[41]*41Mr. Justice Sutherland-
delivered the opinion of the Court.
Petitioners, Bedford Cut Stone Company and 23 others, all, with one or two exceptions, Indiana corporations, are in the business of quarrying or fabricating, or both quarrying and fabricating, Indiana limestone in what is called the Bedford-Bloomirigton District in the State of Indiana. Their combined investment is about $6,000,000, and their annual aggregate sales amount to about $16,000,000, more than 75% of which are made in interstate commerce to customers outside the State of Indiana. The Journeymen Stone Cutters’ Association of North America, sometimes called and hereinafter referred to as the “ General Union,” is an association of mechanics engaged in the stone-cutting trade. It has a constitution, by-laws and officers, and an income derived from assessments upon its members. • Its principal headquarters are in Indiana, and it has a membership of about 5,0(30 persons, divided into over 150 local unions located in various states and in Canada, each of such local unions having its own by-laws, officers, and income derived from like assessments. By virtue of his membership, each member of these local unions is a member of the General Union. The members of the General Union and allied locals throughout the United States are stone cutters, carvers, curb cutters, ^curb setters, bridge cutters, planermen, lathemen, and carborundum moulding machine operators, engaged, in the cutting, patching and fabrication of all natural and artificial stones; and the General Union claims jurisdiction over all of them.
This suit was brought by petitioners against the General Union and some of its officers, and a number of affiliated local unions and some of their officers, to enjoin [42]*42them from combining and conspiring together to commit, and from committing, various acts in restraint of interstate commerce in violation of the federal Anti-Trust Act, c. 647, 26 Stat. 209, and to petitioners’ great and irreparable damage. The federal district court for the district of Indiana, after a hearing, refused a preliminary-injunction and, subsequently, on final hearing, entered a decree dismissing the bill for want of equity. On appeal, this decree was affirmed by the court of appeals upon the authority^ of an earlier opinion in the same case. 9 F. (2d) 40.
The facts, so far as necessary to be stated, follow. Limestone produced by petitioners is quarried and fabricated largely for building construction purposes. The stone is first taken' in rough blocks from the earth and, generally, then cut into appropriate sizes and sometimes planed. ■ Part of this product is shipped directly to. buildings, where it is fitted, trimmed and set in place, the remainder being sold in the rough to contractors to be fabricated. The. stone sold in interstate commerce comes into competition with other kinds of natural and artificial stone. The principal producers of artificial stone are unionized and are located outside of Indiana. Before 1921, petitioners carried on their work in Indiana under written agreement with the General Union, but since that time they have operated under agreements with unaffiliated unions, with the effect of closing their shops and quarries against the members of the General Union and its locals. Prior to the filing of the bill of complaint, the General Union issued a notice to all its locals and members, directing its members not to work on stone “ that has been started — planed, turned, cut, or semi-finished — by men working in opposition to our organization,” and setting forth that a convention of the union had determined that. “ members were to rigidly enforce the rule to keep off all- work started by men working in [43]*43opposition to our organization, with the exception of the work of - Shea-Donnelly, which firm holds an injunction against our association.” Stone produced by petitioners by labor eligible to membership in respondents’ unions was declared “ unfair ”; and the president of the General Union announced that the rule against handling such stone was to be promptly enforced in every part of the country. Most of the stone workers employed, outside the State of Indiana, on the buildings where petitioners’ product is used, are members of the General Union; and in most of the industrial centers, building construction is on a closed shop union basis.
The rule requiring members to refrain from working on “ unfair ” stone was persistently adhered to and effectively enforced against petitioner’s product, in a large number of cities and in many states. The evidence shows many instances of interference with the use of-petitioners’ stone by interstate customers, and expressions of apprehension on the part' of such customers of labor troubles if they purchased the stone. The President of the General • Union himself testified, in effect, that generally, the men were living up to the order and if it were shown to him that they did not do so in any place he would see that they did. Members found working on petitioners’ product, were ordered to stop and threatened with a revocation of their cards .if they continued; and the order of the General Union seems to have been enforced even when it’ might be against the desire of the local union. The transcript contains the record of a hearing upon these matters, before the Colorado Industrial Commission, from which it, appears that'in obedience to the order of the General Union its members .theretofore employed in Denver upon local building stopped work because petitioners’ product wás being used. The local contractor was notified merely that the men stopped work because the stone being used was [44]*44"unfair.” The contractor personally had no trouble of any kind with the union, and no other reason for the strike than that stated above existed. B. F. James, a member and an acting officer of the General Union testified that the local union in conducting its strike against a local builder had no choice in the matter; that they had their orders from the General Union with which they complied; that there was no difference or feeling whatever between the union and the local employer; that the fight was with the Bedford stone producers and they were trying to affect them through the local employer.
