delivered the opinion of the court.
This was a suit in equity, commenced October 24,1907, in the United States Circuit (afterwards District) Court for the Northern District of West Virginia, by the Hitch-man Coal & Coke Company, a corporation organized under the laws of the State of West Virginia, against certain citizens of the State of Ohio, sued individually and also as officers of the United Mine Workers of America. Other non-citizens of plaintiff's State were named as defendants but not served with process. Those who were served and who answered the bill were T. L. Lewis, Vice President of the U. M. W. A. and of the International Union U. M. W. A.; William Green, D. H. Sullivan, and “George” W. Savage, (his correct Christian name is Gwilym), respectively President, Vice President, and Secretary-Treasurer of District No. 6, U. M. W. A.; and A. R. Watkins, John Zelenka, and Lee Rankin, respectively President, Vice President and Secretary-Treasurer of Sub-district No. 5 of District No. 6.
*233Plaintiff owns about 5,000 acres of' coal lands situate at or near Benwood, in Marshall County, West Virginia, and within what is known as the “Pan Handle District” of that State, and operates a coal mine thereon, employing between 200 and 300 men, and having an annual output, in and before 1907, of about 300,000 tons. At the time of the filing of the bill, and for a considerable time before and ever since, it operated its mine “non-union,” under, an agreement with its men to the effect that the mine should be run on a non-union basis, that the employees should not become connected with the Union while employed by plaintiff, and that if they joined it their employment with plaintiff should cease. The bill set forth these facts, inter alia, alleged that they were known to defendants and each of them, and “that the said defendants have unlawfully and maliciously agreed together, confederated, combined and formed- themselves into a conspiracy, the purpose" of which they are proceeding to carry out and are now about to finally accomplish, namely: to cause your orator’s mine to be shut down, its plant to remain idle, its contracts to be broken and unfulfilled, until such time as your orator shall submit to the demand of the Union that it shall unionize its plant, and having submitted' to such demand unionize its plant by employing only union men who shall become subject to the orders of the Union,” etc. The general object of the bill was to obtain an injunction to restrain defendants from interfering with the relations existing between plaintiff and its employees in order to compel plaintiff to “unionize” the mine.
A restraining order having been granted, followed by a temporary injunction, the served defendants filed answers, and thereupon made a motion to modify the injunction, which was refused. 172 Fed. Rep. 963. An appeal taken by defendants from this order was dismissed by the Circuit Court of Appeals. 176 Fed. Rep. 549. Afterwards *234they applied for and obtained leave to withdraw their answers and file others; the order, however, prescribed that the withdrawn answers were “not to be removed from the file.” The new answers denied all material averments of the bill, some of which had been admitted in the former answers. Plaintiff, having filed replications, obtained an order that the former answers should be treated as evidence on behalf of the plaintiff upon the issue joined. Upon this evidence and other evidence introduced before the court orally, the case was submitted, with the result that a final decree was made January 18, 1913, granting a perpetual injunction. 202 Fed. Rep. 512. This was reversed by the Circuit Court of Appeals June 1, 1914 (214 Fed. Rep. 685), but the mandate was stayed pending an application to this court for a writ of certiorari. Afterwards an appeal was allowed. This court dismissed the appeal, but. granted the writ of certiorari (241 U. S. 644), the record on appeal to stand as a return.
The final decree of the District Court included an award of injunction against John Mitchell, W. B. Wilson, and Thomas Hughes, who while named as defendants in the bill were not served with process and entered no appearance except to object to the jurisdiction of the court over them. Under the federal practice, the appearance to object did not bind these parties to submit to the jurisdiction on the overruling of the objection (Harkness v. Hyde, 98 U. S. 476, 479; Southern Pacific Co. v. Denton, 146 U. S. 202, 206; Mexican Central Ry. Co. v. Pinkney, 149 U. S. 194, 209; Goldey v. Morning News, 156 U. S. 518; Davis v. C., C., C. & St. L. Ry. Co., 217 U. S. 157, 174), and since the injunction operates only in personam, it was erroneous to include them as defendants. It also was erroneous to include personal relief by injunction against certain named parties who, pending suit, were chosen to succeed some of the original defendants as officers of the international,, district, and sub-district *235unions, but who were not served with process and did not appear, they being included upon the ground that they were “before the court by representation through service having been had upon their said predecessors in office.” This suit was commenced, and was carried to final decree in the trial court, before the taking effect of-the present Equity Rules (226 U. S. 629), and hence is governed by the former Rule 48 (210 U. S. 524), under which the rights of absent parties were expressly reserved.
But these procedural difficulties do not affect that part of the decree which awarded an injunction against the answering defendants (Lewis, Green, Sullivan, Savage, Watkins, Zelenka, and Rankin) “individually” and not as officers of the Union or its branches except as to Savage, against whom the decree goes in both his individual and official capacities, he alone having retained at the time of the final decree the same office he held at the beginning of the suit. If there was error in excluding the “official” responsibility of the others, it was not one of which they could complain, and it was not assigned for error upon their appeal to the Circuit Court of Appeals. If they were subject to injunction at all, they were so in their individual capacities. Whether the decree will bind their successors in office, or their fellow-members of the Union, is a question to be determined hereafter, if and when proceedings are taken to enforce the injunction against parties other than the answering defendants.
We proceed, therefore, to consider the case as it stands against the answering defendants.
The District Court based its decision upon two grounds: (1) That the organization known as the United Mine Workers of America, and its branches, as conducted and managed at the time of the suit and for many years before, was a common-law conspiracy in unreasonable restraint of trade, and also and especially a conspiracy against the rights of non-union miners in West Virginia; *236and (2) That the defendants, in an effort to compel the plaintiff to enter into contractual relations with the Union relating to the employment of labor and the production of coal, although having knowledge of express contracts existing between plaintiff and its employees which excluded relations with the Union, endeavored by unlawful means to procure a breach of these contracts by the employees.
