Mb. Justice Stone
delivered the opinion of the Court.
Petitioner, a Pennsylvania corporation, is engaged in the manufacture, at its factory in Philadelphia, of hosiery, a substantial part of which is shipped in interstate commerce. It brought the present suit in the federal district court for Eastern Pennsylvania against respondent Federation, a labor organization, and its officers, to recover treble the amount of damage inflicted on it by respondents in conducting a strike at petitioner’s factory alleged [481]*481to be a conspiracy in violation of the Sherman AntiTrust Act. 26 Stat. 209, 15 U. S. C. § 1. The trial to a jury resulted in a verdict for petitioner in the sum of $237,310, respondents saving by proper motions and exceptions the question whether the evidence was sufficient to establish a violation of the Sherman Act. The trial judge trebled the verdict to $711,932.55, in conformity to the provision of the Sherman Act as amended by § 4 of the Clayton Act, 1914, 38 Stat. 731,15II. S. C. § 15, and gave judgment accordingly. The Court of Appeals for the Third Circuit reversed, 108 F. 2d 71, on the ground that the interstate commerce restrained or affected by respondents’ acts was unsubstantial, the total shipment of merchandise from petitioner’s factory being less than three per cent, of the total value of the output in the entire industry of the country, and on the further ground that the evidence failed to show an intent on the part of respondents to restrain interstate commerce. We granted certiorari, 309 U. S. 644, the questions presented being of importance in the administration of the Sherman Act.
The facts are undisputed. There was evidence from which the jury could have found as follows. Petitioner employs at its Philadelphia factory about twenty-five hundred persons in the manufacture of hosiery, and manufactures annually merchandise of the value of about $5,000,000. Its principal raw materials are silk and cotton, which are shipped to it from points outside the state. It. ships interstate more than 80 per cent, of its finished product, and in the last eight months of 1937 it shipped in all 274,791 dozen pairs of stockings. In April, 1937, petitioner was operating a non-union shop. A demand of the respondent Federation at that time for a closed shop agreement came to nothing. On May 4, 1937, when only eight of petitioner’s employees were members of the Federation, it ordered a strike. Shortly after midday on [482]*482May 6, 1937, when petitioner’s factory was shut down, members of the union, employed by other factories in Philadelphia who had stopped work, gathered at petitioner’s plant. Respondent Leader, president of the Federation, then made a further demand for a closed shop agreement. When this was refused Leader declared a “sit down strike.” Immediately, acts of violence against petitioner’s plant and the employees in charge of it were committed by the assembled mob. It forcibly seized the plant, whereupon, under union leadership, its members were organized to maintain themselves as sit-down strikers in possession of the plant, and it remained in possession until June 23, 1937, when the strikers were forcibly ejected pursuant to an injunction ordered by the Court of Appeals for the Third Circuit in Apex Hosiery Co. v. Leader, 90 F. 2d 155, 159; reversed and dismissal ordered as moot in Leader v. Apex Hosiery Co., 302 U. S. 656.
The locks on all gates and entrances of petitioner’s plant were changed; only strikers were given keys. No others were allowed to leave or enter the plant without permission of the strikers. During the period of their occupancy, the union supplied them with food, blankets, cots, medical care, and paid them strike benefits. While occupying the factory, the strikers wilfully wrecked machinery of great value, and did extensive damage to other property and equipment of the company. All manufacturing operations by petitioner ceased on May 6th. As the result of the destruction of the company’s machinery- and plant, it did not resume even partial manufacturing operations until August 19, 1937. The record discloses a lawless invasion of petitioner’s plant and destruction of its property by force and violence of the most brutal and wanton character, under leadership and direction of respondents, and without interference by the local authorities.
For more than three months, by reason of respondents’ acts, manufacture was suspended at petitioner’s plant [483]*483and the flow of petitioner’s product into interstate commerce was stopped. When the plant was seized, there were on hand 130,000 dozen pairs of finished hosiery, of a value of about $800,000, ready for shipment on unfilled orders, 80 per cent, of which were to be shipped to points outside the state. Shipment was prevented by the occupation of the factory by the strikers. Three times in the course of the strike respondents refused requests made by petitioner to be allowed to remove the merchandise for the purpose of shipment in filling the orders.
