delivered the opinion of the .Court.
This case is before us for the second time. The present litigation began with a dispute between the petitioning unions and respondents, co-partners in the business of selling lumber and other materials in California. Respondents' began an action , in the Superior Court for the County of San Diego, asking for an injunction and damages. Upon hearing, the trial court found the following facts. In March of 1953 the unions sought from respondents an agreement to retain in their employ only those workers who were already members of the unions, or who applied for membership within thirty days. Respondents refused, claiming that none of their employees had shown a desire to join a union, and that, in any event, they could not accept such an arrangement until one of the unions had been designated by the employees as a collective bargaining agent., The unions began at once peacefully to picket the respondents’ place of business, and to exert pressure on customers and suppliers in order to persuade them to stop dealing with respondents. The sole purpose of these pressures was to compel execution of the proposed contract. The unions contested this finding, claiming that the only purpose of their activities was to. educate the workers and persuade them to become members. On the basis of . its findings, the court enjoined the unions from picketing and from the use of other pressures to force an agreement, until one of *238them had been properly designated as a collective bargaining agent. The court also awarded $1,000 damages for losses found to have been sustained.
At the time the suit in the state court was started, respondents had begun a representation proceeding before the National Lafcor Relations Board. The Regional Director declined jurisdiction, presumably because the amount of interstate commerce involved did not meet the Board’s monetary standards in taking jurisdiction.
On appeal, the California Supreme Court sustained the judgment of the Superior Court, 45 Cal. 2d 657, 291 P. 2d 1, holding that, since the National Labor Relations Board had declined to exercise its jurisdiction, the California courts had power over the dispute. They further decided that the conduct of thé union constituted an unfair labor practice under § 8 (b) (2) of the National Labor Relations Act, and hence was not privileged under California law. As the California court itself later pointed out this decision did not specify what law, staté or federal, was the basis of the relief granted. Both state and federal law played a part but, “[a]ny distinction as between those laws was not thoroughly explored.” Garmon v. San Diego Bldg. Trades Council, 49 Cal. 2d 595, 602, 320 P. 2d 473, 477.
We granted certiorari, 351 U. S. 923, and decided the case together with Guss v. Utah Labor Relations Board, 353 U. S. 1, and Amalgamated Meat Cutters v. Fairlawn Meats, Inc., 353 U. S. 20. In those cases, we held that the refusal of the National Labor Relations Board to assert jurisdiction did not leave with the States power over activities they otherwise would be pre-empted from regulating. Both Guss and Fairlawn involved relief of an equitable nature. In vacating and remanding the-judgment of the California court in this case, we pointed out that those cases controlled this-one, “in its major aspects.” 353 U. S., at 28. However, since it was not clear whether the *239judgment for damages would be sustained under California law, we remanded to the state court for consideration of that local law issue. The federal question, namely, whether the National Labor Relations Act precluded California from granting an award for damages arising out of the conduct in question, could not be appropriately decided until the antecedent state law question was decided by the state court.
On remand, the California court, in accordance with our decision in Guss, set aside the injunction, but sustained the award of damages. Garmon v. San Diego Bldg. Trades Council, 49 Cal. 2d 595, 320 P. 2d 473 (three judges dissenting). After deciding- that California had jurisdiction to award damages for injuries caused by the union’s activities, the California court held that those activities constituted a tort based on an unfair labor practice under state law. In so holding the court relied on general tort provisions of the California Civil Code, §§ 1677, 1708, as well as state enactments dealing specifically with labor relations, Calif. Labor Code, § 923 (1937); ibid., §§ 1115-1118 (1947).
We again granted certiorari, 357 U. S. 925, . to determine whether the California court had jurisdiction to award damages arising out of peaceful union activity which it could not enjoin.
