Mr. Justice Roberts

delivered the opinion of the Court,

The Circuit Court of Appeals refused1 to decree enforcement of an order of the National Labor Relations Board.2 We granted certiorari because of an asserted conflict of decision.3

The respondent, a California corporation, is engaged in the transmission and receipt of telegraph, radio, cable, and other messages between points in California and points in other States and foreign, countries. It maintains an office in San Francisco for the' transaction of its business wherein it employs upwards of sixty supervisors, operators and clerks, many of whom are members- oLLocal No. 3 of the American Radio Telegraphists Association, a national labor organization; the membership of the local comprising “point-to-point” or land operators employed by respondent at San Francisco. Affiliated with the national organization also were locals whose members are exclusively marine operators who work upon oceangoing vessels. The respondent, at its San Francisco office, dealt with committees of Local No. 3; and its parent company, whose headquarters were in New York, dealt with representatives of the national organization. Demand was made by the latter for the execution of agreements respecting terms and conditions of employment *337of marine and point-to-point operators. On several occasions when representatives of the union conferred with officers of the respondent and its parent company the latter requested postponement of discussion of the proposed agreements and the union acceded to the requests. In September 1935 the union pressed for immediate execution of agreements and took the position that no contract would be concluded by the one class of operators unless an agreement were simultaneously made with, the other. Local No. 3 sent a representative to New York to be in touch with the negotiations and he kept its. officers advised as to what there, occurred. The local adopted a resolution to the effect that if satisfactory terms were not obtained by September 23 a strike- of the San Francisco point-to-point operators should be called. The national officers determined on-a general strike in view of the unsatisfactory state of the negotiations. This fact was communicated to Local No. 3 by,its representative in.New York and .the local officers called out the employes of the San Francisco office. -At midnight Friday, October 4, 1935, all the men there employed went on strike. The respondent, in order to maintain service, brought employes from its Los Angeles office and others from the New York and Chicago offices, of the parent company to fill the strikers’ places.

Although none of the San Francisco strikers returned to work-Saturday; Sunday, or Monday, the strike proved unsuccessful in other parts of the country and, by Monday evening, October 7th, a number of the men became convinced that it would fail and that they had better return to work before their places were filled with new employes. One of them telephoned the respondent’s traffic supervisor Monday evening to inquire whether the men'might return. He was told that the respondent would take them back and it was arranged that the official should meet the employes. at a downtown hotel and make a statement to *338them. Before leaving the company’s office for this purpose, the supervisor consulted with his superior, who told him that' the men might return to work in their former positions but that, as the company had promised eleven men brought to San Francisco they might remain if they so desired, the supervisor would have to handle the return of the striking employes in such fashion as not to displace any of the new men who desired to continue in San Francisco. A little later the supervisor met two. of "the striking employes and gave them a list of all the strikers, together with their addresses, and the telephone numbers of those who had telephones, and it was arranged that these two employes should telephone the strikers to come to a meeting at the. Hotel Bellevue in the early hours of Tuesday, October 8th. - In'furnishing this list the supervisor stated that the men could return, to work in a body but he checked off the names of eleven strikers who he’ said would have to file applications for reinstatement, which applications would be subject to the approval of an executive of the company in New York. Because of this statement the two employes, in notifying the strikers of the proposed ..meeting, with the knowledge of the supervisor, omitted to communicate with the eleven men whose names had been checked off. Thirty-six men attended .the meeting. Some of the eleven in question heard of it and attended. The supervisor appeared at the meeting and reiterated his statement that the men could go back to work at once, but read from a list the names of the eleven who would be -required to file applications for reinstatement to be passed 'upon in New York. Those present at the meeting voted on the question of immediately returning to work, and the proposition was carried. Most of the men left the meeting and went to the respondent’s office Tuesday morning, October 8th, where on that day they resumed their usual duties. Then or shortly thereafter, six of the eleven in question took their places and resumed *339their work without challenge. It turned out that only five of the new then brought to San Franciscp desired to stay. -

Five ^strikers who were prominent in the activities of the union and in connection with the strike, whose names appeared upon the list of eleven, reported at the bfifep at various times between Tuesday and Thursday. EaclLof them was told that he would have to fill out an application for employment; that the roll of. employes was complete, and that his application would be considered in connection with any vacancy that might thereafter occur. These men not having been reinstated in the course of three weeks, the secretary of Local No. 3 presented a charge to the National Labor Relations Board.that the respondent had violated § 8 (1) and (3) of the National Labor Relations Act.4 Thereupon the Board'filed a complaint ..charging that the respondent had discharged, and was refusing to employ, the five men who had not been reinstated to their positions, for the- reason that they had joined and assisted the labor organization known as Local No. 3 and had engaged in concerted activities with other employes of the respondent, for the purpose of collective bargaining and other mutual aid and protection; that by such discharge respondent had interfered with, restrained, and coerced the employes in the exercise of their rights guaranteed by § 75 of the National Labor Relations Act and so had been guilty of an unfair labor practice within the meaning of 1 8 (1) of the Act. The complaint further alleged that the discharge of these men was a discrimination in respect of their hire and tenure of employment and a discouragement of membership in Local No. 3, and thus an unfair labor practice within the meaning of § 8 (3) of the Act.

*340. The respondent filed an answer denying the allegations of the complaint, and moved to dismiss the proceeding on the, ground that the Act is unconstitutional. The motion was taken under advisement by the Board’s examiner and the case proceeded to hearing. After the completion of its testimony, the Board filed an amended complaint to comport witfr the evidence, in which it charged that the respondent had refused to re-employ the five operators for the reason that they had joined and assisted the labor organization known as Local No. 3 and engaged with other employes in concerted activities for the purpose of collective bargaining and other mutual aid and protection; that the refusal to re-employ them restrained and coerced the employes in the exercise of rights guaranteed by § 7 and so constituted an unfair labor practice within § 8 (1) of the Act. The amended complaint further asserted that-the refusal to re-employ the men discriminated in regard to their hire and tenure of employment , and discouraged membership in Local No. 3 and thus amounted to an unfair labor practice under § 8 (3) of the Act. The respondent entered a general denial to the amended complaint and presented its evidence. At the conclusion of the testimony, the Board transferred the cause for further hearing before the members of the Board at Washington, and after oral argument and the filing of a brief, made its findings of fact.

The subsidiary or evidentiary facts were found in great detail and, upon the footing of them, the Board reached conclusions of fact to the effect that Local No. 3 is a labor organization within the meaning of the Act; that “by refusing to reinstate to employment” the five men in question, “thereby discharging said employes,” the respondent by “each of said discharges,” discriminated in regard to tenure of employment and thereby discouraged membership in the labor organization known as Local No. 3, and, by the described acts “has interfered with rtestraiped *341and coerced its employes in the exercise of the rights guaranteed by Section 7 of the National Labor Relations Act.” As conclusions of law the Board found that the respondent had engagéd in unfair labor practices affecting commerce within the meaning of § 8, subsections (L) and (3), and § 2, subsections (6) and (7)6 of the Act. It entered an order that respondent cease and desist from discharging, or threatening to discharge, any of its employes for the reason that they had joined or assisted Local No: 3 or otherwise engaged in union activities; from interfering with, restraining or coercing its employes in the exercise of the rights guaranteed by § 7 of the Act; offer the five men immediate and full reinstatement to their former positions, without prejudice to rights and privileges previously enjoyed, and make each of them whole for any loss of wages due to their discharge; post notices that the respondent would not discharge or dis-. criminate against members of, or those desiring to become members of, the union, and keep the notices posted for thirty days.

As permitted by the Act, the Board filed in the Circuit Court of Appeals a transcript of the record of its proceeding, and a petition for enforcement of its order. In its answer the respondent denied the jurisdiction of the court on the ground that the Act violated Article III, and the Fifth, Seventh, and Tenth Amendments, of the Constitution; that the order amounted to an abuse of discretion because arbitrary and capricious, and was not supported by the evidence; that the trial examiner erred in his rulings on evidence; that the Board erred in overruling exceptions to his rulings, and that the Board’s findings of fact and conclusions of law were erroneous.

Upon the hearing before the Circuit Court of Appeals, one judge held that the action of the Board was within *342the power sought to be conferred upon it by the statute but that the grant of .power violated the due process clause of the Fifth Amendment, and the award of back pay to- the employes, without a jury trial, violated thSeventh Amendment. Another judge held that as the statute defined employes to include a person whose work had ceased “as a consequence of, or in connection with, any current labor dispute,” and since there was no allegation, evidence, or finding as to such a dispute, the strikers had ceased to be employes within the meaning of the Act and the respondent’s treatment of them could not. violate the Act. One judge dissented,-holding, that the Board’s order was within its statutory authority and did not violate the Constitution. A petition and supplemental petition for rehearing were granted and,'.after argument, the court reaffirmed its former decision. The judge who had previously declared the Board’s action within the terms of the statute, but unconstitutional, con- • strued the Act as not intended to work the unconstitutional result of compelling an employer to enter into a contract of employment agajnst his will and, hence, as requiring only that the strikers be reinstated to the position of applicants for employment -rather than employes. The other judges adhered to the views they had previously expressed.

The petitioner contends the court erred in holding that men who struck,because of a failure of negotiations concerning wages and terms of employment ceased tq> be employes within,the meaning of the statute; erred in not holding it an unfair labor practice, forbidden by the statute, for an employer to. discriminate because of''union activities in the reinstatement of men who have gone on strike because of a failure of negotiations concerning wages and terms of employment; erred in failing to hold that the Act authorizes the Board to order reinstatement of persons thus, discriminated against; and one of the.. *343judges erred in holding that the Act, if construed to authorize the Board to require such reinstatement, violates the Fifth Amendment.

On the other hand, the respondent insists that it was not accorded due process of law, because the unfair labor practice charged in the original complaint was abandoned and the action of the Board was based upon a conclusion of fact not within the issues, presented; that there is no basis for the Board’s order,- Pecáuse there is no finding that the strikers ceased work as a consequence of, or in connection with, any labor dispute, as defined in the statute; that the Act does not empower the Board to compel an employer to re-employ dr reinstate those who have abandoned negotiations and gone on strike prior to any unfair labor practice, where the employer, after the strike is effective, and before committing any unfair labor practice, has permanently .employed: others in place of the strikers; that, if the Act be held to authorize the Board’s order, it violates the Fifth Amendment; that Article III of the Constitution requires that the court render its independent judgment upon the- quasi-jurisdictional facts upon which the Board’s order was based; that the Board’s order was, in the light of the facts, so arbitrary and capricious as to warrant the court’s refusal to enforce it;' and that the case is not properly before us because certiorari was not sought within the time fixed by law.

We hold that we have jurisdiction; that the Board’s order is within its competence and does not contravene any provision of the Constitution.

First. Within the thirty days prescribed by the rules of the Circuit Court of Appeals the petitioner moved for a rehearing and for leave, if deemed appropriate, to take further evidence and add the same to the record before the Board.- While this application was pending a supplemental petition for rehearing was presented. During the term the court-entertained both petitions and granted a re*344hearing and, after oral argument and submission of briefs, wrote further opinions based upon the petitions for rehearing. We think the court had not lost jurisdiction of the cause; that its final judgment was the order entered upon the petitions for rehearing; and that the three months within which the petitioner must apply for certiorari ran from the date of the order dismissing the petition for rehearing and confirming the original order.

Second. Under the findings the strike was a consequence of, or in connection with, a current labor dispute as defined in § 2 (9) of the Act. That there were pending negotitions for the execution of a contract touching wages and terms and conditions of employment of point-to-point operators cannot be denied. But it is said the record fails to disclose what caused these negotiations to fail or to show that the respondent was in any wise in fault in failing to-comply, with the union’s demands; and, therefore,for all that appears, the strike was not called by reason of fault of the respondent. The argument confuses a current labor dispute with an unfair labor practice defined .in § 8 of the Act. True there is no evidence that respondent had been guilty of any unfair labor practice prior to the strike, but within the intent of the Act there was an existing labor dispute in connection with which the strike was called. The finding is that the strike was deemed “advisable in view of the unsatisfactory state of the negotiations” in New York. It was unnecessary for the Board to find what was in fact the state of the negotiations in New York when the strike was called, or in so many words that a labor dispute as defined by the Act existed. The wisdom or unwisdom of the men, their justification or lack of it, in attributing to respondent an unreasonable or arbitrary attitude in connection with the negotiations, cannot determine whether, when they struck, they did so< as a consequence of or in connection with a current- labor dispute.