A brief recital of previous transactions between the parties becomes material. The Union is a voluntary and unincorporated association which was organized in the year 1890 in the States of Ohio and Indiana, and after-wards was extended to other States. It is made up of national or “international,” district, sub-district, and local unions. District No. 6 comprises the coal districts of Ohio and the Panhandle of West Virginia. Sub-district No. 5 of that district comprises five counties and parts of counties in Ohio, and the Panhandle.
The answering defendants were and are active and influential members — -leaders—of the Union, as well as officers. Savage, .Lewis, and Sullivan have been members from its formation in 1890, and have held important offices in it and attended the national conventions. The others are long-time members, and possessed an influence indicated by the offices they held, but not limited to the duties of those offices.
From 1897 to 1906 what were known as joint interstate conferences were held annually or biennially between officials of the Union and representatives of the operators in the “Central Competitive Field” (which includes Western Pennsylvania, Ohio, Indiana, and Illinois, but not West Virginia), .for the purpose of agreeing upon the scale of wages and the conditions of employment in that field. In addition there were occasional conferences of the same character affecting other States and districts.
*237Plaintiff’s mine is within the territorial limits of Sub-district No. 5 of District No. 6. Coal-mining operations were commenced there in the early part of the year 1902, and the mine was operated "non-union” until April, 1903, when, under threats from the Union officials, including defendants Watkins and Sullivan, that a certain unionized mine in Ohio, owned by the same proprietors, would be closed down if the men at the Hitchman were not allowed to organize, plaintiff consented to the unionization of the latter mine. This went into effect on the 1st of-April, 1903, and upon the very next day the men were called out on strike because of a disagreement with the company as to the basis upon which mining should be paid for. The strike continued until May 23, requiring plaintiff to cease operations and preventing it from -fulfilling its contracts, the most important of which was one for the daily supply of engine coal to the Baltimore & Ohio Railroad at a .coaling station adjoining the .miné. The financial loss to plaintiff was serious. The strike was settled and the men resumed work upon the basis of a modification of the official mining scale applicable to the Hitchman mine.
Again, in the spring of 1904, there was difficulty in renewing the scale. A temporary scale, agreed- upon between operators and miners for the month of April, 1904, was signed in behalf of the Hitchman Company on the 18th of April. Two days later the men at the Hitchman struck, and the mine remained idle for two months, during which time plaintiff sustained serious losses in business and was put to heavy expense in obtaining coal from other sources to fill its contract with the Baltimore & Ohio Railroad Company. The strike was settled by the adoption of the official scale for the Panhandle District, with amendatory local rules for the Hitchman mine.
After this there was little further trouble until April 1, *2381906, when a disagreement arose between the Union and an association of operators with which plaintiff was not connected — the association being in fact made up of its competitors — about arranging the terms of the scale for the ensuing two years. At the same time a similar disagreement arose between the operators and the Union officials in the Central Competitive Field. The result was a termination of the interstate conferences and a failure to establish any official scale for the ensuing two years, followed by a widespread strike, or a number of concurrent strikes, involving the most of the bituminous coal-producing districts. There was absolutely no grievance or ground of disagreement at the Hitchman mine, beyond the fact that the mining scale expired by its own terms on March 31, and the men had not received authority from the Union officials either to renew it' or to agree to a new one in its place. Plaintiff came to an understanding with the local union to the effect that if its men would continue at work the company would pay them from April 1st whatever the new scale might be, except that if the new scale should prove to be lower than that which expired on March 31, there should be no reduction in wages, while if the scale was raised the company would pay the increased amount, dating it back to April 1st. This was satisfactory to the men; but as the question of a new scale was then under discussion at a conference between the officials of the Union and the representatives of the Operators’ Association, and plaintiff’s employees wished to get the sanction of their officers, the manager of the Hitchman mine got into communication with those officials, including defendant Green, President of District No. 6, and endeavored to secure their assent to the temporary arrangement, but without success. Then a committee of the local union, including Daugherty, its President, took up the matter with Green and received permission to mine and load engine coal *239until further notice from him. Under this arrangement the men remained at work for about two weeks. On April 15th, defendant Zelenka, .Vice President of the sub-district, visited the mine, called a meeting of the miners, and addressed them in a foreign tongue, as a result of which they went on strike the next day, and the mine was shut down until the 12th of June, when it resumed as a “non-union” mine, so far as relations with the U. M. W. A. were concerned.
During this strike plaintiff was subjected to heavy losses and extraordinary expenses with respect to its business, of the same kind that had befallen it during the previous strikes.
About the 1st of June a self-appointed committee of employees called upon plaintiff’s president, stated in substance that they could not remain longer on strike because they were not receiving benefits from the Union, and asked upon what terms they could return to work. They were told that they could come back, but not as members of the United Mine Workers of America; that thenceforward the mine would be run nomunion, and the company would deal with each man individually. They assented to this, and returned to work on a non-union basis. Mr. Pickett, the mine superintendent, had charge of employing the men, then and afterwards, and to each one who applied for employment he explained the conditions, which were that while the company paid the wages demanded by the Union and as much as anybody else, the mine was run non-union and would continue so to run; that the company would not recognize the United Mine Workers of America; that if any man wanted to become a member of that union he was at liberty to do so; but he could not be a member of it and remain in the employ of the Hitchman Company; that if he worked for the company he would have to work as a non-union man. To this each man employed gave his assent, un*240derstanding that while he worked for the company he must keep out of the Union.
Since January, 1908 . (after the commencement of the suit), in addition to having this verbal understanding, each man has been required to sign an employment card expressing in substance the same- terms. This has neither enlarged nor diminished plaintiff’s rights, the agreement not being such as is required by law to be in writing.
Under this arrangement as to the terms of employment, plaintiff operated its mine from June 12, 1906, until the commencement of the suit in the fall of the following year.