The issue is a variant of a familiar theme. It began with Allen-Bradley v. Wisconsin Board, 315 U. S. 740, was greatly intensified by litigation flowing from the Taft-Hartley Act, and has recurred here in almost a score of. cases during the last decade. The comprehensive regulation of industrial relations by Congress, novel federal legislation twenty-five years ago but now an integral part of our economic life, inevitably gave rise to difficult problems of federal-state relations. To be sure, in the abstract these problems came to us as ordinary questions of statutory construction. But they involved a more complicated *240and perceptive process than is conveyed'by the delusive phrase, “ascertaining the - intent of the legislature.” Many of these problems probably coíild not have been, at all events were not, foreseen by the Congress. Others were only dimly perceived and their precise scope only vaguely defined. This Court was called upon to apply a new and complicated legislative scheme, the aims and social policy of which were drawn with broad strokes while the details had to be filled in, to no small extent, by the judicial process. Recently we indicated the task that was thus cast upon this Court in carrying out with fidelity the purposes of Congress, but doing so by giving application to congressional incompletion. What we said in Weber v. Anheuser-Busch, Inc., 348 U. S. 468, deserves repetition, because the considerations there outlined guide this day’s decision:
“By the Taft-Hartley Act, Congress did not exhaust the full sweep of legislative power over industrial relations given by the Commerce Clause. Congress formulated a code whereby it outlawed some aspects of labor activities and left others free for the operation of economic forces. As to both categories, the areas that have been pre-empted by federal authority and thereby withdrawn from state power are not susceptible of delimitation by fixed metes and bounds. Obvious conflict, actual or potential, leads to easy judicial exclusion of state action. Such was the situation in Garner v. Teamsters Union, supra. But as the opinion in that case recalled, the Labor Management Relations Act ‘leaves much to the states, though Congress has refrained from telling us how much.’ 346 U. S., at 488. This penumbral area can be rendered progressively clear only by the course of litigation.” 348 U. S., at 480-481. -
*241The case before us concerns one of the most teasing and frequently litigated areas of indhstrial relations, the multitude of activities regulated by §§ 7 and 8 of the National Labor Relations Act. 61 Stat. 140, 29 U. S. C. §§ 157, 158. These broad provisions govern both protected “concerted activities” and unfair labor practices. They regulate the vital, economic instruments of the strike, and the picket line, and impinge on the clash of the still unsettled claims between employers and labor unions. The extent to which the variegated laws of the several States are displaced by a single, uniform, national rule has been a matter of frequent and recurring concern. As we pointed out the other day, “the statutory implications concerning what has been taken fropi the States ¿nd what has been left to them are of a Delphic nature, to be translated into concreteness by the process of litigating elucidation.” International Assn. of Machinists v. Gonzales, 356 U. S. 617, 619.
In the area of regulation with which we are here concerned, the process thus described has contracted initial ambiguity and doubt and established guides for judgment by interested parties and certainly guides for decision. We state these principles in full realization that, in the course of a process of tentative, fragmentary illumination carried on over more than a decade during which the writers of opinions ’ almost^inevitably, because unconsciously, focus their primary attention on the facts of particular situations, language may have been used or views implied which'do not completely harmonize with the clear pattern which the decisions have evolved. But it may safely be claimed that the basis and purport of a long series of adjudications have “translated into concreteness” the consistently applied principles which decide this case.
In determining the extent to which state regulation must yield to subordinating federal authority, we have *242been concerned with delimiting areas of potential conflict; potential conflict of rules of law, of remedy, and of administration. The nature .of the judicial process precludes an ad hoc inquiry into the special problems of labor-management relations involved in a particular set of occurrences in order to ascertain the precise nature and degree of federal-state conflict there involved, and more particularly what exact mischief such a conflict would cause. Nor is. it our business to attempt this. Such determinations inevitably depend upon judgments on the impact of these particular conflicts on the entire scheme of federal labor policy and administration. Our task is confined to dealing with classes of situations. To the National Labor Relations Board and to Congress must be left those precise and closely limited demarcations that can be adequately fashioned only by legislation and administration. We have necessarily been concerned with the potential conflict of two law-enforcing authorities, with the disharmonies inherent in two systems, one federal the other state, of inconsistent standards Qf substantive law and differing remedial schemes. But the unifying consideration of our decisions has been regard to the fact that Congress has entrusted administration of the labor policy for the Nation to a centralized administrative agency, armed with its own procedures, and equipped with its specialized knowledge and cumulative experience:
“Congress did not .merely lay down a substantive rule of law to be enforced by any tribunal competent to apply law generally to the parties.. It went on to confide primary interpretation and application of its rules to a specific and specially constituted tribunal and prescribed a particular procedure for investigation, complaint and notice, and hearing and decision, including judicial relief pending a final administrative order. Congress evidently considered that centralized administration of specially designed pro*243cedures was necessary to obtain uniform application of its substantive rules and to avoid these diversities and conflicts likely to result from a variety of local procedures and attitudes towards labor controversies. ... A multiplicity of tribunals and a diversity of procedures are quite as apt to produce incompatible or conflicting adjudications as are different rules of substantive law. . . Garner v. Teamsters Union, 346 U. S. 486, 490-491.
Administration is more than a means of regulation; administration is regulation. We have been concerned with conflict in its broadest sense; conflict with a complex and interrelated federal scheme of law, remedy, and administration. Thus, judicial concern has necessarily focused on the nature of the activities which the States have sought to regulate, rather than on the method of regulation adopted. When the exercise of state power over a particular area of activity threatened interference with the clearly indicated policy of industrial relations, it has been judicially necessary to preclude the States from acting.1 However, due regard for the presuppositions of our embracing federal system, including the principle of diffusion of power not as a matter of doctrinaire localism but as a promoter of democracy, has required us not to find withdrawal from the States of power to regulate where the activity regulated was a merely peripheral concern of the Labor Management Relations Act. See Interna*244tional Assn. of Machinists v. Gonzales, 356 U. S. 617. Or where the regulated conduct touched interests so deeply rooted in local feeling and responsibility that, in the absence ,of compelling congressional direction, we could not infer that Congress had deprived the States of the power to act.2
When it is clear or may fairly be assumed that the activities which a State purports to regulate are protected by § 7 of the National Labor Relations Act, or constitute an unfair labor practice under § 8, due regard for the federal enactment requires that state jurisdiction must yield. To leave the States free to regulate conduct so plainly within the central aim of federal regulation involves too great a danger of conflict between power asserted by Congress and requirements imposed by state law. Nor has it mattered, whether the States have acted through laws of broad general application rather than laws specifically directed towards the governance of industrial relations.3 Regardless of the mode adopted, to allow the States to control conduct which is the subject of national regulation would create potential frustration of national purposes.