*345 Third. The strikers remained employes under § 2 (3) of the Act which provides: “The term ‘employee’ shall, include ... any individual whose work has ceased as a consequence of, or in connection with, any current labor dispute of because of any unfair labor practice, and who has not obtained any other regular and substantially equivalent employment;..Within this definition the strikers remained employes for the purpose of the Act. and were protected against the unfair labor practices denounced by it. ,

Fourth. It is contended that the Board lacked jurisdiction becáuse respondent was at nó time guilty of any unfair labor practice. Section 8 of the. Act denominates as such practice action by . an employer to interfere with, restrain,,or coerce employes in the exercise of their rights to organize, to form, join or assist labor organizations, and to engage in concerted activities for the purpose of collective bargaining or other mutual aid or protection, or “by discrimination in regard to . . . tenure of employment or any term or condition of employment to encourage or ,discouragé membership in any labor organization: . ...” There is no evidence and .no finding thát the respondent was guilty of any unfair labor practice in connection with the negotiations in New York. On the contfary, it affirmatively appears that the respondent was negotiating with the authorized representatives of the union. Nor was it an unfair labor practice to replace the striking employes with others in an effort, to carry on the business. Although § 13 provides, “Nothing in this Act shall be construed so as to interfere with or impede or diminish in any way the right ‘to strike,” it does not follow that an employer, guilty of no act denounced by the statute, has lost the right to protect and continue his business by supplying places left vacant by strikers. And he is not bound to discharge those hired to fill the places of strikers, upon the election of the latter to resume- their employ*346ment, in order to create places for them.7 The assurance by respondent to those who accepted employment during the strike that if they so desired their places might be permanent was not' an unfair labor practice nor was it such to reinstate only so many of the strikers as there were vacant places to be filled. But the claim put for-" ward is that the Unfair labor practice indulged by the respondent was discrimination in reinstating striking employes by keeping out certain of them for the sole reason that they had been active in the union. As we have said, the strikers retainéd, under the Act, the status of employes. Any such discrimination in putting them back to work is, therefore, prohibited by § 8.

Fifth. The Board’s findings ¿s to discrimination are supported by evidence. We shall not attempt a discussion of the conflicting claims as to the proper conclusions to be drawn from the testimony. There was, evidence, which the Board credited, that several of the five men in question were told that their union activities made them undesirable to their employer; and'that some of them did not return to work with the great body of the men at 6'"o’clock on Tuesday morning because they understood they would not bé allowed to go to work until the superior officials had passed upon their applications. When they did apply at rimes between Tuesday morning and Thursday they were each told that the quota was full and that ■their applications could not be granted in any event until a vacancy occurred; This was on the ground that five of the eleven new men remained at work in San Francisco. On the other hand, six of the. eleven strikers listed for separate treatment who reported for work early Tuesday morning, or within the next day or so, were permitted to go back to work and were not compelled to await the approval of their applications. It appears that all of the *347men who had been on strike signed applications for reemployment shortly after their resumption of work. The Board found, and we cannot say that its finding is unsupported, that, in taking back six of the eleven inen and excluding five who were active union men; the respondent’s officials discriminated against the latter on account of their union activities and that the excuse given that they did not apply until after the quota was full was an afterthought and not the true reason for the discrimination against them.

As we have said, the respondent was not bound to disr place men hired to take the strikers’ places in order to provide positions for them. It' might have refused reinstatement on the ground of skill or ability', but the Board found that it did not do so. It might have resorted, to any one of a number of methods of determining which of its striking employes would have to wait because five men had taken permanent positions during , the strike, but it is found that the preparation and use of the list, and the action taken by respondent, were with the purpose- to discriminate against those most active in the union. There is evidence to support these findings.

Sixth. The Board’s order does not violate the Fifth Amendment. The respondent insists that the relation of employer and employe ceased at the inception of the strike. The plain meaning of the Act is that if men strike in connection with a current labor dispute their action is not to be construed as a renunciation of the employment relation and they remain employes for the remedial purposes specified in the Act. We have held that, in the.-exercise of the commerce power, Congress may impose upon contractual relationships reasonable regulations calculated to protect commerce against threatened industrial strife. National Labor Relations Board v. Jones & Laughlin Steel Corp., 301 U. S. 1, 48. The Board’s order there sustained required the reinstatement of discharged employes. The *348requirement interfered with freedom of contract which the employer would have enjoyed except for the mandate of the statute. The provision of the Act continuing the relationship of employer and employe in the case of a strike as a consequence of, or in connection with, a current labor dispute, is a regulation of the same sort and within the principle of our decisión.

Seventh. The affirmative relief ordered by the Board was within its. powers and its order was not arbitrary or capricious.

As we have held in National Labor Relations Board v. Pennsylvania Greyhound Lines, 303 U. S. 261, the relief which the statute empowers the Board to grant is to be adapted to the situation which calls for redress. Op the basis of the findings, five men who took part in the strike were discriminated against in connection with a blanket offer to reinstate striking employes. The Board enjoined further discrimination against employes by reason of union' affiliation, but it could not grant complete relief in respect of the five men 'short of ordering that the discrimination be neutralized by their being given their former positions and reimbursed for the loss due. to their lack of employment consequent upon the respondent’s discrimination. The order is criticized as arbitrary in that.it is said to award back pay to date of reinstatement with deductions, only for what was earned to the date of the order. We do not sopead it, and the Board admits that credit must be given for all sums earned to date of reinstatement, and so construes the- order. It is further said that the order arbitrarily and unreasonably requires the notices to be posted to state that respondent will not discharge its reinstated employes for. any reason whatever. This clause of the order is. inartificially drawn, and counsel for the Board admit that it .should be read in connection with the remainder of the order forbidding discharge on the ground of unipn activity.

*349 Eighth. The respondent was not denied a hearing, with respect to the offense found by the Board. The respondent says that it was summoned to answer a complaint that it discriminated by discharging the five men and.-that, after all the evidence was in, this complaint was withdrawn and a new one presented asserting that its refusal to re-employ the five men was the head and front of its offending. Then it is said that when the Board came to make its finding it reverted to the position that what the respondent did had not been a failure to employ but a wrongful discharge. Thus the respondent claims that it is found guilty of an unfair labor practice which was not within the issues upon which the case was tried. The position is highly technical.. All parties to the proceeding knew from the outset that the thing complained of was discrimination against certain men by reason of their alleged union activities. If there was a current labor dispute the men were* still employes by virtue of § 2 (3), and the refusal to let them work was a discharge. The respondent says that as the Board failed to find, in so many words, that there was a current labor dispute, its conclusion pf fact that the men were discharged has no basis. But the' Board found that the strike was called because the strikers were informed that the, negotiations for a working agreement in New York were not proceeding satisfactorily. We think its action cannot be overturned for the mere reason that it failed to characterize the situation as a current labor dispute.- The respondent, further urges that, when the amended complaint was filed and the original one withdrawn, the charge it had to meet was a refusal to re-employ; that the phrase “re-employ’ means “employ anew”; that if the Board had found a •failure to employ the five men because of discrimination forbidden by the Act, the findings would have followed the complaint, whereas the Board, in its conclusions of fact, referred to respondent’s action as “refusal to reinstate to ■ *350employment” and as á discharge; and the argument is that the findings do not follow''the pleadings.

A review of the record shows that at no time during the hearings was there any misunderstanding as to what was the basis of the Board’s complaint. The entire evidence, pro and con, was directed to the question whether, when the strike failed and the men desired to come back and were' told that the strike would be forgotten and that they might come back in a body save for eleven men who were singled out for different treatment, six of whom, however, were treated like everyone else, the respondent did in fact discriminate against the remaining five because of union activity. While the respondent was entitled to know the basis of the complaint against it, and to explain its conduct, in an effort to meet that complaint, we find from the record that it understood the issue and was afforded full opportunity to justify the action of its officers as innocent rather than discriminatory.

At the conclusion of the testimony, and prior to oral argument before the examiner, the Board transferred the proceeding to Washington to be further heard before the Board. It denied respondent’s motion to resubmit the cause to the' trial examiner with directions to prepare and file an intermediate report. In the Circuit Court of Appeals the respondent assigned error to this ruling. It appears that oral argument was had and a brief was filed with the Board after which it made its findings of fact and conclusions of law. The respondent now asserts that the failure of the Board to follow its usual practice of the submission of a tentative report by the trial examiner and a hearing on exceptions to that report deprived the respondent of opportunity to call to the Board’s attention the alleged-iatal variance between thé allegations of the complaint and the Board’s findings. What we have said sufficiently-indicates that, the issues and contentions of *351the parties were clearly defined and as no other detriment or disadvantage is claimed to have ensued from the Board’s procedure the matter is not one calling for a reversal of the order. The Fifth Amendment guarantees no particular form of procedure; it protects substantial rights. Compare Morgan v. United States, 298 U. S. 468, 478. The contention that the respondent was denied a full and adequate hearing must be rejected.

Ninth. The other contentions of the respondent are overruled because foreclosed by earlier decisions of this court. .

The judgment of the Circuit Court of Appeals is reversed and the causé is remanded to that court for further proceedings in conformity with this opinion.

Reversed.

Mr. Justice Cardozo and Mr. Justice Reed took no part in the consideration or decision of this case.

Mr. Justice White

delivered the opinion of the Court.

Thé question before us is whether an employer commits an unfair labor practice under § 8 (a) 1 of the *222National Labor Relations Act, 61 Stat. 136, 29 U. S. C. § 158' when he extends a 20-year seniority credit to strike replacements and strikers who leave the strike and return to work. The Court of Appeals for the Third Circuit in this case joined the Ninth Circuit, Labor Board v. Potlatch Forests, Inc., 189 F. 2d 82 (and see Labor Board v. Lewin-Mathes, 285 F. 2d 329, from the Seventh Circuit), to hold that such super-seniority awards are not unlawful absent a showing of an illegal motive on the part of the employer. 303 F. 2d 359. The Sixth Circuit, Swarco, Inc., v. Labor Board, 303 F. 2d 668, and the National Labor Relations Board are of the opinion that such conduct can be unlawful even when the employer asserts that these additional benefits are necessary to continue his operations during a strike. To resolve these conflicting views upon an important question in the administration of the National Labor Relations Act, we brought the case here. 371 U. S. 810.

Erie Resistor Corporation and Local 613 of the Inter-, national Union of Electrical, Radio and Machine Workers were bound by a collective bargaining agreement which was due to expire on March 31, 1959. In January 1959, both parties met to negotiate new terms but, after extensive bargaining, they were unable to reach agreement. Upon expiration of the contract, the union-, in support of its contract demands, called a strike which was joined by all of the 478 employees in the unit.2

The company, under intense competition and subject to insistent demands from its customers to maintain deliv*223eries, decided to continue production operations. Transferring clerks, engineers and other nonunit employees to production jobs, the company managed to keep production at about 15% to 30% of normal during the month of April. . On May 3, however, the company notified the union members that it intended to begin hiring replacements and that strikers would retain their jobs until replaced. The plant was located in an area classified by the United States Department of Labor as one of severe unemployment and the company had in fact received applications for .employment as early as a week or two after the strike began.

Replacements were to.ld that they would not be laid off or discharged at the end of the strike. To implement that assurance, particularly in view of the 450 employees already laid off on March 31, the company .notified the union that it intended to accord the replacements some form of super-seniority. At regular bargaining sessions between the company and union,, the union made it clear that, in its view, no matter what form the super-seniority plan might take, it would necessarily work an illegal discrimination against the strikers. As negotiations •advanced on other issues, it became evident that super-seniority was fast becoming the focal point of disagreement. On May 28, the company informed the union that it had decided to award 20 years’3 additional seniority both to replacements and to strikers who returned to work, which would be available only for credit against future layoffs and which could not be used for other employee benefits based on years of service. The strikers, at a union meeting the next day, unanimously resolved to continue striking now in protest against the proposed plan as well.

*224The company made its first official announcement of the super-seniority plan on June 10, and by June 14, 34 new employees, 47 employees recalled from layoff status and 23 returning strikers had accepted production jobs. The union, now under great pressure, offered to give up some of its contract demands if the company would abandon super-seniority or go to arbitration on the question, but the company refused. In the following week, 64 strikers returned to work and 21 replacements took jobs, bringing the total to 102- replacements and recalled workers and 87 returned strikers. When the number of returning strikers went up to 125 during the following week, the union capitulated. A new labor agreement on the remaining economic issues was executed on July 17, and an accompanying settlement agreement was signed providing that the company’s replacement and job assurance policy should be resolved by the National Labor Relations Board and the federal courts but was to remain in effect pending final disposition.