Section 1 of the Sherman Act provides: “Every contract, combination in the form of trust or otherwise, or conspiracy, in restraint of trade or commerce among the several States, or with foreign nations, is hereby declared to be illegal.” Only a single question is presented by the record for our decision, whether the evidence which we have detailed, whose verity must be taken to be established by the jury’s verdict, establishes a restraint of trade or commerce which the Sherman Act condemns.
It is not denied, and we assume for present purposes, that respondents by substituting the primitive method of trial by combat,1 for the ordinary processes of justice and more civilized means of deciding an industrial dispute, violated the civil and penal laws of Pennsylvania which authorize the recovery of full compensation and impose criminal penalties for the wrongs done. But in this suit, in which no diversity of citizenship of the parties is alleged or shown, the federal courts are without authority to enforce state laws. Their only jurisdiction is to vindicate such federal right as Congress has conferred on petitioner by -the Sherman Act and violence, [484]*484as will appear hereafter, however reprehensible, does not give the federal courts jurisdiction.
At the outset, and before considering the more substantial issues which we regard as decisive of this cause, it is desirable to remove from the field of controversy certain questions which have been much argued here and below, but which we think, in the circumstances of the present case, are irrelevant to decision. We find abundant support for petitioner’s contention that the effect of the sit-down strike was to restrict substantially the interstate transportation of its manufactured product, so as to bring the acts of respondents by which the restriction was effected within the reach of the commerce power if Congress has seen fit to exercise it. Cessation of petitioner’s manufacturing operations, which respondents compelled, indubitably meant the cessation of shipment interstate. The effect upon the commerce resulted naturally and inevitably from the cause. The occupancy of petitioner’s factory by the strikers prevented the shipment of the substantial amount of merchandise on hand when-the strike was called. In point of the immediacy of the effect of - the strikers’ acts upon the interstate transportation involved and of its volume, the case does not differ from many others in which we have sustained the Congressional exercise of the commerce power. The national power to regulate commerce is not restricted to that which is nationwide in its scope. Here the strikers’ activities were as closely related to interstate commerce arid affected it as substantially as numerous other activities not in themselves interstate commerce which have nevertheless been held to be subject to federal statutes enacted in the exercise of the commerce power;2 More recently, [485]*485where the statute was by its terms applicable and the question was of Congressional power, we have sustained the application of the Wagner Act, 49 Stat. 449, 29 U. S. C. §§ 151-166, regulating labor relations “affecting” interstate commerce to situations no more closely related to the commerce than these, and where the interstate commerce affected was no greater in volume.3 And in the application of the Sherman Act, as we have recently had occasion to point out, it is the nature of the restraint and its effect on interstate commerce and not the amount of the commerce which are the tests of violation. See United States v. Socony-Vacuum Oil Co., ante, p. 224, note 59. Cf. Labor Board v. Fainblatt, 306 U. S. 601, 606.
We think also, as petitioner contends, that the jury’s verdict must be taken as a finding supported by evidence that respondents intended to prevent petitioner’s shipments hr interstate commerce in the sense that respondents must be taken to have intended the natural and probable consequences of their acts. The trial court left it to the jury to say whether the respondents intended to restrain petitioner’s interstate shipments, and charged that in a suit to recover damages for violation of the Sherman Act it was necessary for it to find an intent on the part of respondents to cause the prohibited restraint of commerce,4 but that such intent might be inferred [486]*486from their acts in stopping petitioner’s manufacture of a product largely and regularly shipped in interstate commerce. Concededly the purpose of the strikers and their principal objective were to compel petitioner to yield to their demands for a union shop, but it is a matter of common knowledge and experience that the stoppage of a large manufacturing plant, which the strikers did intend, whose product is distributed generally to consumers throughout the country, would prevent its shipments in interstate commerce. We must take it from the jury’s verdict that this was known to the strikers as well as to others. In addition there was specific testimony that the strikers refused to permit the withdrawal of the finished merchandise from petitioner’s factory for shipment.