During the same period a precisely similar method of employment obtained at the Glendale mine, a property consisting of about 1,200 acres of coal land'adjoining the Hitchman property on the south, and operated by a company having the same stockholders and the same management as the Hitchman; the office of the Glendale mine being at the Hitchman Coal & Coke Company’s office. Another mine in the Panhandle, known as the Richland, a few miles north of the Hitchman, likewise was run “non-union.”
In fact, all coal mines in the Panhandle and elsewhere in West Virginia, except in a small district known as the Kanawha field, were run “non-union,” while the entire industry in Ohio-, Indiana, and Illinois was operated on the “closed-shop” basis, so that no man could hold a job about the mines unless he was a member of the United •Mine Workers of America. Pennsylvania occupied a middle ground, only a part of it being under the jurisdiction of the Union. Other States need not be particularly mentioned.
The unorganized condition of the mines in the Panhandle and some other districts was recognized as a serious interference with the purposes of the Union in the *241Central Competitive Field, particularly as it tended to keep the cost, of production low, and, through competition with coal produced in the organized field, rendered it more difficult for the operators there to maintain prices high enough to induce them to grant certain concessions demanded by the Union. This was the subject. of earnest and protracted discussion in the annual international convention of the U. M. W. A. held at Indianapolis, Indiana, in the month of January, 1907, at which all of the answering defendants were present as delegates and participated in the proceedings. The discussion was based upon statements contained in the annual reports of John Mitchell, as President of the Union (joined as a defendant in the bill but not served with process), and of defendant Lewis, as Vice President, respecting the causes and consequences of the strike of 1906, and the policy to be adopted by the Union for the future. In these reports it was made to appear that the strike had been caused immediately by the failure of the joint convention of operators and miners representing the central and southwestern competitive fields, held in the early part of the year 1906, to coupe to an agreement for a renewal of the mining scale; that the strike was widespread, involving not less than 400,000 mine workers, was terminated by "district settlements,” with variant results in different parts of the territory involved, and had not been followed by a renewal of the former relations between the operators and miners in the Central Competitive Field. Another result of the strike was a large decrease in the membership of the Union. Two measures of relief were proposed: first, that steps be taken to reestablish the joint interstate conferences; and second, the organization of the hitherto unorganized fields, including the Panhandle District of West Virginia, under closed-shop agreements, with all men about the mines included in the membership of the United Mine Workers. *242of America. In the course of the discussion the purpose of organizing West Virginia in the interest of the unionized mine workers in the Central Competitive Field, and the probability that it could be organized only by means of strikes, were repeatedly declared and were disputed by nobody. All who spoke advocated strikes, differing only as to whether these should be nation-wide or sectional. Defendant Lewis, in his report, recommended an abandonment of. the policy of sectional settlements which had been pursued in the previous year. This recommendation, interpreted as a criticism of the policy pursued under the leadership of President Mitchell in the settlement of the 1906 strike, was the subject of long and earnest debate, in the course of which Lewis said: “When we organize West Virginia, when we organize the unorganized sections of Pennsylvania, we will organize them by a strike movement.” And again, towards the close of the debate: “No one has made the statement that we can organize West Virginia without a strike.” Defendant Green took part, favoring the view of Mr. Lewis that strikes should be treated nationally instead of sectionally. In the course of his remarks he said: “I say to you, gentlemen, one reason why I opposed the policy that was pursued last year was because over in Ohio we were peculiarly situated. We had West Virginia on the south and Pennsylvania on the east, and after four months of a strike in eastern Ohio we had reached the danger line. We felt keenly the competition from West Virginia, and during the suspension our mines in Ohio chafed under the object lesson they had. They saw West Virginia coal go by, train-load after train-load passing their doors, when they were on strike. This coal supplied the markets that they should have had. There is no disguising the fact, something must be done to remedy this condition. Year after year Ohio has had to go home and strike in some portion of the district to enforce the *243interstate agreement that was signed up here. . . . I confess here and now that the overwhelming sentiment in Ohio was that a settlement by sections would not correct the conditions we complained of. Now, something must be done; it is absolutely necessary to protect us against the competition that comes from the unorganized fields east of us.” Mr. Mitchell opposed the view of defendant Lewis, reiterating an opinion, repeatedly expressed before, that West Virginia and the other unorganized fields, “would not be thoroughly organized except as the result of a successful strike”; but declaring that “they will not be organized at all, strike or no strike, unless we are able to support the men in those fields from the first day they lay down their tools. . . . Now, I believe it is possible, , indeed I believe it is probable, that in the not distant future we will be able to inaugurate a movement in West Virginia and the other unorganized fields that will involve them in a strike, and then we will expect you to furnish the sinews of war, as you have done in the past, to keep these men in idleness.”
The discussion continued during three days, and at the end of it the report of a committee which expressed disagreement with Vice President Lewis’ opposition to sectional settlements and recommended “a continuation in the future of the same wise, conservative business-like policies” that had been pursued by President Mitchell, was adopted by a viva voce vote.
The plain effect of this action was to approve a policy which, as applied to the concrete case, meant that in order to relieve the union miners of Ohio, Indiana, and Illinois from the competition of the cheaper product of the non-union mines of West Virginia, the West Virginia mines should be “organized” by means of strikes local to West Virginia, the strike benefits to be paid by assessments upon the union miners in the other States mentioned, while they remained at work.
*244This convention was followed by an annual convention of. Sub-district 5 of District 6, held in the month of March, 1907, at which defendants Watkins and Rankin were present as President and Secretary of the sub-district. Defendant Lewis, as National Vice President, occupied the chair during several of the sessions. Defendant Zelenka was present as a delegate, and also Thomas Hughes, who, while named as a defendant in the present suit, was not served with process. Watkins and Rankin in their reports recommended the complete unionization of the mines in the Panhandle counties, with particular reference to the Hitchman, the Glendale, the Richland, and two others; and as a result it was resolved “that the Sub-District officers, together with the District officers, be authorized to take up the work of. organizing every mine in the Sub-District as quickly as it can be done.”