Following the strike’s termination, the company reinstated those strikers whose jobs had not been filled (all but 129 were returned to their jobs). At about the same time,' the union received some 173 resignations from membership. By September of 1959, the production unit work force had reached a high of 442 employees, but by May of 1960, the work force had gradually slipped back to 240. Many employees laid off during this cutback period were reinstated strikers whose seniority was insufficient to retain their jobs as a consequence of the company’s super-seniority policy.

The union filed a charge with the National Labor Relations Board alleging.that awarding super-seniority during the course of the strike constituted an unfair labor practice and that the subsequent layoff of the recalled strikers pursuant to such a plan was unlawful. The Trial Examiner found that the policy was promulgated for legitimate *225economic reasons;4 not for illegal or discriminatory purposes, and recommended that the union’s complaint be dismissed. The Board could not agree with the Trial Examiner’s conclusion that specific evidence of subjective intent to discriminate against the union was necessary to finding that super-seniority granted during a strike is an unfair labor practice. Its consistent view, the Board said, had always been that super-seniority, in circumstances such as these, was an unfair labor practice. The Board rejected the argument that super-seniority granted during a strike is a legitimate corollary of the employer’s right of replacement under Labor Board v. Mackay Radio & Tel. Co., 304 U. S. 333, and detailed at some length the factors which to it indicated that “superseniority is a form of discrimination extending far beyond the employer’s right of replacement sanctioned by Mackay, and is, moreover, in- direct conflict with the express provisions of the Act prohibiting discrimination.” Having put aside Mackay, the Board went on to deny “that specific evidence of Respondent’s discriminatory motivation is required to establish the alleged violations of the Act,” relying upon Radio Officers v. Labor Board, 347 U. S. 17, Republic Aviation Corp. v. Labor Board, 324 U. S. 793, and Teamsters Local v. Labor Board, 365 U. S. 667. Moreover, in the Board’s judgment, the employer’s insistence that its overriding purpose in granting super-seniority was to keep its plant open and *226that business necessity justified its conduct was unacceptable since “to excuse such conduct would greatly diminish, if not déstroy, the right to strike guaranteed by the Act, and would run directly counter to. the guarantees of Sections 8 (a)(1) and (3) that employees shall not be discriminated against for engaging in protected concerted activities.” 5 Accordingly, the Board declined , to make findings as to the specific motivation of the plan or its business necessity in the circumstances here'.

The Court of Appeals rejected as unsupportable the rationale of the Board that a preferential seniority policy is illegal however motivated.

“We are of the opinion that inherent in the right of an employer to replace strikers during a strike is the concomitant right to adopt a preferential seniority policy which will assure the replacements some form of tenure, provided the policy is adopted Solely to protect and continue the business of the employer. We find nothing in the Act which proscribes such a policy. Whether the policy adopted by the Company in the instant case was illegally motivated we do not decide. The question is one of fact for decision by the Board.” 303 F. 2d, at 364.

It consequently denied the Board’s petition for enforcement and remanded the case for further findings.

*227We think the Court of Appeals erred in holding that, in the absence of a finding of specific illegal intent, a legitimate business purpose is always' a defense to an unfair labor practice charge. Cases in- this Court dealing with unfair labor practices have recognized the relevance and importance of showing the employer’s intent or motive to discriminate or to interfere with union rights. But specific evidence of such subjective intent is “not an indispensable element of proof of violation.” Radio Officers v. Labor Board, 347 U. S. 17, 44. “Some conduct may by its very nature contain the implications of the required intent; the natural foreseeable consequences of certain action may warrant the inference. . . . The existence of discrimination may at times be inferred by the Board, for ‘it is permissible to draw on experience in factual inquiries.’ ” Teamsters Local v. Labor Board, 365 U. S. 667, 675.

Though the intent necessary for an unfair labor practice may be shown in different ways, proving it in one manner may have far different weight and far different consequences than proving it in another. When specific evidence of a subjective intent to discriminate or to encourage or discourage union membership is shown, and found, many otherwise innocent or ambiguous • actions which are normally incident to the conduct of a’business may, without more, be converted into unfair labor practices. Labor Board v. Jones & Laughlin Steel Corp., 301 U. S. 1, 46 (discharging employees); Associated Press v. Labor Board, 301 U. S. 103, 132 (discharging employees); Phelps Dodge Corp. v. Labor Board, 313 U. S. 177 (hiring employees). Compare Labor Board v. Brown-Dunkin Co., 287 F. 2d 17, with Labor Board v. Houston Chronicle Publishing Co., 211 F. 2d 848 (subcontracting union work); and Fiss Corp., 43 N. L. R. B. 125, with Jacob H. Klotz, 13 N. L. R. B. 746 (movement of plant to another town). Such proof itself is normally sufficient to destroy the em*228ployer’s claim of a legitimate business purpose, if one is made, and provides strong support to a finding that there is interference with union rights or that union membership will be discouraged. Conduct which on its face appears to serve legitimate business ends in these cases is wholly impeached by the showing of an intent to encroach upon protected rights. The employer’s claim of legitimacy is totally dispelled.6

The outcome may well be the same when intent is founded upon the inherently discriminatory or destructive nature of the conduct itself. The employer in such cases must be held to intend the very consequences which fore-seeably and inescapably flow from his actions and if he fails to explain away, to justify or to characterize his actions as something different than they appear on their face, an unfair labor practice charge is made out. Radio Officers v. Labor Board, supra. But, as often happens, the employer may counter by claiming that his actions were taken in the pursuit of legitimate business ends and that his dominant purpose was not to discriminate or to invade union rights but to accomplish business objectives acceptable under the Act. Nevertheless, his conduct does speak for itself — it is discriminatory and it does discourage union membership and whatever the claimed overriding justification may be, it carries with it unavoidable consequences which the employer not only foresaw but which he must have intended. . As is not uncommon in human experience, such situations present a complex of motives and preferring one motive to another *229is in reality the far more delicate task, reflected in part in decisions of this Court,7 of weighing the interests of employees in concerted activity against the interest of the employer in. operating his business in a particular manner and of balancing in the light of the Act and its policy the intended consequences upon employee rights against the business ends to be served by the employer’s conduct.8 *230This essentially is the teaching of the Court’s prior cases dealing with this problem and, in our view, the Board did not depart from it.

The Board made a detailed assessment of super-seniority and, to its experienced eye, such a plan had the following characteristics:

(1) Super-seniority affects the tenure of all strikers whereas permanent replacement, proper under Mackay, affects only those who are, in actuality, replaced. It is one thing to say that a striker is subject to loss of his job at the strike’s end but quite another to hold that in addition to the threat of replacement, all strikers will at best return to their jobs with seniority inferior to that of the replacements and of those who left the strike.

(2) A super-seniority award necessarily operates to the detriment of those who participated in the strike as compared to nonstrikers.

(3) Super-seniority made available to striking bargaining unit employees as well as to new employees is in effect offering individual benefits to the strikers to induce them to abandon the strike.

(4) Extending the benefits of super-seniority to striking bargaining unit employees as well as to new replacements deals a crippling blow to the strike effort. At one stroke, those with low seniority have the opportunity to obtain the job security which ordinarily only long years of service can bring, while conversely, the accumulated’ seniority of older employees is seriously diluted. This combination of threat and promise couM be expected to undermine the strikers’ mutual interest and place *231the entire strike effort in. jeopardy. The history of this strike and its virtual collapse following the announcement of the plan emphasize the grave repercussions of super-seniority.

(5) Super-seniority renders future bargaining difficult, if not impossible, for the.collective bargaining representative. Unlike the replacement granted in Mackay which ceases to be an issue once the strike is over, the plan here creates a cleavage in the plant continuing long after the strike is ended. Employees are henceforth divided into two camps: those who stayed with the union and those who returned before the end of the strike and thereby gained extra seniority. This breach is re-emphasized with each subsequent layoff and stands as an ever-present reminder of the dangers connected with striking and with union activities in general.

In the light of this analysis, super-seniority by its very terms operates to discriminate between strikers and non-strikers, both during and after a strike, and its destructive impact upon the strike and union activity cannot be doubted. The origin of the plan, as respondent insists, may have been to keep production going and it may have been necessary to offer super-seniority to attract replacements and induce union members to leave the strike. But if this is true, accomplishment of respondent’s business purpose inexorably was contingent upon attracting sufficient replacements and strikers by offering preferential inducements to those who worked as opposed to those who struck: We think the Board was entitled to treat this case as involving conduct which carried its own indicia of intent and which is barred by the Act unless saved from illegality by an overriding business purpose justifying the invasion of union rights. The Board concluded that the business purpose asserted was insufficient to insulate *232the super-seniority plan from the reach of §8 (a)(1) and § 8 (a)(3), and we turn now to a review of that conclusion.

The Court of Appeals and respondent rely upon Mac-kay as precluding the result reached by the Board but we are not persuaded. .Under the decision in that case an employer may operate his plant during a strike and at its conclusion need not discharge those who worked during the strike in order to make way for returning strikers. It may be, as the Court of Appeals said, that “such a replacement policy is obviously discriminatory and may tend to discourage union membership.” But Mackay did not deal with super-seniority, with its effects upon all strikers, whether replaced or not, or with its powerful impact upon a strike itself. Because the employer’s interest must be deemed to outweigh the damage to concerted activities caused by permanently replacing strikers does not mean it also outweighs the far greater • encroachment resulting from super-seniority in addition to permanent replacement.

We have no intention of questioning the continuing vitality of the Mackay rule, but we are not prepared to extend it to the situation we have here. To do so would require us to set aside the Board’s considered judgment that the Act and its underlying policy require, in the present context, giving more weight to the harm wrought by super-seniority than to the interest of the employer in operating its plant during the strike by utilizing this particular means of attracting replacements. We find nothing in the Act or its legislative history to indicate that super-seniority is necessarily an acceptable method of resisting the économic impact of a strike, nor do we find anything inconsistent with the result which the Board reached. On the contrary, these sources are wholly consistent with, and lend full support to, the conclusion of the Board.

*233Section 7 9 guarantees, and §8 (a)(1) protects from employer interference the rights of employees to engage in concerted activities, which, as Congress has indicated, H. R. Rep. No. 245, 80th Cong., 1st Sess. 26, include the right to strike.- Under § 8 (a)(3), it is unlawful for an employer by discrimination in terms of employment to discourage “membership in any labor organization,” which includes discouraging participation in concerted activities, Radio Officers v. Labor Board, 347 U. S. 17, 39-40, such as a legitimate strike. Labor Board v. Wheeling Pipe Line, Inc., 229 F. 2d 391; Republic Steel Corp. v. Labor Board, 114 F. 2d 820. Section 1310 makes clear that although the strike weapon is not an unqualified right, nothing in the Act except as specifically provided is to be construed to interfere with this means of redress, H. R. Conf. Rep. No. 510, 80th Cong., 1st Sess. 59, and § 2 (3) 11 pieserves to strikers their unfilled positions and status as employees during the pendency of a strike. S. Rep. No. 573, 74th Cong., 1st Sess. 6.12 This repeated solicitude for *234the right to strike is predicated upon the conclusion that a strike when legitimately employed is . an economic weapon which in great measure implements and supports the principles of the collective bargaining system.13

While Congress has from .time to time revamped and redirected national labor policy, its concern for the integrity of the strike weapon has remained constant. Thus when Congress chose to qualify the use of the strike, it did so by prescribing the limits and conditions of the abridgment in exacting detail, e. g., §§ 8 (b)(4), 8 (d), by indicating the precise procedures to be followed in effecting the interference, e. g., § 10 (j), (k), (1); §§ 206-210, Labor Management Relations Act, and by preserving the positive command of § 13 that the right to strike is to be given a *235generous interpretation within the scope of the labor Act. The courts have likewise repeatedly recognized and effectuated the strong interest of federal labor policy in the legitimate use of the strike. Automobile Workers v. O’Brien, 339 U. S. 454; Amalgamated Assn. of Elec. Ry. Employees v. Wisconsin Employment Rel. Bd., 340 U. S. 383; Labor Board v. Remington Rand, Inc., 130 P. 2d 919; Gusano v. Labor Board, 190 F. 2d 898; cf. Sinclair Ref. Co. v. Atkinson, 370 U. S. 195.