But the Sherman Act admittedly does not condemn all combinations, and conspiracies which interrupt interstate transportation. United Mine Workers v. Coronado Coal Co., 259 U. S. 344 (First Coronado case); United Leather Workers v. Herkert Co. 265 U. S. 457 (Leather Workers case). In In re Debs, 158 U. S. 564, 600, this Court declined to consider whether the stoppage of trains on an interstate railroad resulting from a strike, was a violation of the Sherman Act — a question which it has not since been called on to- decide.5 It is not seriously [487]*487contended here that a conspiracy to derail and rob an interstate train, even though it were laden with 100,000 dozen pairs of stockings, necessarily would involve a violation of the Sherman Act. This Court has never applied the Act to laborers or to others as a m'eans of policing interstate transportation, and so the question to which we must address ourselves is whether a conspiracy of strikers in a labor dispute to stop the operation of the employer’s factory in order to enforce their demands against the employer is the kind of restraint of trade or commerce at which the Act is aimed, even though a natural and probable consequence of their acts and the only effect on trade or commerce was to prevent substantial shipments interstate by the employer.
A point strongly urged in behalf of respondents in brief and argument before us is that Congress intended to exclude labor organizations and their activities wholly from the operation of the Sherman Act. To this the short answer must be made that for the thirty-two years which have elapsed since the decision of Loewe v. Lawlor, 208 U. S. 274, this Court, in its efforts to determine the true meaning and application of the Sherman Act has repeatedly held that the words of the act, “Every contract, combination ... or conspiracy in restraint of trade or commerce” do embrace to some extent and in some circumstances labor unions and their activities;6 and that during that period Congress, although often asked to do so, has passed no act purporting to exclude labor unions [488]*488wholly from the operation of the Act.7 On the contrary Congress has repeatedly enacted laws restricting or purporting to curtail the application of the Act to labor organizations and their activities, thus recognizing that to some extent not defined they remain subject to it.8 ,
Whether labor organizations and their activities are wholly excluded from the Sherman Act is a question of statutory construction, not constitutional power.9 The long time failure of Congress to alter the Act after it had been judicially construed, and the enactment by Congress of legislation which implicitly recognizes the judicial construction as effective, is persuasive of legislative recognition that the judicial construction is the correct one. This is the more so where, as here, the application of the statute [489]*489to labor unions has brought forth sharply conflicting views both on the Court and in Congress, and where after the matter has been fully brought to the attention of the public and the Congress, the latter has not seen fit to change the statute.
While we must regard the question whether labor unions are to some extent and in some circumstances subject to the Act as settled in the affirmative, it is equally plain that this Court has never thought the Act to apply to all labor union activities affecting interstate commerce. The prohibitions of the Sherman Act were not stated in terms of precision or of crystal clarity and the Act itself did not define them. In consequence of the vagueness of its language, perhaps not uncalculated,10 the courts have been left to give content to the statute, and in the performance of that function it is appropriate that courts should interpret its word in the light of its legislative history and of the particular evils at which the legislation was aimed. Cf. Standard Oil Co. v. United States, 221 U. S. 1; Nash v. United States, 229 U. S. 373; Appalachian Coals v. United States, 288 U. S. 344, 359, 360.
[490]*490The critical words which circumscribe the judicial performance of this function so far as the present case is concerned are “Every . . . combination ... or conspiracy in restraint of trade or commerce.” Since in the present case, as we have seen, the natural and predictable consequence of the strike was the restraint of interstate transportation the precise question which we are called upon to decide is whether that restraint resulting from the strike maintained to enforce union demands by compelling a shutdown of petitioner's factory is the kind of “restraint of trade or commerce” which the Act condemns.