“ Q. And you people have no choice in the matter, you are just complying with the orders from the International [General Union]?
"A. We have no choice whatever.
"Q. Probably, if it was left up to you people here, knowing this employer as you do, why, your organization here, local organization, would not strike on this man?
“A. I don’t believe we would, no.
“Q. But you have got to follow the orders of your International organization?
“A. Yes, sir.”
The evidence makes plain that neither the General Union nor the locals had any grievance against any of the builders — local purchasers of the stone — or any other local grievance; and that the strikes were ordered and conducted for the sole purpose of preventing the use and, consequently, the sale and shipment in interstate commerce, of petitioners’ product, in order, by threatening the loss or serious curtailment of their interstate market, to force petitioners to the alternative of coming to undesired terms with the members of these unions. In 1924, the president of the General Union said:
“ The natural stone industry needs all the natural advantages it can possibly get, as there are so many kinds [45]*45of substitutes to take the natural stone’s place in the building material market, that it behooves the natural stone employers to do their utmost to see that no handicap is in its way, and it is a well known fact that when any material is known to have labor grievances, it retards that material in the building market, as the building public do not want the stigma on their building that it was built by ‘unfair labor,’ and they are also afraid of stoppage of work and unnecessary disputes while their budding is in course of construction, and no one can blame them for that.”
In the Colorado inquiry, the witness James further testified that the strike order did not make any allowance for stone theretofore ordered. “We were trying to affect the Bedford people through the local man.”
“Q. So the only person injured would be your own local man, who is your employer, and your personal friend, is that it?
“A. In a way. If it was finished that way, he would be the only one hurt. We are not fighting on this Denver man. We are trying to force these people through the other subcontractors all over the country.
“Q. You are trying to force the Bedford to employ members of your union to do this work?
“A. Yes, sir.
“Q. And irrespective of who it hurts, that is the object?
“A. That is the object. It is done from our headquarters.
“Q. Mr. Fernald, or anybody else, they have got to get out of the road, that is the object?
“A. We are trying to gain this point, irrespective of who it hurts.”
From a consideration of all the evidence, it is apparent that the enforcement of the general order to strike against petitioners’ product could have had no purpose other than [46]*46that of coercing or inducing the local employers to refrain from purchasing such product. To accept the assertion made here to the contrary, would be to say that the order and the effort to enforce it were vain and idle things without any rational purpose whatsoever. And indeed, on the argument, in answer to a. question from the bench, counsel for respondents very frankly said that, unless petitioners’ interstate trade in the so-called unfair stone were injuriously affected,, the strikes would accomplish nothing.
That the means adopted to bring about the contemplated restraint of commerce operated after physical transportation had ended is immaterial. Loewe v. Lawlor, 208 U. S. 274, 301; Boyle v. United States, 259 Fed. 803, 805-806. The product against which the strikes, were directed, it is true, had come to rest in the respective localities to which it had been, shipped,’ so that it had ceaséd to be a subject of interstate commerce, Industrial Assn. v. United States, 268 U. S. 64, 78-79; and interferences for a purely local object with its use, with no intention, express or implied, to restrain interstate commerce, it may be assumed, would not have been a violation of the Anti-Trust Act. Id., p. 77; United Mine Workers v. Coronado Co., 259 U. S. 344, 410-411. But these interferences were not thus in pursuit of a local motive, — they had for their primary aim restraint of the interstate sale and shipfnent of the commodity. Interstate commerce was the direct object of attack “ for the sake of which the several specific acts and courses of conduct [were] done and' adopted.” And the restraint of such commerce was the necessary consequence of the acts and conduct and the immediate end in. view. Swift & Co. v. United States, 196 U. S. 375, 397. Prevention of the use of petitioners’ product, which, without more, might have been a purely local matter, therefore, was only a part of the conspiracy, which must be construed as an [47]*47entirety; and, when so regarded, the local transactions become a part of the general plan and purpose to destroy or narrow petitioners’ interstate trade. Montague & Co. v. Lowry, 193 U. S. 38, 45—46. In other words, strikes against the local use of the product were simply the means adopted to effect the unlawful restraint. And it is this result, not the means devised to secure it, which gives character to the conspiracy.