Accordingly, in view of the deference paid the strike weapon by the federal labor laws and the devastating consequences upon it which the Board found was and would be precipitated by respondent’s inherently discriminatory super-seniority plan, we cannot say the Board erred *236in the balance which it struck here. Although the Board’s decisions are by no means immune from attack in the courts as cases in this Court amply illustrate, e. g., Labor Board v. Babcock & Wilcox Co., 351 U. S. 105; Labor Board v. United Steelworkers, 357 U. S. 357; Labor Board v. Insurance Agents, 361 U. S. 477, its findings here are supported by substantial evidence, Universal Camera Corp. v. Labor Board, 340 U. S. 474, its explication is not inadequate, irrational or arbitrary, compare Phelps Dodge Corp. v. Labor Board, 313 U. S. 177, 196-197; Labor Board v. United Steeworkers, supra, and it did not.exceed its powers or venture into an area barred by the statute. Compare Labor Board v. Insurance Agents, supra. The matter before the Board lay well within the mainstream of its duties. It was attempting to deal with an issue which Congress had placéd in its hands and “where Congress has in the statute given the Board a question to answer, .the courts will give respect to that answer.” Labor Board v. Insurance Agents, supra, at 499. Here, as in other cases, we must recognize the Board’s special function of applying the general provisions of the Act to the complexities of industrial life, Republic Aviation Corp. v. Labor Board, 324 U. S. 793, 798; Phelps Dodge Corp. v. Labor Board, supra, at 194, and of “[appraising] carefully the interests of both sides of any labor-management controversy in the diverse circumstances of particular cases” from its special understanding of “the actualities of industrial relations.” Labor Board v. United Steelworkers, supra, at 362-363. “The ultimate problem is the balancing of the conflicting legitimate interests. The function of striking that balance to effectuate national labor policy is often a difficult and delicate responsibility, which the Congress committed primarily to the National Labor Relations Board, subject to limited judicial review.” Labor Board v. Truck Drivers Union, 353 U. S. 87, 96.

Consequently, because the Board’s judgment was that ■ the claimed business purpose, would not outweigh the *237necessary harm to employee rights: — & judgment which we sustain — it could properly put aside evidence of respondent’s motive and decline to find whether the conduct was or was not prompted by the claimed business purpose. We reverse the judgment of the Court , of Appeals and remand the case to that court since its review was a limited one and it must now reach the remaining questions before it, including the propriety of the remedy which at least in part turns upon the Board’s construction of the settlement agreement as being no barrier to an award not only of reinstatement but of back pay as well.14

Reversed and remanded.

Mr. Justice Harlan,

concurring.

I agree with the Court that the Board’s conclusions respecting this 20-year “superseniority” plan were justified without inquiry into the respondents’ motives. However, I do not think that the same thing would necessarily be true in all circumstances, as for. example with a plan providing for a much shorter period of extra seniority. Being unsure whether the Court intends to hold that the Board has power to outlaw all such plans, irrespective of the employer’s motives and other circumstances, or only to sustain its action in the particular circumstances of this case, I concur in the judgment.

Mr. Justice Stewart

delivered the opinion of the Court.

The American Ship Building Company seeks review of a decision of the United States Court of Appeals for the District of Columbia Circuit enforcing an order of the National Labor Relations Board which found that the company had committed an unfair labor practice under §§8(a)(1) and (3) of the National Labor Relations Act.1 The question presented is that expressly reserved in Labor Board v. Truck Drivers Local Union, 353 U. S. 87, 93; namely, whether an employer commits an unfair labor practice under these sections of the Act when he temporarily lays off or “locks out” his employees during a labor dispute to bring economic pressure in support of *302his bargaining position. To resolve an asserted conflict among the circuits2 upon this important question of federal labor law we granted certiorari, 379 U. S. 814.

The American Ship Building Company operates four shipyards on the Great Lakes — at Chicago, at Buffalo, and at Toledo and Lorain, Ohio. The company is primarily engaged in the repairing of ships, a highly seasonal business concentrated in the winter months when the freezing of the Great Lakes renders shipping impossible. What limited business is obtained during the shipping season is frequently such that speed of execution is of the utmost importance to minimize immobilization of the ships.

Since 1952 the employer has engaged in collective bargaining with a group of eight unions. Prior to the negotiations here in question, the employer had contracted with the unions on five occasions, each agreement having been preceded by a strike. The particular chapter of the collective bargaining history with which we are concerned opened shortly before May 1, 1961, when the unions notified the company of their intention to seek modification of the current contract, due to expire on August 1.

At the initial bargaining meeting on June 6, 1961, the company took the position that its competitive situation would not allow increased compensation. The unions countered with demands for increased fringe benefits and some unspecified wage increase. Several meetings were held in June and early July during which negotiations focussed upon the fringe benefit questions without any substantial progress. At the last meeting, the parties resolved to call in the Federal Mediation and Concilia*303tion Service, which set the next meeting for July 19. At this meeting, the unions first unveiled their demand for a. 20-cents-an-hour wage increase and proposed a six-month extension of the contract pending continued negotiations. The employer rejected the proposed extension because it would have led to expiration during the peak season.

Further negotiations narrowed the dispute to five or six issues, all involving substantial economic differences. On July 31, the eve of the contract’s expiration, the employer made a proposal; the unions countered with another, revived their proposal for a six-month extension, and proposed in the alternative that the existing contract, with its no-strike clause, be extended indefinitely with the terms of the new contract to be made retroactive to August 1.3 After rejection of the proposed extensions, the employer’s proposal was submitted to the unions’ membership; on August 8 the unions announced that this proposal had been overwhelmingly rejected. The following day, the employer made another proposal which the unions refused to submit to their membership; the unions made no counteroffer and the parties separated without setting a date for further meetings, leaving this to the discretion of the conciliator.

Thus on August 9, after extended negotiations, the parties separated without having resolved substantial differences on the central issues dividing them and without having specific plans for further attempts to resolve them — a situation which the trial examiner found was an impasse. Throughout the negotiations, the employer displayed anxiety as to the unions’ strike plans, fearing that the unions would call a strike as soon as a ship entered the Chicago yard or delay negotiations into the winter to *304increase strike leverage. The union negotiator consistently insisted that it was his intention to reach an agreement without calling a strike; however, he did concede incomplete control over the workers — a fact borne out by the occurrence of a wildcat strike in February 1961. Because of the danger of an unauthorized strike and the consistent and deliberate use of strikes in prior negotiations, the employer remained apprehensive of the possibility of a work stoppage.

In light of the failure to reach an agreement and the lack of available work, the employer decided to lay off certain of its workers. On August 11 the employees received a notice which read: “Because of the labor dispute which has been unresolved since August 1, 1961, you are laid off until further notice.” The Chicago yard was completely shut down and all but two employees laid off at the Toledo yard. A large force was retained at Lorain to complete a major piece of work there and the employees in the Buffalo yard were gradually laid off as miscellaneous tasks were completed. Negotiations were resumed shortly after these layoffs and continued for the following two months until a two-year contract was agreed upon on October 27. The employees were recalled the following day.

Upon claims filed by the unions, the General Counsel of the Board issued a complaint charging the employer with violations of §§8 (a)(1), (3), and (5).4 The trial examiner found that although there had been no work in the Chicago yard since July 19, its closing was not due to lack of work. Despite similarly slack seasons in the past, the employer had for 17 years retained a nucleus crew to do maintenance work and remain ready to take such work as might come in. The examiner went on to find that the employer was reasonably apprehensive *305of a strike at some point. Although the unions had given assurances that there would be no strike, past bargaining history was thought to justify continuing apprehension that the unions would fail to make good their assurances. It was further found that the employer’s primary purpose in locking out its employees was to avert peculiarly harmful economic consequences which would be imposed on it and its customers if a strike were called either while a ship was in the yard during the shipping season or later when the yard was fully occupied. The examiner concluded that the employer:

“was economically justified and motivated in laying off its employees when it did, and that the fact that its judgment was partially colored by its intention to break the impasse which existed is immaterial in the peculiar and special circumstances of this case. Respondent, by its actions, therefore, did not violate Section 8 (a)(1), (3), and (5) of the Act.”

A three-to-two majority of the Board rejected the trial examiner’s conclusion that the employer could reasonably anticipate a strike. Finding the unions’ assurances sufficient to dispel any such apprehension, the Board was able to find only one purpose underlying the layoff: a desire to bring economic pressure to secure prompt settlement of the dispute on favorable terms. The Board did not question the examiner’s finding that the layoffs had not occurred until after a bargaining impasse had been reached. Nor did the Board remotely suggest that the company’s decision to lay off its employees was based either on union hostility or on a desire to avoid its bargaining obligations under the Act. The Board concluded that the employer “by curtailing its operations at the South Chicago yard with the consequent layoff of the employees, coerced employees in the exercise of their bargaining rights in violation of Section 8 (a)(1) of the Act, *306and discriminated against its employees within the meaning of Section 8 (a) (3) of the Act.” 5 142 N. L. R. B., at 136A-1365.

The difference between the Board and the trial examiner is thus a narrow one turning on their differing assessments of the circumstances which the employer claims gave it reason to anticipate a strike. Both the Board and the examiner assumed, within the established pattern of Board analysis,6 that if the employer had shut down its yard and laid off its workers solely for the purpose of bringing to bear economic pressure to break an impasse and secure more favorable contract terms, an unfair labor practice would be made out. “The Board has held that, absent special circumstances, an employer may not during bargaining negotiations either threaten to lock out or lock out his employees in aid of his bargaining position. Such conduct the Board has held presumptively infringes upon the collective-bargaining rights of employees in violation of Section 8 (a)(1) and the lockout, with its consequent layoff, amounts to discrimination within the meaning of Section 8 (a) (3). In addition, the Board has held that such conduct subjects the Union and the employees it represents to unwarranted and illegal pressure and creates an atmosphere in which the free opportunity for negotiation contemplated by Section 8 (a) (5) *307does not exist.” Quaker State Oil Refining Corp., 121 N. L. R. B. 334, 337.

The Board has, however, exempted certain classes of lockouts from proscription. “Accordingly, it has held that lockouts are permissible to safeguard against . . . loss where there is reasonable ground for believing that a strike was threatened or imminent.” Ibid. Developing this distinction in its rulings, the Board has approved lockouts designed to prevent seizure of a plant by a sitdown strike, Link-Belt Co., 26 N. L. R. B. 227; to forestall repetitive disruptions of an integrated operation by “quickie” strikes, International Shoe Co., 93 N. L. R. B. 907; to avoid spoilage of materials which would result from a sudden work stoppage, Duluth Bottling Assn., 48 N. L. R. B. 1335; and to avert the immobilization of automobiles brought in for repair, Betts Cadillac Olds, Inc., 96 N. L. R. B. 268. In another distinct class of cases the Board has sanctioned the use of the lockout by a multiemployer bargaining unit as a response to a whipsaw strike against one of its members. Buffalo Linen Supply Co., 109 N. L. R. B. 447, rev’d sub nom. Truck Drivers Union v. Labor Board, 231 F. 2d 110, rev’d, 353 U. S. 87.7

In analyzing the status of the bargaining lockout under §§ 8 (a) (1) and (3) of the National Labor Relations Act, it is important that the practice with which we are here concerned be distinguished from other forms of temporary separation from employment. No one would deny that an employer is free to shut down his enterprise tem*308porarily for reasons of renovation or lack of profitable work unrelated to his collective bargaining situation. Similarly, we put to one side cases where the Board has concluded on the basis of substantial evidence that the employer has used a lockout as a means to injure a labor organization or to evade his duty to bargain collectively. Hopwood Retinning Co., 4 N. L. R. B. 922; Scott Paper Box Co., 81 N. L. R. B. 535. What we are here concerned with is the use of a temporary layoff of employees solely as a means to bring economic pressure to bear in support of the employer’s bargaining position, after an impasse has been reached. This is the only issue before us, and all that we decide.8

To establish that this practice is a violation of § 8 (a) (1), it must be shown that the employer has interfered with, restrained, or coerced employees in the exercise of some right protected by § 7 of the Act. The Board’s position is premised on the view that the lockout interferes with two of the rights guaranteed by § 7: the right to bargain collectively and the right to strike. In the Board’s view, the use of the lockout “punishes” employees for the presentation of and adherence to demands made by their bargaining representatives and so coerces them in the exercise of their right to bargain collectively. It is important to note that there is here no allegation that the employer used the lockout in the service of designs inimical to the process of collective bargaining. There was no evidence and no finding that the employer was hostile to its employees’ banding together for collective bargaining or that the lockout was designed to discipline *309them for doing so. It is therefore inaccurate to say that the employer’s intention was to destroy or frustrate the process of collective bargaining. What can be said is that it intended to resist the demands made of it in the negotiations and to secure modification of these demands. We cannot see that this intention is in any way inconsistent with the employees’ rights to bargain collectively.