In considering whether union activities like the present may fairly be deemed to be embraced within this phrase, three circumstances relating to the history and application of the Act which are of striking significance must first be taken into account. The legislative history of the Sherman Act as well as the decisions of this Court interpreting it, show that it was not aimed at policing interstate transportation or movement of goods and property. The legislative history and the voluminous literature which was generated in the course of the enactment and during fifty years of litigation of the Sherman Act give no hint that such was its purpose.11 They do not suggest [491]*491that, in general, state laws or law enforcement machinery were inadequate to prevent local obstructions or interferences with interstate transportation, or presented any problem requiring the interposition of federal authority.12 In 1890 when the Sherman Act was adopted there were only a few federal statutes imposing penalties for obstructing or misusing interstate transportation.13 With an expanding commerce, many others have since been enacted safeguarding transportation in interstate commerce as the need was seen, including statutes declaring conspiracies to interfere or actual interference with interstate commerce by violence or threats of violence to be felonies.14 It was another and quite a different evil at [492]*492which the Sherman Act was aimed. It was enacted in the era of “trusts” and of “combinations” of businesses [493]*493and of capital organized and directed to control of the market by suppression of competition in the marketing of goods and services, the monopolistic tendency of which had become a matter of public concern. The end sought was the prevention of restraints to free competition in business and commercial transactions which tended to restrict production, raise prices or otherwise control the market to the detriment of purchasers or consumers of goods and services, all of which had come to be regarded as a special form of public injury.15
[494]*494For that reason the phrase “restraint of trade” which, as will presently appear, had a well-understood meaning at [495]*495common law, was made the means of defining the activities prohibited. The addition of the words “or commerce among the several states” was not an additional kind of restraint to be prohibited by the Sherman Act but was the means used to relate the prohibited restraint of trade to interstate commerce for constitutional purposes, Atlantic Cleaners & Dyers v. United States, 286 U. S. 427, 434, so that Congress, through its commerce power, might suppress and penalize restraints on the competitive system which involved or affected interstate commerce. Because many forms of restraint upon commercial competition extended across state lines so as to make regulation by state action difficult or impossible, Congress enacted the Sherman Act, 21 Cong. Rec. 2456. It was in this sense of preventing restraints on commercial competition that Congress exercised “all the power it possessed.” Atlantic Cleaners & Dyers v. United States, supra, 435.
A second significant circumstance is that this Court has never applied the Sherman Act in any case, whether or not involving labor organizations or activities, unless the Court was of opinion that there was some form of restraint upon commercial competition in the marketing of goods or services16 and finally this Court has refused [496]*496to? apply the Sherman Act in cases like the present in which local strikes conducted by illegal means in a [497]*497production industry prevented interstate shipment of substantial amounts of the. product but in which it was not shown that the restrictions on shipments had operated to restrain commercial competition in some substantial way. First Coronado case, supra; Leather Workers case, supra. Levering & Garrigues Co. v. Morrin, 289 U. S. 103.
The common law doctrines relating to contracts and combinations in restraint of trade were well understood long before the enactment of the Sherman law.17 They were contracts for the restriction or suppression of competition in the market, agreements to fix prices, divide marketing territories, apportion customers, restrict production and the like practices, which tend to raise prices or otherwise take from buyers or consumers the advantages which accrue to them from free competition in the market. Such contracts were deemed illegal and were unenforcible at common law. But the resulting restraints of trade were not penalized and gave rise to no actionable wrong. Certain classes of restraints were not outlawed when deemed reasonable, usually because they served to preserve or protect- legitimate interests, previously existing, of one or more parties to the contract.18
In seeking more effective protection of the public from the growing evils of restraints on the competitive system [498]*498effected by the concentrated commercial power of “trusts” and “combinations” at the close of the nineteenth century, the legislators found ready at their hand the common law concept of illegal restraints of trade or commerce. In enacting the Sherman law they took over that concept by condemning such restraints wherever they occur in or affect commerce between the states. They extended the condemnation of the statute to restraints effected by any combination in the form of trust or otherwise, or conspiracy, as well as by contract or agreement, having those effects on the competitive system and on purchasers and consumers of goods or services which were characteristic of restraints deemed illegal at common law, and they gave both private and public remedies for the injuries flowing from such restraints.