Respondents’ chief contention is that “ their sole and only purpose . . . was to unionize the cutters and carvers of stone at the quarries.” And it may be conceded that this was the ultimate end in view. But how was that end to be effected? The evidence shows indubitably that it was by an attack upon the use of the product in other states to which it had been and was being shipped, with the intent and purpose of bringing about the loss or serious reduction of petitioners’ interstate business, and thereby forcing compliance with the demands of the unions. And, since these strikes were directed against the use of petitioners’ product in other states, with the plain design of suppressing or narrowing the interstate market, it is no answer to say that the ultimate object to be accomplished was to bring about a change of conduct on the part of petitioners in respect of the employment of union members in Indiana. A restraint of interstate commerce cannot be justified by the fact that the ultimate object of the participants was to secure an ulterior benefit which they might have been at liberty to pursue by means not involving such restraint. Anderson v. Shipowners Association, 272 U. S. 359; Duplex Co. v. Deering, 254 U. S. 443, 468; Ellis v. Inman, Poulsen & Co., 131 Fed. 182, 186.
The case therefore, is controlled, not by United Mine Workers v. Coronado Co., supra, and United Leather Workers v. Herkert, 265 U. S. 457, as respondents contend, but by others presently to be discussed. In the United Leather Workers case, it appeared that the strikes [48]*48were levelled only against production, and that the strikers (p. 471) “ did nothing which in any way directly interfered with the interstate transportation or sales of the complainants’ product;” and the decision rests upon the ground that there was an entire absence of evidence or circumstances to show that the defendants, in their conspiracy to coerce complainants, were directing their scheme against interstate commerce. United Mine Workers v. Coronado Co., supra, pp. 408-409, is to the same effect.
But in the second United Mine Workers case, 268 U. S. 295, 310, this court found sufficient evidence, even where the strike was directed against production, of an intent to restrain interstate commerce, and said:
“ The mere reduction in the supply of an article to be shipped in interstate commerce by the illegal or tortious prevention of its manufacture or production is ordinarily an indirect and remote obstruction to that commerce. But when the intent of those unlawfully preventing the manufacture or prbduction is shown to be to restrain or control the supply entering and moving in interstate commerce, or the price of it in interstate markets, their action is a direct violation of the Anti-Trust Act.”
In the present' case, since the strikes were directed against the use of the product in other states, with the immediate purpose and necessary effect of restraining future sales and shipments in interstate commerce, the determinative decisions to be applied are those pointed out in the United Leather Workers case, at p. 469:
“In Loewe v. Lawlor, 208 U. S. 274, and in Duplex Co. v. Deering, 254 U. S. 443, members of labor unions having a controversy with their employers sought to embarrass the sales by their employers of the product of their manufacture in other States by boycott and otherwise. They were held guilty of a conspiracy against interstate com[49]*49merce because of their palpable intent to achieve their purpose by direct obstruction of that commerce.”
Respondents cite and rely upon Hopkins v. United States, 171 U. S. 578, and Anderson v. United States, 171 U. S. 604. But of those cases we need say no more than that they involved agreements which neither in purpose nor in necessary result related to or had any direct effect upon interstate commerce.
With a.few changes in respect of the product involved, dates, names and incidents, which would have no effect upon the principles established, the opinion in Duplex Co. v. Deering, supra, might serve as an opinion in this case. The object of the boycott there was precisely the same as it is here, and the interferences with interstate commerce, while they were more numerous and more drastic, did not differ in essential character from the interferences here. A short statement of the case will make this clear.
The complainant was a manufacturer of printing presses and conducted its business on the “ open shop ” policy. There had been an unsuccessful strike to enforce the “ closed shop,” the eight-hour day and the union scale of wages. The strikers and the local organizations to which they belonged were affiliated- with an international association having a membership of more than sixty thousand. They entered into a combination to restrain complainant’s interstate trade by means of a “ secondary boycott,” in pursuance of which complainant’s customers in another state were warned not to purchase, install or operate its printing presses and threatened with loss and sympathetic strikes should they do so. The strikers threatened a trucking company with trouble if it should haul the presses; incited employees of the trucking company and other men employed by complainant’s customers to strike in order to interfere with the hauling and [50]*50installation of presses; notified repair shops not to do repair work on the presses; threatened union men with loss of union cards and the blacklist if they assisted in installing the presses; and resorted to other methods of preventing the sale and delivery of complainant’s presses in interstate commerce.