Moreover, there is no indication, either as a general matter or in this specific case, that the lockout will necessarily destroy the unions’ capacity for effective and responsible representation. The unions here involved have vigorously represented the employees since 1952, and there is nothing to show that their ability to do so has been impaired by the lockout. Nor is the lockout one of those acts which are demonstrably so destructive of collective bargaining that the Board need not inquire into employer motivation, as might be the case, for example, if an employer permanently discharged his unionized staff and replaced them with employees known to be possessed of a violent antiunion animus. Cf. Labor Board v. Erie Resistor Corp., 373 U. S. 221. The lockout may well dissuade employees from adhering to the position which they initially adopted in the bargaining, but the right to bargain collectively does not entail any “right” to insist on one’s position free from economic disadvantage. Proper analysis of the problem demands that the simple intention to support the employer’s bargaining position as to compensation and the like be distinguished from a hostility to the process of collective bargaining which could suffice to render a lockout unlawful. See Labor Board v. Brown, ante, p. 278.

The Board has taken the complementary view that the lockout interferes with the right to strike protected under *310§§ 7 and 13 of the Act9 in that it allows the employer to pre-empt the possibility of a strike and thus leave the union with “nothing to strike against.” Insofar as this means that once employees are locked out, they are deprived of their right to call a strike against the employer because he is already shut down, the argument is wholly specious, for the work stoppage which would have been the object of the strike has in fact occurred.10 It is true that recognition of the lockout deprives the union of exclusive control of the timing and duration of work stoppages calculated to influence the result of collective bargaining negotiations, but there is nothing in the statute which would imply that the right to strike “carries with it” the right exclusively to determine the timing and duration of all work stoppages. The right to strike as commonly understood is the right to cease work — nothing more. No doubt a union’s bargaining power would be enhanced if it possessed not only the simple right to strike but also the power exclusively to determine when work stoppages should occur, but the Act’s provisions are not indefinitely elastic, content-free forms to be shaped in whatever manner the Board might think best conforms to the proper balance of bargaining power.

Thus, we cannot see that the employer’s use of a lockout solely in support of a legitimate bargaining position is in any way inconsistent with the right to bargain collectively or with the right to strike. Accordingly, we con-*311elude that on the basis of the findings made by the Board in this ease, there has been no violation of § 8 (a)(1).

Section 8 (a)(3) prohibits discrimination in regard to tenure or other conditions of employment to discourage union membership. Under the words of the statute there must be both discrimination and a resulting discouragement of union membership. It has long been established that a finding of violation under this section will normally turn on the employer’s motivation. See Labor Board v. Brown, ante, p. 278; Radio Officers’ Union v. Labor Board, 347 U. S. 17, 43; Labor Board v. Jones & Laughlin Steel Corp., 301 U. S. 1, 46. Thus when the employer discharges a union leader who has broken shop rules, the problem posed is to determine whether the employer has acted purely in disinterested defense of shop discipline or has sought to damage employee organization. It is likely that the discharge will naturally tend to discourage union membership in both cases, because of the loss of union leadership and the employees’- suspicion of the employer’s true intention. But we have consistently construed the section to leave unscathed a wide range of employer actions taken to serve legitimate lousiness interests in some significant fashion, even though the act committed may tend to discourage union membership. See, e. g., Labor Board v. Mackay Radio & Telegraph Co., 304 U. S. 333, 347. Such a construction of § 8 (a)(3) is essential if due protection is to be accorded the employer’s right to manage his enterprise. See Textile Workers v. Darlington Mfg. Co., ante, p. 263.

This is not to deny that there are some practices which are inherently so prejudicial to union interests and so devoid of significant economic justification that no specific evidence of intent to discourage union membership or other antiunion animus is required. In some cases, it may be that the employer’s conduct carries with it an inference of unlawful intention so compelling that it is *312justifiable to disbelieve the employer’s protestatiQns of innocent purpose. Radio Officers’ Union v. Labor Board, supra, at 44-45; Labor Board v. Erie Resistor Corp., supra. Thus where many have broken a shop rule, but only union leaders have been discharged, the Board need not listen too long to the plea that shop discipline was simply being enforced. In other situations, we have described the process as the “far more delicate task . . . of weighing the interests of employees in concerted activity against the interest of the employer in operating his business in a particular manner . . . .” Labor Board v. Erie Resistor Corp., supra, at 229.

But this lockout does not fall into that category of cases arising under §8 (a)(3) in which the Board may truncate its inquiry into employer motivation. As this case well shows, use of the lockout does not carry with it any necessary implication that the employer acted to discourage union membership or otherwise discriminate against union members as such. The purpose and effect of the lockout were only to bring pressure upon the union to modify its demands. Similarly, it does not appear that the natural tendency of the lockout is severely to discourage union membership while serving no significant employer interest. In fact, it is difficult to understand what tendency to discourage union membership or otherwise discriminate against union members was perceived by the Board. There is no claim that the employer locked out only union members, or locked out any employee simply because he was a union member; nor is it alleged that the employer conditioned rehiring upon resignation from the union. It is true that the employees suffered economic disadvantage because of their union’s insistence on demands unacceptable to the employer, but this is also true of many steps which an employer may take during a bargaining conflict, and the existence of an arguable possibility that someone may feel himself *313discouraged in his union membership or discriminated against by reason of that membership cannot suffice to label them violations of § 8 (a) (3) absent some unlawful intention. The employer’s permanent replacement of strikers (Labor Board v. Mackay Radio & Telegraph Co., supra), his unilateral imposition of terms (Labor Board v. Tex-Tan, Inc., 318 F. 2d 472, 479-482), or his simple refusal to make a concession which would terminate a strike — all impose economic disadvantage during a bargaining conflict, but none is necessarily a violation of 18(a)(3).

To find a violation of § 8 (a) (3), then, the Board must find that the employer acted for a proscribed purpose. Indeed, the Board itself has always recognized that certain “operative” or “economic” purposes would justify a lockout. But the Board has erred in ruling that only these purposes will remove a lockout from the ambit of § 8 (a)(3), for that section requires an intention to discourage union membership or otherwise discriminate against the union. There was not the slightest evidence and there was no finding that the employer was actuated by a desire to discourage membership in the union as distinguished from a desire to affect the outcome of the particular negotiations in which it was involved. We recognize that the “union membership” which is not to be discouraged refers to more than the payment of dues and that measures taken to discourage participation in protected union activities may be found to come within the proscription. Radio Officers’ Union v. Labor Board, supra, at 39-40. However, there is nothing in the Act which gives employees the right to insist on their contract demands, free from the sort of economic disadvantage which frequently attends bargaining disputes. Therefore, we conclude that where the intention proven is merely to bring about a settlement of a labor dispute on favorable terms, no violation of § 8 (a)(3) is shown.

*314The conclusions which we draw from analysis of §§8 (a)(1) and (3) are consonant with what little of relevance can be drawn from the balance of the statute and its legislative history. In the original version of the Act, the predecessor of § 8 (a)(1) declared it an unfair labor practice “[t]o attempt, by interference, influence, restraint, favor, coercion, or lockout, or by any other means, to impair the right of employees guaranteed in section 4.” 11 Prominent in the criticism leveled at the bill in the Senate Committee hearings was the charge that it did not accord even-handed treatment to employers and employees because it prohibited the lockout while protecting the strike.12 In the face of such criticism, the Committee added a provision prohibiting employee interference with employer bargaining activities13 and deleted the reference to the lockout.14 A plausible inferenee to be drawn from this history is that the language was de*315leted to mollify those who saw in the bill an inequitable denial of resort to the lockout, and to remove any language which might give rise to fears that the lockout was being proscribed per se. It is in any event clear that the Committee was concerned with the status of the lockout and that the bill, as reported and as finally enacted, contained no prohibition on the use of the lockout as such.

Although neither § 8 (a)(1) nor § 8 (a)(3) refers specifically to the lockout, various other provisions of the National Labor Relations Act do refer to the lockout, and these references can be interpreted as a recognition of the legitimacy of the device as a means of applying economic pressure in support of bargaining positions. Thus 29 U. S. C. § 158 (d)(4) (1958 ed.) prohibits the use of a strike or lockout unless requisite notice procedures have been complied with; 29 U. S. C. § 173 (c) (1958 ed.) directs the Federal Mediation and Conciliation Service to seek voluntary resolution of labor disputes without resort to strikes or lockouts; and 29 U. S. C. §§ 176, 178 (1958 ed.), authorize procedures whereby the President can institute a board of inquiry to forestall certain strikes or lockouts. The correlative use of the terms "strike” and “lockout” in these sections contemplates that lockouts will be used in the bargaining process in some fashion. This is not to say that these provisions serve to define the permissible scope of a lockout by an employer. That, in the context of the present case, is a question ultimately to be resolved by analysis of §§ 8 (a)(1) and (3).

The Board has justified its ruling in this case and its general approach to the legality of lockouts on the basis of its special competence to weigh the competing interests of employers and employees and to accommodate these interests according to its expert judgment. "The Board has reasonably concluded that the availability of such a weapon would so substantially tip the scales in the employer’s favor as to defeat the Congressional purpose of *316placing employees on a par with their adversary at the bargaining table.” 15 To buttress its decision as to the balance struck in this particular case, the Board points out that the employer has been given other weapons to counterbalance the employees’ power of strike. The employer may permanently replace workers who have gone out on strike, or, by stockpiling and subcontracting, maintain his commercial operations while the strikers bear the economic brunt of the work stoppage. Similarly, the employer can institute unilaterally the working conditions which he desires once his contract with the union has expired. Given these economic weapons, it is argued, the employer has been adequately equipped with tools of economic self-help.

There is of course no question that the Board is entitled to the greatest deference in recognition of its special competence in dealing with labor problems. In many areas its evaluation of the competing interests of employer, and employee should unquestionably be given conclusive effect in determining the application of §§ 8 (a)(1), (3), and (5). However, we think that the Board construes its functions too expansively when it claims general authority to define national labor policy by balancing the competing interests of labor and management.

While a primary purpose of the National Labor Relations Act was to redress the perceived imbalance of economic power between labor and management, it sought to accomplish that result by conferring certain affirmative rights on employees and by placing certain enumerated restrictions on the activities of employers. The Act prohibited acts which interfered with, restrained, or coerced employees in the exercise of their rights to organize a union, to bargain collectively, and to strike; it proscribed *317discrimination in regard to tenure and other conditions of employment to discourage membership in any labor organization. The central purpose of these provisions was to protect employee self-organization and the process of collective bargaining from disruptive interferences by employers. Having protected employee organization in countervailance to the employers’ bargaining power, and having established a system of collective bargaining whereby the newly coequal adversaries might resolve their disputes, the Act also contemplated resort to economic weapons should more peaceful measures not avail. Sections 8(a)(1) and (3) do not give the Board a general authority to assess the relative economic power of the adversaries in the bargaining process and to deny weapons to one party or the other because of its assessment of that party’s bargaining power. Labor Board v. Brown, ante, p. 278. In this case the Board has, in essence, denied the use of the bargaining lockout to the employer because of its conviction that use of this device would give the employer “too much power.” In so doing, the Board has stretched §§ 8 (a)(1) and (3) far beyond their functions of protecting the rights of employee organization and collective bargaining. What we have recently said in a closely related context is equally applicable here:

“•[W]hen the Board moves in this area ... it is functioning as an arbiter of the sort of economic weapons the parties can use in seeking to gain acceptance of their bargaining demands. It has sought to introduce some standard of properly ‘balanced’ bargaining power, or some new distinction of justifiable and unjustifiable, proper and ‘abusive’ economic weapons into . . . the Act. ... We have expressed our belief that this amounts to the Board’s entrance into the substantive aspects of the *318bargaining process to an extent Congress has not countenanced.” Labor Board v. Insurance Agents’ International Union, 361 U. S. 477, 497-498.

We are unable to find that any fair construction of the provisions relied on by the Board in this case can support its finding of an unfair labor practice. Indeed, the role assumed by the Board in this area is fundamentally inconsistent with the structure of the Act and the function of the sections relied upon. The deference owed to an expert tribunal cannot be allowed to slip into a judicial inertia which results in the unauthorized assumption by an agency of major policy decisions properly made by Congress. Accordingly, we hold that an employer violates neither § 8 (a)(1) nor § 8 (a) (3) when, after a bargaining impasse has been reached, he temporarily shuts down his plant and lays off his employees for the sole purpose of bringing economic pressure to bear in support of his legitimate bargaining position.