That such is the scope and effect of the Sherman Act was first judicially recognized and expounded in the classic opinion in United States v. Addyston Pipe & Steel Co., 85 F. 271, affirmed 175 U. S. 211, written by Judge, later Chief Justice, Taft, and concurred in by Justice Harlan and Judge, later Justice, Lurton, of this Court. This Court has since repeatedly recognized that the restraints at which the Sherman law is aimed, and which are described by its terms, are only those which are comparable to restraints deemed illegal at common law, although accomplished by means other than contract and which, for constitutional reasons, are confined to transactions in or which affect interstate commerce.19
[499]*499In Standard Oil Co. v. United States, 221 U. S. 1, 54, 55, 58, decided in 1911, this Court, speaking through Chief Justice White, pointed out that the restraint of trade contemplated by § 1 of the Act took its origin from the common law, and that the Sherman Act was adapted to the prevention, in modern conditions, of conduct or dealing effecting the wrong, at which the common law doctrine was aimed. This, it was said, is “the dread of enhancement of prices and of other wrongs which it was thought would flow from the undue limitation on competitive conditions caused by contracts or other acts of individuals or corporations, . . 20 The Court declared, page 59, that “the statute was drawn in the light of the existing practical conception of the law of restraint of trade,” and drew the conclusion that the restraints which were condemned by the statute are those which, following the common law analogy, are “unreasonable or undue.” This view was followed and more explicitly stated in United States v. American Tobacco Co., 221 U. S. 106, [500]*500179, where it was said: “. . . it was held in the Standard Oil case that as the words ‘restraint of trade’ at common law and in the law of this country at the time of the adoption of the Anti-trust Act only embraced acts or contracts or agreements or combinations which operated to the prejudice of the public interests by unduly restricting competition or unduly obstructing the due course of trade or which, either because of their inherent nature or effect or because of the evident purpose of the acts, tete., injuriously restrained trade, that the words as used in the statute were designed to have and did have but a like significance.” In thus grounding the “rule of reason” upon the analogy of the common law doctrines applicable to illegal restraints of trade the Court gave a content and meaning to the statute in harmony with its history and plainly indicated by its legislative purpose. Labor cases apart, which will presently be discussed, this Court has not departed from the conception of the Shterman Act as affording a remedy, public and private, for the public wrongs which flow from restraints of trade in the common law sense of restriction or suppression of commercial competition. In the cases considered by this Court since the Standard Oil case in 1911 some form of restraint of commercial competition has been the sine qua non to the condemnation of contracts, combinations or conspiracies under the Sherman Act, and in general restraints upon competition have been condemned only when their purpose or effect was to raise or fix the market price.21 It is in this sense that it is said that the restraints, actual or intended, prohibited by the Sherman Act are only those which are so substantial as to affect market prices. Restraints on competition or on the course of trade in the merchandising of articles moving in interstate com[501]*501merce is not enough, unless the restraint is shown to have or is intended to have an effect upon prices in the market or otherwise to deprive purchasers or consumers of the advantages which they derive from free competition. Chicago Board of Trade v. United States, 246 U. S. 231, 238; United States v. United States Steel Co., 251 U. S. 417; Cement Manufacturers Assn. v. United States, 268 U. S. 588; United States v. International Harvester Co., 274 U. S. 693; Appalachian Coals v. United States, 288 U. S. 344, 375, et seq.22
The question remains whether the effect of the combination or conspiracy among respondents was a restraint of trade within the meaning of the Sherman Act. This is not a case of a labor organization being used by combinations of those engaged in an industry as the means or instrument for suppressing competition or fixing prices. See United States v. Brims, 272 U. S. 549; Local 167 v. United States, 291 U. S. 293. Here it is plain that the combination or conspiracy did not have as its purpose restraint upon competition in the market for petitioner’s product. Its object was to compel petitioner to accede to' the union demands and an effect of it, in consequence of the strikers’ tortious acts, was the prevention of the removal of petitioner’s product for interstate shipment. So far as appears the delay of these shipments was not intended to have and had no effect on prices of hosiery in the market, and so was in that respect no more a restraint forbidden by the Sherman Act than the restriction upon competition and the course of trade held lawful in Appalachian Coals v. United States, supra, because notwithstanding its effect upon the marketing of the coal [502]*502it nevertheless was not intended to and did not affect market price.
A combination of employees necessarily restrains competition among themselves in the sale of their services to the employer; yet such a combination was not considered an illegal restraint of trade at common law when the Sherman Act was adopted, either because it was not thought to be unreasonable or because it was not deemed a “restraint of trade.” 23 Since the enactment of the [503]*503declaration in § 6 of the Clayton Act that “the labor of a human being is not a commodity or. article of commerce . . . nor shall such [labor] organizations, or the members thereof, be held or construed to be illegal combinations or conspiracies in the restraint of trade under the antitrust laws,” it would seem plain that restraints on the sale of the employee’s services to the employer, however much they curtail the competition among employees, are not in themselves combinations or conspiracies in restraint of trade or commerce under the Sherman Act.