Evidently in pursuance of this resolution, defendants Green, Zelenka, and Watkins, about July 1, 1907, called at plaintiff’s office and laid before its general manager, Mr. Koch, a proposition for the unionization of the mine. He declined , to consider it, but at their request laid it before plaintiff’s board of directors, who rejected the proposition, and the manager informed Green of this In one of the interviews Koch informed these defendants of the terms of plaintiff’s working agreement with its employees to the effect that the mine was to be run non-union and they were not to become members of the Union.
About the same time, a Mr. McKinley, who was operating the Richland mine non-union, was interviewed by the Union leaders, notified of the resolution adopted by. the sub-district convention, and, having asked that his mine be let alone, was met with the threat that they would secure the support of his men, and that if he did not recognize the Union they would shut down his mine. *245In one of the interviews that ensued he was told'that it was their purpose to organize the Glendale, the Hitch-man, the Richland, and some other mines; that at the Glendale they had twenty-four men who had joined the organization, “and that they had sixty men who had signed up or had agreed to join the organization at Hitch-man, and that they were going to shut the mine down as soon as they got a few more men.” With respect to their progress at his own mine he was kept in the dark Until about the middle of October, 1907, when, through the activities of the organizer Hughes, they succeeded in shutting it down, and it remained closed until a restraining order was allowed by the court, immediately after which it resumed non-union.
The evidence renders it clear that Hughes was sent into the Panhandle to organize all the mines there, in accordance with the resolution of the sub-district convention. The bill made a statement of his activities, and alleged that he was acting as an organizer for the Union. Defendants’ final answers made a complete denial, but in this are contradicted by admissions made in the earlier answers and by other and undisputed evidence. The only defendant who testified upon the subject declared that Hughes was employed by District No. 6 as an organizer, but denied that he had power or authority to shut down the Hitchman mine..
He arrived at that mine some time in September, 1907, and remained there or in that vicinity until the latter part of October, conducting a campaign of organization at the Hitchman and at the neighboring Glendale and Richland mines.
The evidence shows that he had distinct and timely notice that membership in the Union was inconsistent with the terms of employment at all three mines, and a violation of the express provisions of the agreement at the Hitchman and Glendale.
*246Having unsuccessfully applied to Koch and McKinley for their cooperation, Hughes proceeded to interview as many of the men as he could reach and to hold public meetings in the interest of the Union. There is clear and uncontradicted evidence that he did not confine himself to mere persuasion, but resorted to deception and abuse. In his public speeches he employed abusive language respecting Mr. Pickett, William Daugherty, and Jim Jarrett.1 He prophesied, in such a way that ignorant, foreign-born miners, such as he was addressing, naturally might believe him to be speaking with knowledge, that the wages paid by the Hitchman would be reduced unless the mine was unionized. The evidence as to the methods he employed in personally interviewing the miners, while meagre, is significant. Myers, a Hitchman miner, testified: “He told me that he was a good friend of Mr. Koch, and that Mr. Koch had nothing against having the place organized again. He said he was a friend of his, and I made the remark that I would ask Mr. Koch and see if it was so; and he said no, that was of no use because he was telling me the truth.” He did not confine his attentions to men who already were in plaintiff’s employ, but in addition dissuaded men who had accepted employment from going to work.
A highly significant thing, giving character to Hughes’ entire course of conduct, is that while his solicitation of the men was more or less public, as necessarily it had to be, he.was careful to keep secret the number and the names of those who agreed to join the Union. Myers, being asked to allow his name to be entered on a book *247that Hughes carried, tried to see the names already entered, “but he would not show anything; he told me he had it, and I asked him how many names was on it, and he said he had about enough to 'crack off.’” To Stewart, another Hitchman miner, he said “he was forming a kind of secret order among the men; he said he had a few men — he did not state the number of them — and he said each man was supposed to give him so much dues to keep it going, and then he said after he got the majority he would organize the place.” Pickett, the mine superintendent, had learned of only five men at the Glendale who were inclined to join Hughes’ movement; but when these were asked to remain outside of the mine for a talk, fifteen other men waited with them, and upon being reminded that while the company would not try to prevent them from becoming memof the Union, they could not be members and at the same time work for the Glendale Company, they all accepted this as equivalent to a notice of discharge. And, as has been stated, the owner of the Richland, while repeatedly threatened with unionization, was kept in the dark as to the progress made by the organizer amongst his employees until the mine was actually shut down.
The question whether Hughes had “power or authority” to shut down the Hitchman mine is beside the mark. We are not here concerned with any question of ultra vires, but with an actual threat of closing down, plaintiff’s mine, made by Hughes while acting as agent of an organized body of men who indubitably were united in a. purpose to close it unless plaintiff would conform to their wishes with respect to its management, and who lacked the power to carry out that purpose only because they had not as yet persuaded a sufficient number of the Hitchman miners to join with them, and hence employed Hughes as an “organizer” and sent him to the mine with the very *248object of securing the support of the necéssary number of miners. They succeeded with respect to one of the mines threatened (the Richland), and preparations of like character were in progress at the Hitchman and the Glendale at the time the restraining order was made in this cause.
If there be any practical distinction between organizing the miners and organizing the mine, it has no application to this case. Unionizing the miners is but a step in the process of unionizing the mine, followed by the latter almost as á matter of course. Plaintiff is as much entitled to prevent the first step as the second, so far as its own employees are concerned, and to be protected against irreparable injury resulting from either. Besides, the evidence shows, without any dispute, that defendants contemplated no half-way measures, but were bent on organizing the mine, the “consent” of plaintiff to be procured through such a control of its employees as would render,any further independent operation of the mine out of the question. This is evident from the discussions and resolutions of the international and sub-district conventions, from what was said by defendants Green, Zelenka, and Watkins to plaintiff’s manager, and to the operator of the Richland, and from all that was said and done by Hughes in his effort to organize the Hitchman, Glendale, and Richland mines.