Reversed.

Mr. Justice White,

concurring in the result.

The Court today holds that the use of economic weapons by an employer for the purpose of improving his bargaining position can never violate the broad provisions of §| 8 (a)(1) and (3) of the NLRA and hence a bargaining lockout of employees in resistance to demands of a union is invariably exempt from the proscriptions of the Act. As my Brother Goldberg well points out, the Court applies legal standards that cannot be reconciled with decisions of this Court defining the Board’s functions in applying these sections of the Act and does so without pausing to ascertain if the Board’s factual premises are supported by substantial evidence. I also think the Court, in the process of establishing the legality of a bargaining lockout, overlooks the uncontradicted facts in this *319record and the accepted findings of the trial examiner which indicate to me that the employer’s closing of the Chicago yard was not a “lockout” for the purpose of bringing economic pressure to break an impasse and to secure more favorable contract terms.

In my view the issue posed in this case is whether an employer who in fact anticipates a strike may inform customers of this belief to protect his commercial relationship with customers and to safeguard their property, thereby discouraging business, and then lay off employees for whom there is no available work. I, like the trial examiner, think he may, and do not think this conduct can be impeached under §§ 8 (a)(1) and (3) by merely asserting that the employer and his customers were erroneous in believing a strike was imminent.

The Board, the Court of Appeals, and presumably this Court, accept all the findings of the trial examiner, except the finding that the employer’s honest belief that a strike would occur had a reasonable basis in fact. The examiner found that at the time of the layoffs at the Chicago yard there was no work there and very little at the other yards, which remained open until all available work was completed. During past slack summer seasons a nucleus crew had been retained at the yards to perform emergency repair jobs for Ship Building’s 14 or 15 regular customers. Absent a job, these employees also did maintenance work, but the accommodation of these regular customers and retention of their good will was the only reason for remaining open, the operations being otherwise unprofitable. The customers learned of the labor unrest at the yards through newspaper accounts and Ship Building’s plant managers, who felt constrained to tell long-standing customers of the possibility of a strike during the course of repair work. The manager of the Buffalo yard was of the opinion that “the owner that brought the boat into the dock would have rocks in his head if he would have *320taken the chance.” Work was not refused, however. There were few, if any, requests for repairs during that summer, a substantial number of shipowners being reluctant to bring their vessels into the yard. The last job left the Chicago yard three weeks before closing. The examiner found that at the time of closing, Ship Building had “men working on maintenance in the yards, with no work on hand, none anticipated, and customers refusing to send work in.” Only those workers for whom there was no work were laid off and no new jobs were taken on. The examiner noted that the employer was not unaware of the union’s negotiating strategy and of the possible effect of a closing on this strategy. But in carefully assessing all the testimony he found that at most these considerations partially colored the employer’s motivation. The examiner concluded from these facts that “the economic inducements so overshadowed anything improper that they must be considered primary, particularly when the economic factors which supported them arose through no fault of Respondent and anteceded the layoff.”

Given the finding that the closing was due to lack of work at the Chicago yard, it is no answer to say, as the Board does, that there was no reasonable basis to anticipate a strike and hence the closing was an offensive bargaining lockout. Whether there was a reasonable basis to fear a strike or not, the fact remains that the employer, and its customers, did fear a strike, and consequently there was no work for the employees. It has long been the law that an employer is free to modify or shut down operations temporarily for business reasons unrelated to the exercise by his employees of statutory rights, and the reasonableness of an employer’s response to business exigencies is not ordinarily subject to review. See Pepsi-Cola Bottling Co., 145 N. L. R. B. 785 (1964); Associated General Contractors of America, Inc., 105 N. L. R. B. 767 (1953); cf. Fibreboard Paper Products v. Labor Board, 379 *321U. S. 203; Textile Workers Union v. Darlington Mfg. Co., decided today, ante, p. 263. There is nothing in the decisions of the NLRB, including this case, which would indicate that there are occasions when an employer may not truthfully inform his customers of a labor dispute and his fear of a strike to protect his business and their property and may not lay off employees for lack of work. Indeed, these decisions hold that an employer may shut down in response to such economic conditions, even though these conditions are the result of protected concerted activities, Pepsi-Cola Bottling Co., 145 N. L. R. B. 785 (1964); Associated General Contractors of America, Inc., 105 N. L. R. B. 767 (1953); H. H. Zimmerli, 133 N. L. R. B. 1217 (1961), so long as the creation of or alleged reliance on these conditions is not a subterfuge for a lockout, Ripley Mfg. Co., 138 N. L. R. B. 1452 (1962); Savoy Laundry, Inc., 137 N. L. R. B. 306 (1962); New England Web, Inc., 135 N. L. R. B. 1019 (1962). There is no evidence here that the lack of work was a result of the employer’s decision or desire to lay off its employees and the Board did not so find. I do not now determine whether a temporary economic shutdown could ever be found to violate the Act. Here the Board has given no reasons, no rationale, to show how this closing violated the Act, except to say the closing was a bargaining lockout. A lockout is the refusal by an employer to furnish available work to his regular employees. It is apparent that the considerations which fault an employer for refusing to furnish available work are quite different from those which would prohibit him from laying off workers for whom there is no work. Hence, reliance on the Board’s lockout cases does not explain, no less support, the result reached in this case. The compelling conclusion is that the Board has failed to “disclose the basis of its order” and to “give clear indication that it has exercised the discretion with which Congress has empowered it.” Phelps Dodge Corp. v. Labor *322 Board, 313 U. S. 177, 197. This is not to say the Board has reached an erroneous balance in regard to the bargaining lockout; it is to say that the bargaining lockout analysis will not suffice to judge the legality of the layoffs in this case.

The Court, like the Board, assimilates the employer’s conduct here to the bargaining lockout and restrikes the balance; it dismisses the actual justification for the closing with the assertion that the “examiner found . . . [the] closing was not due to lack of work. Despite similarly slack seasons in the past, the employer had for 17 years retained a nucleus crew to do maintenance work and remain ready to take such work as might come in.” Ante, at 304. This, is puzzling, since the examiner found precisely the contrary, land neither the Board nor the Court of Appeals took issue with these findings. The examiner said that a nucleus crew was maintained in the past only in the expectation of emergency work, the performance of such work being thought necessary to maintain customer good will. Because of the labor uncertainty and the decision that undertaking emergency jobs would jeopardize customer relations, there was no expectation of work during the summer of 1961, unlike past years. Since I think an employer’s decision to lay off employees because of lack of work is not ordinarily barred by the Act, and since neither the Board nor the Court properly can ignore this claim, I would reverse the Board’s order, but without reaching out to decide an issue not at all presented by this case.

Since the Court does rule on the status of the bargaining lockout under the National Labor Relations Act, I feel constrained to state my views. This Court has long recognized that the Labor Relations Act “did not undertake the impossible task of specifying in precise and unmistakable language each incident which would constitute an unfair labor practice,” but “left to the Board the *323work of applying the Act’s general prohibitory language in the light of the infinite combinations of events which might be charged as violative of its terms.” Republic Aviation Corp. v. Labor Board, 324 U. S. 793, 798. Thus the legal status of the bargaining lockout, as the Court indicated in Labor Board v. Truck Drivers Union, 353 U. S. 87, 96, is to be determined by “the balancing of the conflicting legitimate interests.”

The Board has balanced these interests here — the value of the lockout as an economic weapon against its impact on protected concerted activities, including the right to strike, for which the Act has special solicitude, Labor Board v. Erie Resistor Corp., 373 U. S. 221, 234 — and has determined that the employer’s interest in obtaining a bargaining victory does not outweigh the damaging consequences of the lockout. It determined that for an employer to deprive employees of their livelihood because of demands made by their representatives and in order to compel submission to the employer’s demands, coerces employees in their exercise of the right to bargain collectively and discourages resort to that right. And this interferes with the right to strike, sharply reducing the effectiveness of that weapon and denying the union control over the timing of the economic contest. The Court rejects this reasoning on the ground that the lockout is not conduct “demonstrably so destructive of collective bargaining that the,Board need not inquire into employer motivation.” Ante, at 309. Since the employer’s true motive is to bring about settlement of the dispute on favorable terms, there can be no substantial discouragement of union membership or interference with concerted activities. And the right to strike is only the right to cease work, which the lockout only encourages rather than displaces.

This tour de force denies the Board’s assessment of the impact on employee rights and this truncated definition *324of the right to strike, nowhere supported in the Act, is unprecedented. Until today the employer’s true motive or sole purpose has not always been determinative of the impact on employee rights. Republic Aviation Corp. v. Labor Board, 324 U. S. 793; Radio Officers’ Union v. Labor Board, 347 U. S. 17; Labor Board v. Truck Drivers Union, 353 U. S. 87; Labor Board v. Erie Resistor Corp., 373 U. S. 221; Labor Board v. Burnup & Sims, Inc., 379 U. S. 21. The importance of the employer’s right to hire replacements to continue operations, or of his right to fire employees he has good reason to believe are guilty of gross misconduct was not doubted in Erie Resistor and Burnup & Sims. Nonetheless the Board was upheld in its determination that the award of super-seniority to strike replacements and discharge of the suspected employee were unfair labor practices. Of course, such conduct is taken in the pursuit of legitimate business ends, but nonetheless the “conduct does speak for itself ... it carries with it unavoidable consequences which the employer not only foresaw but which he must have intended.” Erie Resistor, 373 U. S., at 228. I would have thought it apparent that loss of jobs for an indefinite period, and the threatened loss of jobs, which the Court’s decision assuredly sanctions, cf. Textile Workers Union v. Darlington Mfg. Co., decided today, ante, at 274, n. 20, because of the union’s negotiating activity, itself protected conduct under § 7, hardly encourage affiliation with a union.

If the Court means what it says today, an employer may not only lock out after impasse consistent with §§ 8 (a) (1) and (3), but replace his locked-out employees with temporary help, cf. Labor Board v. Brown, ante, p. 278, or perhaps permanent replacements, and also lock out long before an impasse is reached. Maintaining operations during a labor dispute is at least equally as important an interest as achieving a bargaining victory, see *325 Labor Board v. Mackay Radio & Telegraph Co., 304 U. S. 333, and a shutdown during or before negotiations advances an employer’s bargaining position as much as a lockout after impasse. And the hiring of replacements is wholly consistent with the employer’s intent “to resist the demands made of it in the negotiations and to secure modification of these demands.” Ante, at 309. I would also assume that under §§ 8 (a)(1) and (3) he may lock out for the sole purpose of resisting the union’s assertion of grievances under a collective bargaining contract, absent a no-lockout clause. Given these legitimate business purposes, there is no antiunion motivation, and absent such motivation, a lockout cannot be deemed destructive of employee rights. “[I]nquiry into employer motivation” may not be truncated. Ante, at 312. “Proper analysis of the problem demands that the simple intention to support the employer’s bargaining position as to compensation and the like be distinguished from a hostility to the process of collective bargaining which could suffice to render a lockout unlawful.” Ante, at 309. I think that the Board may assess the impact of a bargaining lockout on protected employee rights, without regard to motivation, and that the Court errs in failing to give due consideration to the Board’s conclusions in this regard.

The balance and accommodation of “conflicting legitimate interests” in labor relations does not admit of a simple solution and a myopic focus on the true intent or motive of the employer has not been the determinative standard of the Board or this Court. As the Court points out, there are things an employer may do for business reasons which are inconsistent with a rigid or literal interpretation of employee rights under the Act, such as the right to hire strike replacements. Labor Board v. Mackay Radio & Telegraph Co., 304 U. S. 333. But there are just as clearly others which he may not. Republic *326 Aviation, 324 U. S. 793; Erie Resistor, 373 U. S. 221; Burnup & Sims, 379 U. S. 21. A literal interpretation will not suffice to reconcile these cases, nor to justify the result in the present case. For in saying an employer may lock out all his employees, the Court fully ignores the most explicit statutory right of employees “to refrain from any or all [concerted] activities.” Nor can these cases be explained by the Court's test that employer conduct is not proscribed unless it is “inherently so prejudicial to union interests and so devoid of significant economic justification,” ante, at 311, that true motivation need not be independently shown. The test is clearly one of choosing among several motivations or purposes and weighing the respective interests of employers and employees. And I think that is the standard the Court applies to the bargaining lockout in this case, but without heeding the fact the balance is for the Board to strike in the first instance.

