, the actual wording of the Travel Act belies the Roselli interpretation of congressional intent. If Congress used the interstate component of the Travel Act merely to obtain a jurisdictional “peg,” it would have been unnecessary to define “unlawful activity” to include various federal offenses because those offenses already provided federal jurisdiction. This court in United States v. Polizzi, 500 F.2d 856 (9th Cir.1974), cert. denied sub nom. Emprise Corp. v. United States, 419 U.S. 1120, 95 S.Ct. 802, 42 L.Ed.2d 820 (1975), also implicitly rejected the idea that the interstate travel component of the Travel Act merely provided a basis for federal jurisdiction. The court found that the plain wording of the Travel Act and the absence of any contrary indication of legislative history permitted separate punishment for each act of travel even though each act related to the same underlying unlawful activity. 500 F.2d at 897-99. If Congress merely intended the Travel Act to criminalize the underlying activity, multiple prosecutions for each act of travel to pro*1485mote the same unlawful activity would make no sense.8
The Pollizi decision recognized the distinct danger posed by each act of travel:
Congress may well have concluded there was a separate social interest in deterring each act of travel in furtherance of an illegal enterprise: each successive trip may increase the success of the illegal activity, and a decision not to make a given trip for fear of additional penal consequences could therefore limit the harm to society § 1952 is intended to prevent.
500 F.2d at 898 n. 7. Congress’ concern that the criminal’s use of interstate facilities decreases the likelihood of detection by law enforcement agencies and increases the likelihood of success of the criminal endeavor, see 1961 U.S.Code Cong. & Admin.News at 2665, likewise could support the conclusion that Congress intended to permit separate punishment because the use of interstate facilities posed a danger distinct from the actual commission of the crime. The Supreme Court has recognized that the increased likelihood of success resulting from the employment of a particular means to a criminal end poses a “distinct danger” from the actual commission of the offense. See Iannelli v. United States, 420 U.S. 770, 778, 95 S.Ct. 1284, 1290, 43 L.Ed.2d 616 (1975) (Congress intended to permit separate punishment for conspiracy and the underlying offense, because, inter alia, conspiracy increased the likelihood of success of the underlying offense). We are, therefore, unable to discern a clear congressional intent not to permit multiple punishment under the Travel Act and the underlying offense.9
CONCLUSION
The Travel Act and 18 U.S.C. § 1510 each require proof of an element that the other does not. Because no clear evidence of contrary congressional intent exists, Congress is presumed to have intended to permit separate punishment for each offense. Stafford’s argument that we should adopt the rule of lenity in the absence of clear congressional intent to punish his activity as separate offenses has already been answered: “if anything is to be assumed from the congressional silence on this point, it is that Congress was aware of the Blockburger rule and legislated with it in mind.” Albernaz, 450 U.S. at 341-42, 101 S.Ct. at 1143-44. The judgment of the district court is AFFIRMED.