■ In short, at the time the bill was filed, defendants, although having full notice of the terms of employment^ existing between plaintiff and its miners, were engaged in an earnest effort to subvert those relations without plaintiff’s consent, and to alienate a sufficient number of the men to shut down the mine, to the end that the fear of losses through stoppage of operations might coerce plaintiff into “recognizing the union” at the cost of its own independence. The methods resorted to by their “organizer” were such as have been described. The legal consequences remain for discussion.
*249The facts we have recited are either admitted or else proved by clear and undisputed evidence and indubitable inferences therefrom. The proceedings of the international and sub-district conventions were shown by the introduction of official verbatim reports, properly authenticated. It is objected that these proceedings, especially in so far as they include the declarations and conduct of others than the answering defendants, are not admissible because the existence of a criminal or unlawful conspiracy is not made to appear by evidence aliunde. The objection is untenable. In order that the declarations and conduct of third parties may be admissible in such a case, it is necessary to show by independent evidence that there was a combination between them and defendants, but it is not necessary to show by independent evidence that the combination was criminal or otherwise unlawful. The element of illegality may be shown by the declarations themselves. The rule of evidence is commonly applied in criminal cases, but is of general operation; indeed, it originated in the law of partnership. It depends upon the principle that when any number of persons associate themselves together in the prosecution of a common plan or enterprise, lawful or unlawful, from the very act of association there arises a kind of partnership, each member being constituted the agent of all, so that the act or declaration of one¿ in furtherance of the common object, is the act of all, and is admissible as primary and original evidence against them. Pleasants v. Fant, 22 Wall. 116, 119; Connecticut Mutual Life Ins. Co. v. Hillmon, 188 U. S. 208, 218; Story Part., §§ 107, 108; 1 Greenleaf Ev., §§ 112, 113 (184 b, c); 2 Starkie Ev. (2d ed.) 25, 26; King v. Hardwick, 11 East, 578, 585, 589; Sandilands v. Marsh, 2 Barn. & Ald. 673, 679; Wood v. Braddick, 1 Taunt. 104, 105; Van Reimsdyk v. Kane (Story, J.), 1 Gall. 630, 635; 28 Fed. Cas. 1067, 1069; Aldrich v. Warren, 16 Maine, 465, *250468; Pierce v. Wood, 23 N. H. 519, 531; Page v. Parker, 40 N. H. 47, 62; State v. Thibeau, 30 Vermont, 100, 105; Jenne v. Joslyn, 41 Vermont, 478, 484; Locke v. Stearns, 1 Metc. 560, 563; Lowe v. Dalrymple, 117 Pa. St. 564, 568; Main v. Aukam., 4 App. D. C. 51, 56.
Upon a kindred principle, the declarations and conduct of an agent, within the scope and in the course of his agency, are admissible as original evidence against the principal, just as his own declarations or conduct would be admissible. Barreda v. Silsbee, 21 How. 146, 164, 165; Vicksburg & Meridian Railroad v. O'Brien, 119 U. S. 99, 104; LaAbra Silver Mining Co. v. United States, 175 U. S. 423, 498. And since the evidence of Hughes’ agency is clear and undisputed — that' as the representative of a voluntary association of which the answering defendants were active members, and in the execution of a purpose to which they all had given consent, and in which some of them were actively cooperating, he was engaged in an effort to organize the coal mines of the Panhandle District — it is equally clear that his declarations and conduct while so doing are evidential against the defendants.
What are the legal consequences of the facts that have been detailed?
That the plaintiff was acting within its lawful rights in employing its men only upon terms of continuing non-membership in the United Mine Workers of America is not open to question'. Plaintiff’s repeated costly experiences of strikes and other interferences while attempting to “run union” were a sufficient explanation of its resolve bo run “non-union,” if any were needed. But neither explanation nor justification is needed! Whatever may be the advantages of “collective bargaining,” it is not bargaining at all, in any just sense, unless it is voluntary on both sides. The same liberty which enables men to form unions, and through the union to enter into agree*251ments with employers willing to agree, entitles other men to remain independent of the union and other employers to agree with them to employ no man who owes any allegiance or obligation to the union. In the latter case, as in the former, the parties are entitled to be protected by the law in the enjoyment of the benefits of any lawful agreement they may make. This court repeatedly has held that the employer is as free to make non-membership in a union a condition of employment, as the working man is free to join the union, and that this is a part of the constitutional rights of personal liberty and,private property, not to be taken away even by legislation, unless through some proper exercise of the paramount police power. Adair v. United States, 208 U. S. 161, 174; Coppage v. Kansas, 236 U. S. 1, 14. In the present case, needless to say, there is no act of legislation to which defendants may resort for justification.
Plaintiff, having in the exercise of its undoubted rights established a working agreement between it and its employees, with the free assent of the latter, is entitled to be protected in the enjoyment of the resulting status, as in any other legal right. That the employment was “at will,” and terminable by either party at any time, is of no consequence. In Truax v. Raich, 239 U. S. 33, 38, this court ruled upon the precise question as follows: “It is said that the bill does not show an employment for a term, and that under an employment at will the complainant could be discharged at any time for any reason or for no reason, the motive of the employer being immaterial. The conclusion, however, that is sought to be drawn is too broad. The fact that the employment is at the will of the parties, respectively, does not make it one at the will of others. The employé has manifest interest in the freedom of the employer to exercise his judgment without illegal interference or compulsion, and, by the weight *252of authority, the unjustified interference of third persons is actionable although the employment is at will.” (Citing many cases.)