The Board’s role in this area is a “delicate task, reflected in part in decisions of this Court, of weighing the interests of employees in concerted activity against the interest of the employer in operating his business in a particular manner.” Erie Resistor, 373 U. S., at 229. Its decisions are not immune from attack in this Court. Its findings must be supported by substantial evidence and its explication must fit the case before it, be adequate, and be based upon the policy of the Act and an acceptable reading of industrial realities. I would reverse the Board’s decision here because it has not articulated a rational connection between the facts found and the decision made. “This is not to deprecate, but to vindicate (see Phelps Dodge Corp. v. Labor Board, 313 U. S. 177, 197), the administrative process, for the purpose of the rule is to avoid 'propel[ling] the court into the domain which Congress has set aside exclusively for the administrative agency.’ 332 U. S., at 196.” Burlington Truck *327 Lines v. United States, 371 U. S. 156, 169. It is to ask the Board to show that it has exercised the discretion which it has under the Act. Such insistence on a reasoned decision is a foremost function of judicial review, especially where conflicting significant interests are sought to be accommodated. Compare Securities & Exchange Comm’n v. Chenery Corp., 318 U. S. 80, with Securities & Exchange Comm’n v. Chenery Corp., 332 U. S. 194. But this function is not to reject the Board’s reasoned assessment of the impact of a particular economic weapon on employee rights. It is certainly not to restrike the balance which the Board has reached.

Mr. Justice Goldberg,

with whom The Chief Justice joins,

concurring in the result.

I concur in the Court’s conclusion that the employer’s lockout in this case was not a violation of either § 8 (a) (1) or § 8 (a) (3) of the National Labor Relations Act, 49 Stat. 452, as amended, 29 U. S. C. §§ 158 (a)(1) and (3) (1958 ed.), and I therefore join in the judgment reversing the Court of Appeals. I reach this result not for the Court’s reasons, but because, from the plain facts revealed by the record, it is crystal clear that the employer’s lockout here was justifiable. The very facts recited by the Court in its opinion show that this employer locked out its employees in the face of a threatened strike under circumstances where, had the choice of timing been left solely to the unions, the employer and its customers would have been subject to economic injury over and beyond the loss of business normally incident to a strike upon the termination of the collective bargaining agreement. A lockout under these circumstances has been recognized by the Board itself to be justifiable and not a violation of the labor statutes. Betts Cadillac Olds, Inc., 96 N. L. R. B. 268; see Packard Bell Electronics Corp., 130 N. L. R. B. 1122; International Shoe Co., 93 N. L. R. B. 907; Duluth *328 Bottling Assn., 48 N. L. R. B. 1335; Quaker State Oil Refining Corp., 121 N. L. R. B. 334, 337.

The trial examiner for the Labor Board found that the employer reasonably and “honestly believed that a strike might take place immediately, or when a vessel was docked, or that bargaining would be delayed until closer to the winter months when Respondent would be more vulnerable,” 142 N. L. R. B., at 1382, and that the company “by its actions, therefore, did not violate . . . the Act,” 142 N. L. R. B., at 1383. The Board did not dispute the trial examiner’s finding that the employer in fact believed that a strike was threatened. Nor did it deny that if the employer reasonably believed that “there was a real strike threat,” the lockout would be justified. 142 N. L. R. B., at 1364. The Board, however, rejected the ultimate finding of the trial examiner because it disagreed with his conclusion that the employer “had reasonable grounds to fear a strike.” (Emphasis added.) 142 N. L. R. B., at 1363. The Court of Appeals in a single sentence sustained the Board’s holding on this point concluding, without detailed analysis, “that the Board’s finding that respondent had no reasonable basis for fearing a strike is not without the requisite record support.” 331 F. 2d 839, 840. In my view the Board’s conclusion that the employer’s admitted fear of a strike was unreasonable is not only without the requisite record support but is at complete variance with “the actualities of industrial relations,” Labor Board v. Steelworkers, 357 U. S. 357, 364, which the Board is to take into account in effectuating the national labor policy.

We do not deal with a case in which the facts are disputed and the Board has resolved testimonial controversies. The facts here are undisputed, and a review of them demonstrates that the employer’s fear of a strike at a time strategically selected by the unions to cause *329it maximum damage and to give the unions the maximum economic advantage was totally reasonable.

The employer company is primarily engaged in repairing ships and operates four shipyards on the Great Lakes at Buffalo, New York, Lorain and Toledo, Ohio, and South Chicago, Illinois. As the Court points out, the employer’s business is highly seasonal, concentrated in the winter months when the Great Lakes are frozen over and shipping is impossible. Speed is of the utmost importance in this business, for the shipping season is short and the tie-up of a ship for several weeks during the season or a delay in a ship’s re-entry into service in the spring produces a severe economic impact. A work stoppage while a ship is in the yards can have serious economic consequences both for the employer and for his customers. Customers are justifiably wary of entrusting their ships to the yards at a time when a collective bargaining dispute is unresolved. For this reason the expiration date of a contract in situations such as this is a vital issue in collective bargaining. The employer seeks an expiration date during the slack season; the union seeks an expiration date during the busy season. In this case as a result of past bargaining, the employer’s contract expired on August 1, rather than during the busy season.

From 1952 until 1961, when the negotiations now under consideration began, the employer had negotiated five times with the eight unions here involved, and it had experienced exactly one strike per negotiation. The strikes in 1952, 1953, 1955, and 1956 lasted about three weeks each, and the 1958 strike continued for 10 weeks. In 1955 employees had engaged in a slowdown before the agreement expired and thereby caught an $8,000,000 ship in the yard, the use of which was lost to the customer for four weeks during its busiest season. In February 1961, at the height of the busy season, wildcat work stoppages occurred in Chicago and Buffalo.

*330Shortly before May 1961 the unions notified the employer that they wished to modify the contract due to expire on August 1. At the first bargaining meeting on June 6, 1961, the employer spokesman maintained that competitive conditions prevented any increase in wages or benefits. The unions took an opposite view and asked for a substantial increase in pension and other benefits. The parties met on numerous occasions throughout June and July. As the negotiations progressed, the employer receded from its original position and offered improved wages and benefits; the unions receded from some of their demands, but a meeting of the minds was not reached. On July 20 and subsequently, with the August 1 expiration date approaching, the unions proposed a six-month extension of the current contract. This would have given the unions an expiration date at a time most advantageous to them; the employer rejected this proposal on the grounds that the contract would then expire on February 1, 1962, the very height of its busy season, and that no customer would risk its ships by putting them in the company’s yards knowing that the labor contract was about to expire. On July 28 the unions’ negotiator informed the employer that the union members had voted “overwhelmingly to take a strike if necessary.” On July 31 the employer made a new and increased offer on wages and benefits, asked that its proposals be submitted to the employees for a vote and offered to extend the contract for the limited period sufficient to enable this vote to be taken. The unions in turn asked that the labor agreement be extended indefinitely until a new agreement was reached. The employer refused to agree to an indefinite extension of its present contract on the ground that it could then be struck at any time of the unions’ choosing.1

Although the contract expired on August 1, the unions did not call a strike on that date but continued to work *331on a day-to-day basis and submitted the employer’s revised offer to a vote of the membership. On August 8 the unions informed the employer that its proposals had been “overwhelmingly” rejected by the employees. On August 9 the employer made a new package offer on many issues. The union negotiators rejected this new offer, refused to take it to the employees for a vote, and made no counteroffer. Negotiations were broken off without any definite plans for further meetings between the parties. Future meetings were left to the call of a federal mediator.

Faced with the situation of an expired contract and the unions free to strike at any time, in particular at a time of their own choosing during the busy season, or whenever the yard was filled with ships, the employer decided to shut down the Chicago yard completely and lay off all but two employees at Toledo. Notices were issued to employees at Chicago, Toledo, and to some in Buffalo, which stated, “Because of the labor dispute which has been unresolved since August 1,1961, you are laid off until further notice.” Negotiations were resumed after this lockout and continued until agreement was reached on October 27. The laid off employees were then recalled to work. Since then the parties have engaged in other negotiations and have agreed upon contracts without either strike or lockout.

On this record the trial examiner held that the employer reasonably feared that the unions would strike when the time was ripe. He found that the employer reasonably believed that:

“[t]he Unions’ strategy was:

“Keep working at Lorain, keep the nonproductive men on the payroll as long as possible at the other yards until one of two things occurred: (a) A shipowner would send a ship into one of the yards, and then by striking, the Respondent would be forced to his knees in effecting a labor settlement satisfactory to the Union, and if this didn’t occur, then, (b) con*332tinue to bargain, into the winter months, and then execute an agreement effective in November, December, January, or February, and in this way, when the agreement was reopened, Respondent would be sure to have ships in its docks, and a strike at such a time would bring the Respondent to his knees in effecting an agreement.” 142 N. L. R. B., at 1381.

Accordingly the trial examiner held that no unfair labor practice was committed. This holding followed settled Board doctrine that “lockouts are permissible to safeguard against unusual operational problems or hazards or economic loss where there is reasonable ground for believing that a strike [is] . . . threatened or imminent.” Quaker State Oil Refining Corp., supra, at 337.

The Board overturned the trial examiner’s ultimate holding, reaching what, on this record, is a totally unsupportable conclusion — that the employer’s fear of a strike was unreasonable. The Board rested its conclusion upon the grounds that “the Unions made every effort to convey to the Respondent their intention not to strike; and they also gave assurances that if a strike were called, any work brought into Respondent’s yard before the strike would be completed. The Unions further offered to extend the existing contract [which contained a no-strike provision] for 6 months, or indefinitely, until contract terms were reached 142 N. L. R. B., at 1364. Upon analysis it is clear that none of these grounds will support the Board’s conclusion that the employer had no reasonable basis to fear a strike.

The Board’s finding that “the Unions made every effort to convey to the Respondent their intention not to strike” is based upon statements made by union negotiators during the course of the negotiations. The chief negotiator for the unions testified that on the first day of negotiations, “I stated that it was my understanding that *333in the past there seemed to have been a strike at every— during every negotiation since World War II from information I had received, and it was our sincere hope that we could negotiate this agreement — go through those negotiations and negotiate a new agreement without any strife, that personally I always had a strong dislike to strike and that I thought if two parties sincerely desired to reach an agreement, one could be reached without strike. The Company . . . stated that the Company concurred in those thoughts, that they too disliked strikes, and it was their hope, also, that an agreement could be reached amicably.” 2 The negotiators for the unions expressed this same sentiment on several other occasions during the negotiations.

These statements, which one would normally expect a union agent to make during the course of negotiations as a hopeful augury of their outcome rather than as a binding agreement not to strike, scarcely vitiate the reasonableness of the employer’s fear of a strike in light of the long history of past strikes by the same unions. Further, they cannot be deemed to render the employer’s fear of a strike unreasonable after the negotiations had reached an impasse, particularly in view of the fact that a strike vote had been taken by the unions’ membership, and the membership rather than the union representatives had final authority to determine whether a strike would take place.

The fact that the assistant business managers of Local 85 and Local 374 of the Boilermakers Union “gave assur-*334anees that if a strike were called, any work brought into Respondent’s yard before the strike would be completed” 3 likewise cannot be deemed to offset the unions’ threat of a strike and its consequences. These men were officials of locals in only one of the eight separate unions involved. At most they could give assurances as to a few of the men at two of the company’s four yards. And even had all of the unions joined in these statements, which was not the ease, the employer had been subject to wildcat strikes at a time when the unions were bound by a no-strike clause in their contract. Therefore, without impugning the good faith of these union agents, it surely was not unreasonable for the employer, notwithstanding this assurance, to fear that its employees might not complete work on ships when they were not bound by a no-strike clause.

The Board also relies on the fact that the unions offered a six-month extension of the present contract. As I have already pointed out, this would have caused the contract to expire during the employer’s busiest season. The employer had a perfect right to reject this stratagem. Had it agreed, the unions would have achieved one of their important objectives without the necessity of striking. By the same token it is clear that the unions would have agreed not to strike had the employer accepted their proposals for increases in wages and benefits. Surely the employer had every right to reject these proposals, and its rejection of them would not show that it was unreasonable in fearing a strike based upon its failure to accede to the unions’ demands.

Finally, the offer of an indefinite extension of the contract is an equally unsupportable basis for the Board’s conclusion. An indefinite extension presumably would mean under traditional contract theory that the unions could *335strike at any time or after giving brief notice.4 Surely the employer would be reasonable in fearing that such an arrangement would peculiarly place the timing of the strike in the unions’ hands.