This court held that complainant’s business of manufacturing presses and disposing of them in commerce was a property right entitled to protection against unlawful injury or interference; that unrestrained access to the channels of interstate commerce was necessary for the successful conduct of that business; and that the combination to hinder and obstruct such commerce by the means indicated was in violation of the Sherman Anti-Trust Act, as amended by the Clayton Act. The combination was held to constitute a “ secondary boycott,” defined as “ a combination not merely to refrain from dealing with complainant, or to advise or by peaceful means persuade complainant’s customers to refrain ('primary boycott’), but to exercise coercive pressure upon such customers, actual or prospective, in order to cause them to withhold or withdraw patronage from complainant through fear of ■loss or damage to themselves should they deal with it.” Whether either kind of boycott was lawful or unlawful at common law was held to be immaterial, and the distinction between a primary and a secondary boycott was only important to be considered upon the question of the proper construction of the Clayton Act; and, as to that, it was distinctly determined that the Clayton Act was not intended to legalize the secondary boycott.
The court further held (p. 467-468) that by prior decisions of this court, it had been settled that a restraint of interstate commerce produced by peaceable persuasion was as much within the prohibition of the Anti-Trust Act as one accomplished by force or threats of force, and that there was nothing in § 20 of the Clayton Act (p. 473 [51]*51et seq.) which modified that rule as applied to the case tinder review or justified a resort to the secondary boycott. And it was said (p. 477) that the harmful'consequences of the opposite construction, adopted by the court below, were illustrated by that case where an ordinary controversy in a manufacturing establishment, concerning terms and conditions of employment there, had been held a sufficient occasion for imposing a general embargo upon the products of the establishment and a nation-wide blockade pf the channels of interstate commerce against them. The conclusion was reached that complainant was entitled to an injunction under the Sherman Act as amended by the Clayton Act, and that it was unnecessary to consider whether a like result would follow under the common law or local statutes. Finally, it is important to note (p. 478) the scope of the injunction which was authorized. Not only were the association and its members to be restrained from interfering with the sale, transportation, or delivery in interstate commerce of the presses, but also from interfering with the “ carting, installation, use, operation, exhibition, display, or repairing of any such press' or presses, . . . and especially from using any force,'threats, command, direction, or even persuasion with the object or having the effect of causing any person or persons to. decline employment, cease employment., or not seek employment, or to refrain from work or cease working under any person, firm, or corporation being a purchaser or prospective purchaser of any printing press or presses from complainant, . . .”
Loewe v. Lawlor, supra-, also dealt with a secondary boycott. The case arose before the enactment of the Clayton Act, but, in view of what has just been said, that is not important. .The defendants, certain labor organizations and the members thereof, undertook to compel complainants to unionize their factory. Being unsuccessful, the members of the labor organizations withdrew from com[52]*52plainants’ service and endeavored to persuade others to do the same. Defendants then declared a boycott against hats manufactured by complainants found in the-hands of their customers in other states, with the purpose and intent to destroy or curtail complainants’ market in other states and, thereby coerce compliance with defendants’ demands. This was held (pp. 292-294) to be a combination falling “ within the class of restraints of trade aimed at compelling third parties and strangers involuntarily not to engage in the course of trade except on conditions that the combination imposes,” and an unlawful restraint of interstate commerce as defined by the Anti-Trust Act. Referring to earlier cases, it was said (p. 297) that the Anti-Trust Act had a broader application than the prohibition of restraints of trade unlawful at common law, and that its effect was to declare illegal “ every contract, combination or conspiracy, in whatever form, of whatever nature, and whoever may be the parties to it, which directly or necessarily operates in restraint of trade or commerce among the several States.”
In United States v. Brims, 272 U. S. 549, a criminal case, this court dealt with a combination of manufacturers, contractors and carpenters in Chicago, having for its object the destruction of the competition of nonunion mills in Wisconsin and elsewhere by the employment in Chicago of union carpenters only, with the.understanding that they would refuse to install nonunion-made mill-work. There was evidence tending to show that so-called outside competition was cut down and thereby interstate commerce directly and materially impeded, and that this result was within the intention of the combination, which, upon these facts, was held to be in violation of the AntiTrust Act.