In short, plaintiff was and is entitled to the good will of its employees, precisely as a merchant is entitled to the good will of his customers although they are under no obligation to continue to deal with him. The value of the relation lies in the reasonable probability that by properly treating its employees, and paying them fair wages, and avoiding reasonable grounds of complaint, it will be able to retain them in its employ, and to fill vacancies occurring from time to time by the employment of other men on the same terms. The pecuniary value of such reasonable probabilities is ' incalculably great,- and is recognized by the law in a variety of relations. See Brennan v. United Hatters, (cited with approval in Truax v. Raich, supra,) 73 N. J. L. 729, 749; Brown v. Honiss, 74 N. J. L. 501, 514 et seq.; Jersey City Printing Co. v. Cassidy, 63 N. J. Eq. 759, 767; Walker v. Cronin, 107 Massachusetts, 555, 565-566; Moran v. Dunphy, 177 Massachusetts, 485, and cases there cited; L. D. Wilcutt & Sons Co. v. Driscoll, 200 Massachusetts, 110, 117, etc.
The right of action for persuading an employee ta leave his employer is universally recognized — nowhere more clearly than in West Virginia — and it rests upon fundamental principles of general application, not upon the English statute of laborers. . Thacker Coal Co. v. Burke, 59 W. Va. 253, 255; 8 Ann. Cas. 885, 886; Walker v. Cronin, 107 Massachusetts, 555, 567; Angle v. Chicago, St. Paul &c. Ry. Co., 151 U. S. 1, 13; Noice Adm'x, v. Brawn, 39 N. J. L. 569, 572.
We turn to the matters set up by way of justification or excuse for defendants’ interference with the situation existing at plaintiff’s mine.
The case involves no question of the rights of employees. *253Defendants, have no agency for plaintiff’s employees, nor do they assert any disagreement or grievance in their behalf. In fact, there is none; but, if there were, defendants could not, without agency, set up any rights that employees might have. The right of the latter to strike would not give to defendants the right to instigate a strike. The difference is fundamental.
It is suggested as a ground of criticism that plaintiff endeavored to secure a closed non-union mine through individual agreements with its employees, as if this furnished some sort of excuse for the employment of coercive measures to secure a closed union shop through a collective agreement with the Union. It is a sufficient answer, in law, to repeat that plaintiff had a legal and constitutional right to exclude union men from its employ. But it may be worth while to say, in addition: first, that there was no middle ground open to plaintiff; no option to have an ’’open shop” employing union men and non-union men indifferently; it was the Union that insisted upon closed-shop agreements, requiring even carpenters employed about a mine to be members of the Union, and making the employment of any nonunion man a ground for a strike; and secondly, plaintiff was in the reasonable exercise of its rights in excluding all union men from its employ, having learned, from a previous experience, that unless this were done union organizers might gain access to its mine in the guise of laborers.
Defendants set up, by way of justification or excuse, the right of workingmen to form unions, and to enlarge their membership by inviting other workingmen to join. The right is freely conceded, provided the objects of the union be proper and legitimate, which we assume to be true, in a general sense, with respect to the Union here in question. Gompers v. Bucks Stove & Range Co., 221 U. S. 418, 439. The cardinal error of defendants’ position lies *254in the assumption that the right is so absolute that it may be exercised under any circumstances and without any qualification; whereas in truth, like other rights that exist in civilized society, it must always be exercised with reasonable regard for the conflicting, rights of others. Brennan v. United Hatters, 73 N. J. L. 729, 749. The familiar maxim, Sic utere tuo ut alienum non Icedas— literally translated, “So use your own property as not to injure that of another person,” but by more proper interpretation, “so as not to injure the rights of another,” (Broom’s Leg. Max., 8th ed., 289) — applies to conflicting rights of every description. For example, where two or more, persons are entitled to use the same road or passage, each one in using it is under a duty to exercise care not to interfere with its use by the others, or to damage them while they are using it. And a most familiar application is the action for enticing an employee, in which it never was a justification that defendant wished to retain for himself the services of the ■ employee. 1 Black. Com. 429; 3 Id. 142.
Now, assuming defendants were exercising, through Hughes, the right to invite men to join their Union, still they had plain notice that plaintiff’s mine was run “nonunion,” that none of the men had a right to remain at work there after joining the Union, and that the observance of this agreement was of great importance and value both to plaintiff and to its men who had voluntarily made the agreement and desired to continue working under it. Yet defendants, far from exercising any care to refrain from unnecessarily injuring plaintiff, deliberately and advisedly selected that method of enlarging their membership which would inflict the greatest injury upon plaintiff and its loyal employees. Every Hitch-man miner who joined Hughes’ “secret order” and permitted his name to be entered upon Hughes’ list was guilty of a breach of his contract of employment and *255acted a lie whenever thereafter he entered plaintiff’s mine to work. Hughes not only connived at 'this, but must be deemed to have caused and procured it, for it was the main feature of defendants’ plan, the sine qua non of their programme. Evidently it was deemed to be necessary, in order to “organize the Panhandle by a strike movement,” that at the Hitchman, for example, man after man should be persuaded to join the Union, and having done so to remain at work, keeping the’ employer in ignorance of their number and identity, until so many had joined that by stopping work in a body they could coerce the employer and the remaining miners to “organize the mine,” that is, to make an agreement that none but members of the Union should be employed, that terms of employment should be determined by negotiation not with the employees but with union officers— perhaps residents of other States and employees of competing mines — and that all questions in controversy between the mine operator and the miners should likewise be settled with outsiders.