Strikes or agreements not to work, entered into by laborers to compel employers to yield to their demands, may restrict to some extent the power of employers who are parties to the dispute to compete in the market with those not subject to such demands. But under the doctrine applied to non-labor cases, the mere fact of such restrictions on competition does not in itself bring the parties to the agreement within the condemnation of the Sherman Act. Appalachian Coals v. United States, supra, 360. Furthermore, successful union activity, as for example consummation of a wage agreement with employers, may have some influence on price competition by eliminating that part of such competition which is based on differences in labor standards. Since, in order to render a labor combination effective it must eliminate the competition from non-union made goods, see American Steel Foundries v. Tri-City Central Trades Council, 257 U. S. 184, 209, an elimination of price competition based on differences in labor standards is the objective of any national labor organization. But this effect on competition has not been [504]*504considered to be the kind of curtailment of price competition prohibited by the Sherman Act. See Levering & Garrigues Co. v. Morrin, supra; cf. American Foundries case, supra, 209; National Association of Window Glass Mfrs. v. United States, 263 U. S. 403.24 And in any case, the restraint here is, as we have seen, of a different kind and has not been shown to have any actual or intended effect on price or price competition.
[505]*505This Court first applied the Sherman Act to a labor organization in Loewe v. Lawlor, 208 U. S. 274, in 1908, holding that the trial court had erroneously sustained a demurrer to the declaration in a suit for damages for violation of the Sherman Act on the ground that the combination alleged was not within the Act. The combination or conspiracy charged was that of a nation-wide labor organization to force all manufacturers of fur hats in the United States to organize their workers by maintaining a boycott against the purchase of the product of non-union manufacturers shipped in interstate commerce. The restraint alleged was not a strike or refusal to work in the complainants’ plant, but a secondary boycott by which, through threats to the manufacturer’s wholesale customers and their customers, the Union sought to compel or induce them not to deal in the product of the complainants, and to purchase the competing products of other unionized manufacturers. This Court pointed out that the restraint was precisely like that in Eastern States Retail Lumber Dealers Co. v. United States, 234 U. S. 600, 610, 614, in which a conspiracy to circulate a “black list,” intended to persuade retailers not to deal with specified wholesalers, was held to violate the Act because of its restraint upon competition with unlisted wholesalers. The Court in the Loewe case held that the boycott operated as a restraint of trade or commerce within the meaning of the Sherman Act, and that the language of the Act, “every combination, etc.” was broad enough to include a labor union imposing such a restraint. Like problems found a like solution in Duplex Printing Press Co. v. Deering, 254 U. S. 443, and in Bedford Cut Stone Co. v. Journeymen Stone Cutters Assn., 274 U. S. 37; where, in the one case, a secondary boycott, and in the other, the refusal of the union to work on a product in the hands of the purchaser, were carried on on a countrywide scale by a national labor organization, in order to [506]*506induce the purchasers of a manufactured product shipped in interstate commerce to withdraw their patronage from the producer. In both, as in the Loewe case, the effort of the union was to compel unionization of an employer’s factory, not by a strike in his factory but by restraining, by the boycott or refusal to work on the manufactured product, purchases of his product in interstate commerce in competition with the like product of union shops.
In the Bedford Stone case it was pointed out that, as in the Duplex Printing Press Co. case, the strike was directed against the use of the manufactured product by consumers "with the immediate purpose and effect of restraining future sales and shipments in interstate commerce” and “with the plain design of suppressing or narrowing the interstate market,” and that in this respect the case differed from those in which a factory strike, directed at the prevention, of production with consequent-cessation of interstate shipments, had been held not to be a violation of the Sherman law. See First Coronado case, supra; Leather Workers case, supra; cf. Second Coronado case, supra, 310.