At times it has not been clear whether the particular activity regulated by the States was governed by § 7 or § 8 Or was, perhaps, outside both these sections. But courts are not primary tribunals to adjudicate such issues. It is essential to the administration of the Act that these determinations be left in the first instance to the National *245Labor Relations Board. What is outside the scope of this Court’s authority cannot remain within a State’s power and state jurisdiction too must yield to the exclusive primary competence of the Board. See, e. g., Garner v. Teamsters Union, 346 U. S. 485, especially at 489-491; Weber v. Anheuser-Busch, Inc., 348 U. S. 468.
The case before us is such a case. The adjudication in California has throughout been based on the assumption that the behavior of the petitioning unions constituted an unfair labor practice. This conclusion was derived by the California courts from the facts as well as from their view of the Act. It is not for us to decide whether the National Labor Relations Board would have, or should have, decided these questions in the same manner. When an activity is arguably subject to § 7 or § 8 of the Act, the States as well as the federal courts must defer to the exclusive competence of the National Labor Relations Board if the danger of state interference with national policy is to be averted.
To require the States to yield to the primary jurisdiction of the National Board does not ensure Board adjudication of the status of a disputed activity. If the Board decides, subject to appropriate federal judicial review, that conduct is protected by § 7, or prohibited by § 8, then the matter is at an end, and the States are ousted of all jurisdiction. Or, the Board may decide that an activity is neither protected nor prohibited, and thereby raise the question whether such activity may be regulated by the States.4 However, the Board may also fail to determine the status of the disputed conduct by declining to assert jurisdiction, or by refusal of the General Counsel to file *246a charge; or by adopting some other disposition which does not define the nature of the activity with unclouded legal significance. This was the basic problem underlying our decision in Guss v. Utah Labor Relations Board, 353 U. S. 1. In that case we held that the failure of the National Labor Relations Board to assume jurisdiction did not leave the States free to regulate activities they would otherwise be precluded from regulating. It follows that the failure of the Board to define the legal Significance under the Act of a particular activity does not give the States the power to act. ’In the absence of the Board’s clear determination that an activity is neither protected nor prohibited or of compelling precedent applied to essentially undisputed facts, it is not for this Court to decide whether such activities are subject to state jurisdiction. The withdrawal of this narrow area from possible state activity follows from our decisions in Weber and Guss. The governing consideration is that to allow the States to control activities that are potentially subject to federal regulation involves too great a danger of conflict with national labor policy.5
In the light of these principles the case before us is clear. Since the National Labor Relations Board has not adjudicated the status of the conduct for which the State of California seeks to give a remedy in damages, and since such activity is arguably within the compass of § 7 or § 8 of the Act, the State’s jurisdiction is displaced.
Nor is it significant that California asserted its power to givfe damages rather than to enjoin what the Board may restrain though it could not compensate. Our concern is with delimiting areas of conduct which must be free from state regulation if national policy is to be left unhampered. *247Such regulation can be as effectively exerted through an award of damages as through some form of preventive relief. The obligation to pay compensation can be, indeed is designed to be, a potent method of governing conduct and controlling policy. Even the States’ salutary effort to redress private wrongs or grant compensation for past harm cannot be exerted to regulate activities that are potentially subject to the exclusivé federal regulatory scheme. See Garner v. Teamsters Union, 346 U. S. 485, 492-497. It may be that an award of damages in a particular situation will not, in fact, conflict with the active assertion of federal authority. The same may be true of the incidence of a particular state injunction. To sanction either involves a conflict with federal policy in that it involves allowing two law-making sources to govern. In fact, since remedies form an ingredient of any integrated scheme of regulation, to allow the State to grant a remedy here which has been withheld from the National Labor Relations Board only accentuates the danger of conflict.
It is true that we have allowed the States to grant compensation for the consequences, as defined by the traditional law of torts, of conduct marked by violence and imminent threats to the public order. United Automobile Workers v. Russell, 356 U. S. 634; United Construction Workers v. Laburnum Corp., 347 U. S. 656. We have also allowed the States to enjoin such conduct. Youngdahl v. Rainfair, 355 U. S. 131; Auto Workers v. Wisconsin Board, 351 U. S. 266. State jurisdiction has prevailed in these situations because the compelling state interest, in the scheme of our federalism, in the maintenance of domestic peace is not overridden in the absence of clearly expressed congressional direction. We recognize that the opinion in United Construction Workers v. Laburnum Corp., 347 U. S. 656, found support in the fact that the state remedy had no federal counterpart. But that deci*248sion was determined, as is demonstrated by the question to which review was restricted, by the “type of conduct” involved, i. e., “intimidation and threats of violence.” 6 In the present case there is no such compelling state interest.
The judgment below is
Reversed.