In Gompers v. Bucks Stove & Range Co., 221 U. S. 418, 438-439, this court said that the restraining powers of the courts extend to every device whereby commerce is ille[53]*53gaily restrained; and that — “ To hold that the restraint of trade under the Sherman anti-trust act, or on general principles of law, could be enjoined, but that the means through which the restraint was accomplished could not be enjoined would be -to render the law impotent.”
In cases arising outside the Anti-Trust Act, involving strikes like those here under review against so-called unfair products, there is a sharp conflict of opinion. On the one hand, it is said that such a strike is justified on the ground of self-interest; that the injury to the producer is inflicted, not maliciously, but in self-defense; that the refusal of the producer to deal with the union and to observe its standards threatens the interest of all its members and the members of the affiliated locals; and that a strike against the unfair material is a mere recognition of this unity of interest, and in refusing to work on such material the union is only refusing to aid in its own destruction. The opposite view is illustrated by such cases as Toledo, etc., Ry. Co. v. Pennsylvania Co., 54 Fed. 730; Thomas v. Cincinnati, etc., Ry. Co., 62 Fed. 803, 817, et seq.; Moores v. Bricklayers’ Union, 23 Wkly. Cin. Law Bull. 48 (affirmed by the Supreme Court of Ohio without opinion); Burnham v. Dowd, 217 Mass. 351; Purvis v. United Brotherhood, 214 Pa. St. 348; Booth & Brother v. Burgess, 72 N. J. Eq. 181, 188, 196; Piano & Organ Workers v. P. & O. Supply Co., 124 Ill. App. 353.
But with this conflict we have no concern in the present case. The question which it involves was presented and considered in the Duplex Co. case, supra, as the prevailing and the dissenting opinions show; and there it was plainly held that the point had no bearing upon the. enforcement of the Anti-Trust Act, and that since complainant had a clear right to an injunction under that Act as amended by the Clayton Act, it was “ unnecessary to consider whether a like result would follow under the common law or local statutes.”
[54]*54Whatever may be said as to the motives of the respondents or their general right to combine for the purpose of redressing alleged grievances of their fellow craftsmen or of protecting themselves or their organizations, the present combination deliberately adopted a course of conduct which directly and substantially curtailed, or threatened thus to curtail, the natural flow in interstate commerce of a very large proportion of the building limestone production of the entire country, to the gravely probable disadvantage of producers, purchasers and the public; and it must be held to be a combination in undue and unreasonable restraint of such commerce within the meaning of the Anti-Trust Act as interpreted by this court. An act which lawfully might be done by one, may when done by many acting in concert take on the form of a conspiracy and become a public wrong, and may be prohibited if the result be hurtful to the public or to individuals against whom such concerted action is directed, Grenada Lumber Co. v. Mississippi, 217 U. S. 433, 440; and any suggestion that such concerted action here may be justified as a necessary defensive measure is completely answered by the words of this court in Eastern States Lumber Ass’n v. United States, 234 U. S. 600, 613, that “Congress, with the right to control the field of interstate commerce, has so legislated as to prevent resort to practices which unduly restrain competition or unduly obstruct the free flow of such commerce, and private choice of means must yield to the national authority thus exerted.”
The record does not disclose whether petitioners at the time of bringing suit had suffered actual injury; but that is not material. An intent to restrain interstate commerce being shown, it is enough to justify equitable interposition by injunction if there be a dangerous probability that such injury will happen; and this clearly appears. The Anti-Trust Act “ directs itself against that dangerous probability as well as against the completed result.” Swift [55]*55& Co. v. United States, supra, p. 396; Vicksburg Waterworks Co. v. Vicksburg, 185 U. S. 65, 82; Thomson Machine Co. v. Brown, 89 N. J. Eq. 326, 328.
From the foregoing review, it is manifest that the acts and conduct of respondents fall within the terms of the Anti-Trust Act; and petitioners are entitled to relief by injunction under § 16 of the Clayton Act, c. 323, 38 Stat. 730, 737, by which they are authorized to sue for such relief “ against threatened loss or damage by a violation of the anti-trust laws,” etc. The strikes, ordered and carried out .with the sole object of preventing the use and installation of petitioners’ product in other states, necessarily threatened to destroy or narrow petitioners’ interstate trade by taking from them their customers. That the organizations, in general purpose and in and of themselves, were lawful and that the ultimate result aimed at may not have been illegal in itself, are beside the. point. Where the means adopted are unlawful, the innocent general character of the organizations adopting them or the lawfulness of the ultimate end sought to be attained, cannot serve as a justification.
Decree reversed.