It will be observed that in each of these cases where the Act was held applicable to labor unions, the activities affecting interstate commerce were directed at control of the market and were so widespread as substantially to affect it. There was thus a suppression of competition in the market by methods which were deemed analogous to those found to be violations in the non-labor cases. See Montague & Co. v. Lowry, 193 U. S. 38, 45, 46; Retail Lumber Dealers Co. v. United States, supra; Paramount Famous Lasky Co. v. United States, 282 U. S. 30; United States v. First National Pictures, 282 U. S. 44. That the objective of the restraint in the boycott cases was the strengthening of the bargaining position of the union and not the elimination of business competition — which was the end in the non-labor cases — was [507]*507thought to be immaterial because the Court viewed the restraint itself, in contrast to the interference with shipments caused by a local factory strike, to be of a kind regarded as offensive at common law because of its effect in curtailing a free market and it was held to offend against the Sherman Act because it effected and was aimed at suppression of competition with union made goods in the interstate market.
Both the Duplex Printing Co. and Bedford Stone cases followed the enactment of the Clayton Act and the recognition of the “rule of reason” in the Standard Oil case, supra. The applicability of that rule to restraints upon commerce affected by a labor union in order to promote and consolidate the interests of its union was not considered.25 But an important point considered and decided by the Court in both cases was that nothing in the Clayton Act precluded the relief granted. We are not now concerned with the merits of either point.26 The only [508]*508significance of the two cases for present purposes is that in each the Court considered it necessary, in order to support its decision, to find that the restraint operated to suppress competition in the market.
This Court was first called on to consider a case like the present in the First Coronado case, supra. There a local branch of a national labor union sought to unionize a coal mine which was shipping its product interstate to the extent of more than 5,000 tons a- week. Members of the union compelled the mine to shut down, by force and violence, including murder and arson. By reason of their forcible action all work at the mine was prevented, it filled with water, shipments of coal which were regularly moving in interstate commerce as min'ed, ceased, and [509]*509the strikers burned more than ten cars, three of them loaded with coal and .some billed for movement interstate. This Court, notwithstanding the admittedly substantial effect of the strike on the interstate movement of the coal, and the admittedly illegal and outrageous acts of the strikers, held that it was not a restraint of trade or commerce prohibited by the Sherman Act. It rested its decision specifically on two grounds: that “obstruction to coal mining is not a direct obstruction to interstate commerce in coal,” 27 and that the intent to obstruct the mining of coal and to burn the loaded cars, did not necessarily imply an intent to restrain the commerce, although con-cededly interstate shipments and the filling of interstate orders for coal were necessarily ended by the stoppage of mining operations and the destruction of the loaded cars. It perhaps suffices for present purposes to say that if the strike in the Coronado case was not within the Sherman Act because its effect upon the commerce was “indirect” and because the “intention” to shut down the mine and destroy the cars of coal destined for an interstate shipment, did not imply an “intention to obstruct ipterstate commerce,” then the like tests require the like decision here.
But we are not relegated to so mechanical an application of these cryptic phrases in the application of the Sherman Anti-Trust Act, for the Court has since so in[510]*510terpreted them as to give to the phrase “restraint of trade or commerce” a meaning and content consonant with the legislative and judicial history of the Act to which we have referred. In the Leather Workers case, supra, the Court was again called on to determine whether a local strike in a factory which prevented shipment of its product in filling interstate orders of substantial volume violated the Sherman Act. As in the First Coronado case the Court held that the restraint was not one prohibited by the Sherman Act. It pointed out, page 469, that there has been no attempt, as in Loewe v. Lawlor, to boycott the sale of complainant’s products in other states, and that if the interruption of interstate shipments resulting from a local factory strike aimed at compelling the employer to yield to union demands were deemed within the sweep of the Sherman Act, “The natural, logical and inevitable result will be that every strike in any industry or even in any single factory will be within the Sherman Act and subject to federal jurisdiction provided any appreciable amount of its product enters into interstate commerce,” page 471. After discussing the cases which had given currency to the notion that the Sherman Act, where the. combination or conspiracy is not formed with the “intent to restrain trade or commerce,” is to be applied only to those restraints characterized as “direct,” the Court said, page 471:
“This review of the cases makes it clear that the mere reduction in the supply of an article to be shipped in interstate commerce, by the illegal or tortious prevention of its manufacture, is ordinarily an indirect and remote obstruction to that commerce. It is only when the intent or necessary effect upon such commerce in the article is to enable those preventing the manufacture to monopolize the supply, control its price or discriminate as between its would-be purchasers, that the unlawful interference [511]*511with its manufacture can be said directly to burden interstate commerce.”