True, it is suggested that under the existing contract an employee was not called upon to leave plaintiff’s employ until he actually joined the Union, and that the evidence shows only an attempt by Hughes to induce the men to agree to join, but no attempt to induce them to violate their contract by failing to withdraw from plaintiff’s employment after actually joining. But in a court of equity, which looks to the substance- and essence of things and disregards matters of form and technical nicety, it is sufficient to say that to induce men to agree to join is but a mode of inducing them to join, and that when defendants “had sixty men who had signed up or agreed to join the organization at Hitchman,” and were “going to shut'the mine down as soon as they got a few more men,” the sixty were for practical purposes, and therefore in the sight of equity, already members of the *256Union, and it needed no formal ritual or taking of an oath to constitute them such; their uniting with the Union in, the plan to subvert the system of employment at the Hitchman mine, to which they had voluntarily agreed and upon which their employer and their fellow employees were relying, was sufficient.
But the facts render it plain that what the defendants were endeavoring to do at the Hitchman mine and neighboring mines cannot be treated as a bona fide effort to enlarge the membership of the Union. There is no evidence to show, nor can it be inferred, that defendants intended or desired to have the men at these mines join the Union, unless they could organize the mines. Without this, the new members would be added to the number of men competing for jobs in the organized districts, while nonunion men would take their places in the Panhandle mines. Except as a means to the end of compelling the owners of these mines to change their method of operation, the defendants were not seeking to enlarge the union membership.
In any aspect of the matter, it cannot be said that defendants were pursuing their object by lawful means. The question of their intentions — of their bona fides— cannot be ignored. It enters into the question of malice. As Bowen, L. J., justly said, in the Mogul Steamship Case, 23 Q. B. Div. 613, “Intentionally to do that which is calculated in the ordinary course of events to damage, and which does, in fact, damage another in that other person's property or trade, is actionable if done without just causé or excuse.” And the intentional infliction of such damage upon another, without justification or excuse, is malicious in law. Bitterman v. Louisville & Nashville R. R. Co., 207 U. S. 205, 223; Brennan v. United Hatters, 73 N. J. L. 729, 744 et seq., and eases cited. Of course, in a court of equity, when passing upon the right of injunction, damage threatened, irremediable by action at law, is equivalent to damage done. And we cannot deem *257the proffered excuse to be a “just cause or excuse,” where it is based, as in this case, upon an assertion of conflicting rights that are sought to be attained by unfair methods, and for the very purpose of interfering with plaintiff’s rights, of which defendants have full notice.
Another fundamental error in defendants’ position consists in the assumption that all measures that may be resorted to are lawful if they are “peaceable” — that is, if they stop short of physical violence, or coercion through fear of it. In our opinion, any violation of plaintiff’s legal rights contrived by defendants for the purpose of inflicting damage, or having that as its necessary effect, is as plainly inhibited by the law as if it involved a breach of the peace. A combination to procure concerted breaches of contract by plaintiff’s employees constitutes such a violation. Flaccus v. Smith, 199 Pa. St. 128; 54 L. R. A. 640; South Wales Miners’ Federation v. Glamorgan Coal Co., [1905] A. C. 239, 244, 250, 253; Jonas Glass Co. v. Glass Bottle Blowers Association, 77 N. J. Eq. 219, 223.
The present is not a case of merely withholding from an employer an economic need — as a supply of labor— until he assents to be governed by union regulations. Defendants have no supply of labor of which plaintiff stands in need. By the statement of defendant Lewis himself, made in his formal report to the Indianapolis convention of 1907, out of more than 370,000 coal miners in the States of Pennsylvania, Maryland, Virginia, and West Virginia, less than 80,000 (about 22 per cent.) were members of the Union. Considering the Panhandle separately, doubtless the proportion was even smaller, and the supply of non-union labor ample. There is no reason to doubt that if defendants had been actuated by a genuine desire to increase the membership of the Union without unnecessary injury to the known rights of plaintiff, they would have permitted their proselytes to withdraw from plaintiff’s employ when and as they became *258affiliated with the Union — as their contract of employment required them to do — and that in this event plaintiff would have been able to secure an adequate supply of non-union men to take their places. It was with knowledge of this, and because of it, that defendants, through Hughes as their agent, caused the new members to remain at work in plaintiff’s mine until a sufficient number of men should be persuaded to join so as to bring about a strike and render it difficult if not practically impossible for plaintiff to continue to exercise its undoubted legal and constitutional right to run its mine "non-union.”
It was one thing for plaintiff to find, from time to time, comparatively small numbers of men to take vacant places in a going mine, another and a much more difficult thing to find a complete gang of new men to start up a mine shut down by a strike, when there might be a reasonable apprehension of violence at the hands of the strikers and their sympathizers. The disordered condition of a mining town in time of strike is matter of common knowledge. It was this kind of intimidation, as well as that resulting from the large organized membership of the Union, that defendants sought to exert upon plaintiff, and it renders pertinent what was said by this court in the Gompers Case (221 U. S. 418, 439), immediately following the recognition of the right to form labor unions: "But the very fact that it is lawful to form these bodies, with multitudes of members, means that they have thereby acquired a vast power, in the presence of which the individual may be helpless. This power, when unlawfully used against one, cannot be met, except by his purchasing peace at the cost of submitting to terms which involve the sacrifice of rights protected by the Constitution; or by standing on such rights and appealing to the preventive powers of a court of equity. When such appeal is made it is the duty of government to protect the one against the many as well as the many against the one.”
*259Defendants’ acts cannot be justified by any analogy to competition in trade. They are not competitors of plaintiff; and if they were their conduct exceeds the bounds of fair trade. Certainly, if a competing trader should endeavor to draw custom from his rival, not by offering better or cheaper goods, employing more competent salesmen, or displaying more attractive advertisements, but by persuading the rival’s -clerks to desert him under circumstances rendering it difficult or embarrassing for him to fill their places, any court of equity would grant an injunction to restrain this as unfair competition.
Upon all the facts, we are constrained to hold that the purpose entertained by defendants to bring about a strike at plaintiff’s mine in order to compel plaintiff, through fear of financial loss, to consent to the unionization of the mine as the lesser evil, was an unlawful purpose, and that the methods resorted to by Hughes— the inducing of employees to unite with the Union in an effort to subvert the system of employment at the mine by concerted breaches of the contracts of employment known to be in force there, not to mention misrepresentation, deceptive statements, and threats of pecuniary loss communicated by Hughes to the men — were unlawful and malicious methods, and not to be justified as a fair exercise of the right to increase the membership of the Union.
There can be no question that plaintiff was threatened with danger of an immediate strike as a result of the activities of Hughes. The effect of his arguments and representations is not to be judged from the testimony of those witnesses who rejected his Overtures. Naturally, it was not easy for plaintiff to find men who would testify that they had agreed with Hughes to break their contract with plaintiff. One such did testify. But the true. measure of the extent of his operations and the probability of his carrying them to success, are indicated by his *260declaration to Myers that he had about enough names at the Hitchman to “crack off,” by the statement to McKinley that twenty-four men at the Glendale mine had joined the organization, and sixty at the Hitchman, and by the fact that they actually succeeded in shutting down the Richland about the middle of October. The declaration made concerning the Glendale is corroborated by the evidence of what happened at that mine.
That the damage resulting from a strike would be irremediable at law is too plain for discussion.
Therefore, upon the undisputed facts of the case, and the indubitable inferences from them, plaintiff is entitled to relief by injunction. Having become convinced by three costly strikes, occurring within a period of as many years, of the futility of attempting to operate under a closed-shop agreement with the Union, it established the mine on a non-union basis, with the unanimous approval of its employees — in fact upon their suggestion — and under a mutual agreement, assented to by every employee, that plaintiff would continue to run its mine non-union and would not recognize the United Mine Workers of America; that if-any man wanted to become a member of that Union he was at liberty to do so, but he could not be a member and remain in plaintiff’s employ. Under that agreement plaintiff ran its mine for a year and more, and, so far as appears, without the slighest disagreement between it and its men, and without any grievance on their part. Thereupon defendants, having full notice of the working agreement between plaintiff and its men, and acting without any agency for those men, but as representatives of an organization of- mine workers in other States, and in order to subject plaintiff to such participation by the Union in the management of the mine as necessarily results from the making of a closed-shop agreement, sent their agent to the mine, who, with full notice of, and for the very purpose of subverting, *261the status arising from plaintiff’s working agreement and subjecting the mine to the Union control, proceeded, without physical violence, indeed, but by persuasion accompanied with threats of a reduction of wages and deceptive statements as to the attitude of the mine management, to induce plaintiff’s employees to join the Union and at the same time to break their agreement with plaintiff by remaining in its employ after joining; and this for the purpose not of enlarging the membership of the Union, but of coercing plaintiff, through a strike or the threat of one, into recognition of the Union.
As against the answering defendants, plaintiff’s right to an injunction is clear; as to the others named as defendants, but not served with process, the decree is erroneous, as already stated.
Respecting the sweep of the injunction, we differ somewhat from the result reached by the District Court.
So far as it restrains — (1) Interfering or attempting to interfere with plaintiff’s employees for the purpose of unionizing plaintiff’s mine without its consent, by representing or causing to be represented to any of plaintiff’s employees, or to any person who might become an employee of plaintiff, that such person will suffer or is likely to suffer some loss or trouble in continuing in or in entering the employment of plaintiff, by reason of plaintiff not recognizing the Union, or because plaintiff runs a nonunion mine; (2) Interfering or attempting to interfere with plaintiff’s employees for the purpose of unionizing the mine without plaintiff’s consent, and in aid of such purpose knowingly and wilfully bringing about the breaking by plaintiff’s employees of contracts of service known at the timé to exist with plaintiff’s present and future employees; (3) Knowingly and wilfully enticing plaintiff’s employees, present or future, to leave plaintiff’s service on the ground that plaintiff does not recognize the United Mine Workers of America or runs a non-union mine, *262etc.; (4) Interfering or attempting to interfere with plaintiff’s employees so as knowingly and wilfully to bring about the breaking by plaintiff’s employees, present and future, of their contracts of service, known to the defendants to exist, and especially from knowingly and wilfully enticing such employees, present or future, to leave plaintiff’s service without plaintiff’s consent; (5) Trespassing on or entering upon the grounds and premises of plaintiff or its mine for the purpose of interfering therewith or hindering or obstructing its business, or with the purpose of compelling or inducing, by tlireats, intimidation, violent or abusive language, or persuasion, any of plaintiff’s employees to refuse or fail to perform their duties as such; and (6) Compelling or inducing or attempting to compel or induce, by- threats, intimidation, or abusive or violent language, any of plaintiff’s employees to leave its service or fail or refuse to perform their, duties as such employees, or compelling or attempting to compel by like means any person desiring to seek employment in plaintiff’s mine and works from so accepting employment therein; — the decree is fully supported by the proofs. But it goes further, and awards an injunction against picketing and against acts of physical violence, and we find no evidence that either of these forms of interference was threatened. The decree should be modified by eliminating picketing and physical violence from the sweep of the injunction, but without prejudice to plaintiff’s right, to obtain an injunction hereafter against these forms of interference if proof shall be produced, either in proceed-, ifigs supplemental to this action or in an independent action, that such an injunction is needed.
The decree of the Circuit Court of Appeals is reversed, and the decree of the District Court is modified as above stated, and as so modified it ^s affirmed, and the cause is remanded to the District Court for further proceedings in conformity with this opinion.
Mr. Pickett was superintendent of the Hitchman and Glendale mines, and it was with him that the miners made their agreements to refrain from membership in the Union; Daugherty and Jarrett were miners at the Hitchman, and had been,- respectively, President a,nd Financial Secretary of the local union at the time of the 1906 strike, when the local deserted the U. M. W. A.