And the Court added,
“The record is entirely without evidence or circumstances to show that the defendants in their conspiracy to deprive the complainants of their workers were thus directing their scheme against interstate commerce.”
It was thus made apparent that in saying that “indirect obstructions” to commerce were not condemned by the Sherman Act where the conspiracy is not directed at that commerce, the Court was not seeking to apply a purely mechanical test of liability, but was using a shorthand expression to signify that the Sherman Act was directed only at those restraints whose evil consequences are derived from the suppression of competition in the interstate market, so as “to monopolize the supply, control its price or discriminate between its would-be purchasers.” And in speaking of intent as a prerequisite to liability under the Act where the restraint to interstate commerce is “indirect” it meant no more than that the conspiracy or combination must be aimed or directed at the kind of restraint which the Act prohibits or that such restraint is the natural and probable consequences of the conspiracy.
This was again pointed out in the Second Coronado case, supra, 310, where upon a retrial of the case on amended pleadings it appeared that “the purpose of the destruction of the mines was to stop the production of non-union coal and prevent its shipment to markets of other states than Arkansas, where it would by competition tend to reduce the price of the commodity and affect injuriously the maintenance of wages for union labor in competing mines, . . .” The Court declared such a restraint to be a “direct violation of the Sherman Act.” The like distinction was taken and explanation made in the Bedford Stone [512]*512case, supra, pp. 46, 49, where the restraint consisted in the refusal of the unions to work on stone shipped interstate from an open shop quarry after its interstate journey to the purchaser had ended, and where it appeared that the purpose of the strike was to prevent the interstate sale of the stone in competition with the product of unionized producers. Cf. Levering & Garrigues Co. v. Morrin, supra.
These cases show that activities of labor organizations not immunized by the Clayton Act are not necessarily violations of the Sherman Act. Underlying and implicit in all of them is recognition that the Sherman Act was not enacted to police interstate transportation, or to afford a remedy for wrongs, which are actionable under state law, and result from combinations and conspiracies which fall short, both in their purpose and effect, of any form of market control of a commodity, such as to “monopolize the supply, control its price, or discriminate between its would-be purchasers.” These elements of restraint of trade, found to be present in the Second Coronado case and alone to distinguish it from the First Coronado case and the Leather Workers case, are wholly lacking here. We do not hold that conspiracies to obstruct or prevent transportation in interstate commerce can in no circumstances be violations of the Sherman Act. Apart from the Clayton Act it makes no distinction between labor and non-labor cases. We only hold now, as we have previously held both in labor and non-labor cases, that such restraints are not within the Sherman Act unless they are intended to have, or in fact have, the effects on the market on which the Court relied to establish violation in the Second Coronado case. Unless the principle of these cases is now to be discarded, an impartial application of the Sherman Act to the activities of industry and labor alike would seem to require that the Act be held inapplicable to the activities of respondents which had an even less substantial effect [513]*513oil the competitive conditions in the industry than the combination of producers upheld in the Appalachian Coals case and in others on which it relied.28
If, without such effects on the market, we were to hold that a local factory strike, stopping production and shipment of its product interstate, violates the Sherman law, practically every strike in modern industry would be brought within the jurisdiction of the federal courts, under the Sherman Act, to remedy local law violations. The Act was plainly not intended to reach such a result, its language does not r'equire it, and the course of our decisions precludes it. The maintenance in our federal system of a proper distribution between state and national governments of police authority and of remedies private and public for public wrongs is of far-reaching importance. An intention to disturb the balance is not lightly to be imputed to Congress. The Sherman Act is concerned with the character of the prohibited restraints and with their effect on interstate commerce. It draws no distinction between the restraints effected by violence and those achieved by peaceful but oftentimes quite as effective means. Restraints not within the Act, when achieved by peaceful means, are not brought within its sweep merely because, without other differences, they are attended by violence.
Affirmed.