The sum of all this is that the record does not supply even a scintilla of, let alone any substantial, evidence to support the conclusion of the Board that the employer’s fear of a strike was unreasonable, but, rather, this conclusion appears irrational. Cf. Labor Board v. Erie Resistor Corp., 373 U. S. 221, at 236. I would therefore hold on this record that the employer’s lockout was completely justified.

The fact that the Board held on the undisputed facts that the employer’s fear of a strike was unreasonable and that the Court of Appeals has affirmed the Board does not preclude us from reviewing this determination. See Public Service Comm’n v. United States, 356 U. S. 421. The standard that should have been applied by the Court of Appeals was whether the Board’s finding was supported by substantial evidence when the record was viewed as a whole. Universal Camera Corp. v. Labor Board, 340 U. S. 474. See Burlington Truck Lines, Inc. v. United States, 371 U. S. 156, 168; Interstate Commerce Comm’n v. J-T Transport Co., 368 U. S. 81, 93. “The Board’s findings are entitled to respect; but they must nonetheless be set aside when the record before a Court of Appeals clearly precludes the Board’s decision from being justified by a fair estimate of the worth of the testimony of witnesses or its informed judgment on matters within its special competence or both.” Universal Camera Corp. v. Labor Board, supra, at 490. Indeed, the Board here set aside the report of its trial examiner, and in *336 Universal Camera this Court recognized “that evidence supporting a conclusion may be less substantial when an impartial, experienced examiner who has observed the witnesses and lived with the case has drawn conclusions different from the Board's than when he has reached the same conclusion.” 340 TJ. S., at 496. The Court of Appeals in my view in its summary affirmance on this issue grossly misapplied the standards laid down by Universal Camera. This case is properly before us on a substantial legal question, which necessarily involves a review of the entire record. In making such a review, although we give proper weight to what the first reviewing court decides, we cannot ignore our duty to apply the statutory standard that the Board’s findings must be supported by substantial evidence. Since the Board’s holding was not so supported, but, on the contrary, as the plain facts of the record reveal, was irrational, I would reverse the Court of Appeals on this ground.

My view of this case would make it unnecessary to deal with the broad question of whether an employer may lock out his employees solely to bring economic pressure to bear in support of his bargaining position. The question of which types of lockout are compatible with the labor statute is a complex one as this decision and the other cases decided today illustrate. See Textile Workers Union v. Darlington Mfg. Co., ante, p. 263; Labor Board v. Brown, ante, p. 278. This Court has said that the problem of the legality of certain types of strike activity must be “revealed by unfolding variant situations” and requires “an evolutionary process for its rational response, not a quick, definitive formula as a comprehensive answer.” Electrical Workers v. Labor Board, 366 U. S. 667, 674; see also Labor Board v. Steelworkers, supra, 362-363. The same is true of lockouts.

The types of situation in which an employer might seek to lock out his employees differ considerably one from *337the other. This case presents the situation of an employer with a long history of union recognition and collective bargaining, confronted with a history of past strikes, which locks out only after considerable good-faith negotiation involving agreement and compromise on numerous issues, after a bargaining impasse has been reached, more than a week after the prior contract has expired, and when faced with the threat of a strike at a time when it and the property of its customers can suffer unusual harm. Other cases in which the Board has held a lockout illegal have presented far different situations. For example, in Quaker State Oil Refining Corp., supra, an employer locked out its employees the day after its contract with the union expired although no impasse had been reached in the bargaining still in progress, no strike had been threatened by the unions, which had never called a sudden strike during the 13 years they had bargained with the employer, and the unions had offered to resubmit the employer’s proposals to its employees for a vote. See also Utah Plumbing & Heating Contractors Assn., 126 N. L. R. B. 973. These decisions of the Labor Board properly take into account, in determining the legality of lockouts under the labor statutes, such factors as the length, character, and history of the collective bargaining relation between the union and the employer, as well as whether a bargaining impasse has been reached. Indeed, the Court itself seems to recognize that there is a difference between locking out before a bargaining impasse has been reached and locking out after collective bargaining has been exhausted, for it limits its holding to lockouts in the latter type of situation without deciding the question of the legality of locking out before bargaining is exhausted. Since the examples of different lockout situations could be multiplied, the logic of the Court’s limitation of its holding should lead it to recognize that the problem of lockouts requires “an evolu*338tionary process,” not “a quick, definitive formula,” for its answer.

The Court should be chary of sweeping generalizations in this complex area. When we deal with the lockout and the strike, we are dealing with weapons of industrial warfare. While the parties generally have their choice of economic weapons, see Labor Board v. Insurance Agents, 361 U. S. 477, this choice, with respect to both the strike and the lockout, is not unrestricted. While we have recognized “the deference paid the strike weapon by the federal labor laws,” Labor Board v. Erie Resistor, supra, at 235, not all forms of economically motivated strikes are protected or even permissible under the labor statutes 5 or the prior decisions of this Court.6 Moreover, a lockout prompted by an anti union motive is plainly illegal under the National Labor Relations Act,7 though no similar restrictions as to motive operate to limit the legality of a strike. See Labor Board v. Somerset Shoe Co., 111 F. 2d 681; Labor Board v. Stremel, 141 F. 2d 317 ; Labor Board v. Somerset Classics, Inc., 193 F. 2d 613. The varieties of restrictions imposed upon strikes and lockouts reflect the complexities presented by variant factual situations.

The Court not only overlooks the factual diversity among different types of lockout, but its statement of the rules governing unfair labor practices under §§ 8 (a)(1) and (3) does not give proper recognition to the fact that “[t]he ultimate problem [in this area] is the balancing *339of the conflicting legitimate interests.” Labor Board v. Truck Drivers Union, 353 U. S. 87, 96. The Court states that employer conduct, not actually motivated by anti-union bias,8 does not violate § 8 (a)(1) or § 8 (a)(3) unless it is “demonstrably so destructive of collective bargaining,” ante, at 309, or “so prejudicial to union interests and so devoid of significant economic justification,” ante, at 311, that no antiunion animus need be shown. This rule departs substantially from both the letter and the spirit of numerous prior decisions of the Court. See, e. g., Labor Board v. Truck Drivers Union, supra, at 96; Republic Aviation Corp. v. Labor Board, 324 U. S. 793; Labor Board v. Babcock & Wilcox Co., 351 U. S. 105; Labor Board v. Burnup & Sims, Inc., 379 U. S. 21.

These decisions demonstrate that the correct test for determining whether §8 (a)(1) has been violated in cases not involving an employer antiunion motive is whether the business justification for the employer’s action outweighs the interference with § 7 rights involved. In Republic Aviation Corp. v. Labor Board, supra, for example, the Court affirmed a Board holding that a company “no-solicitation” rule was invalid as applied to prevent solicitation of employees on company property during periods when employees were free to do as they pleased, not because such a rule was “demonstrably . . . destructive of collective bargaining,” but simply because there was no significant employer justification for the rule and there was a showing of union interest, though far short of a necessity, in its abolition. See also, Labor Board v. Burnup & Sims, Inc., supra.

*340A similar test is applicable in § 8 (a) (3) cases where no antiunion motive is shown. The Court misreads Radio Officers v. Labor Board, 347 U. S. 17, and Labor Board v. Erie Resistor Corp., supra, in- stating that the test in such cases under § 8 (a) (3) is whether practices “are inherently so prejudicial to union interests and so devoid of significant economic justification that no specific evidence of intent to discourage union membership or other antiunion animus is required.” Ante, at 311. Radio Officers did not restrict the application of § 8 (a) (3) in cases devoid of antiunion motive to the extreme situations encompassed by the Court's test. Rather, in holding applicable the common-law rule that a man is presumed to intend the foreseeable consequences of his own actions, the Court extended the reach of § 8 (a)(3) to all cases in which a significant antiunion effect is foreseeable regardless of the employer’s motive. In such cases the Court, in Erie Resistor Corp., held that conduct might be determined by the Board to violate § 8 (a) (3) where the Board’s determination resulted from a reasonable “weighing [of] the interests of employees in concerted activity against the interest of the employer in operating his business in a particular manner and . . . [from] balancing in the light of the Act and its policy the intended consequences upon employee rights against the business ends to be served by the employer’s conduct.” 373 U. S., at 229.

These cases show that the tests as to whether an employer’s conduct violates § 8 (a)(1) or violates § 8 (a) (3) without a showing of antiunion motive come down to substantially the same thing: whether the legitimate economic interests of the employer justify his interference with the rights of his employees — a test involving “the balancing of the conflicting legitimate interests.” Labor Board v. Truck Drivers Union, supra, at 96. As the prior decisions of this Court have held, “[t]he function of striking . . . [such a] balance . . . often a difficult and *341delicate responsibility, . . . Congress committed primarily to the National Labor Relations Board, subject to limited judicial review.” Ibid.

This, of course, does not mean that reviewing courts are to abdicate their function of determining whether, giving due deference to the Board, the Board has struck the balance consistently with the language and policy of the Act. See Labor Board v. Brown, supra; Labor Board v. Truck Drivers Union, supra. Nor does it mean that reviewing courts are to rubber-stamp decisions of the Board where the application of principles in a particular case is irrational or not supported by substantial evidence on the record as a whole. Applying these principles to the factual situation here presented, I would accept the Board’s carefully limited rule, fashioned by the Board after weighing the “conflicting legitimate interests” of employers and unions, that a lockout does not violate the Act where used to “safeguard against unusual operational problems or hazards or economic loss where there is reasonable ground for believing that a strike [is] . . . threatened or imminent.” Quaker State Oil Refining Corp., supra, at 337. This rule is consistent with the policies of the Act and based upon the actualities of industrial relations. I would, however, reject the determination of the Board refusing to apply this rule to this case, for the undisputed facts revealed by the record bring this case clearly within the rule.

In view of the necessity for, and the desirability of, weighing the legitimate conflicting interests in variant lockout situations, there is not and cannot be any simple formula which readily demarks the permissible from the impermissible lockout. This being so, I would not reach out in this case to announce principles which are determinative of the legality of all economically motivated lockouts whether before or after a bargaining impasse has *342been reached. In my view both the Court and the Board, in reaching their opposite conclusions, have inadvisably and unnecessarily done so here. Rather, I would confine our decision to the simple holding, supported by both the record and the actualities of industrial relations, that the employer’s fear of a strike was reasonable, and therefore, under the settled decisions of the Board, which I would approve, the lockout of its employees was justified.

MR. Chief Justice Warren

delivered the opinion of the Court.

The issue here is whether, in the absence of proof of an antiunion motivation, an employer may be held to have violated §§ 8 (a)(3) and (1) of the National Labor Relations Act1 when it refused to pay striking employees vacation benefits accrued under a terminated collective bargaining agreement while it announced an intention to pay such benefits to striker replacements, returning strikers, and nonstrikers who had been at work on a certain date during the strike.

*28The respondent company and the union 2 entered into a collective bargaining agreement which was effective by its terms until March 31,1963. The agreement contained a commitment by the company to pay vacation benefits to employees who met certain enumerated qualifications.3 In essence, the company agreed to pay specified vacation *29benefits to employees who, during the preceding year, had worked at least 1,525 hours. It was also provided that, in the case of a “lay-off, termination or quitting,” employees who had served more than 60 days during the year would be entitled to pro rata shares of their vacation benefits. Benefits were to be paid on the Friday nearest July 1 of each year.

The agreement was temporarily extended beyond its termination date, but on April 30, 1963, the union gave the required 15 days’ notice of intention to strike over issues which remained unsettled at the bargaining table. Accordingly, on May 16, 1963, approximately 350 of the company’s 400 employees commenced a strike which lasted until December 26, 1963. The company continued to operate during the strike, using nonstrikers, persons hired as replacements for strikers, and some original strikers who had later abandoned the strike and returned to work.4 On July 12, 1963, a number of the strikers demanded their accrued vacation pay from the company. The company rejected this demand, basing its response on the assertion that all contractual obligations had been terminated by the strike and, therefore, none of the company’s employees had a right to vacation pay. Shortly thereafter, however, the company announced that it would grant vacation pay — in the amounts and subject to the conditions set out in the expired agreement— to all employees who had reported for work on July 1, 1963. The company denied that these payments were founded on the agreement and stated that they merely reflected a new “policy” which had been unilaterally adopted.

*30The refusal to pay vacation benefits to strikers, coupled with the payments to nonstrikers, formed the bases of an unfair labor practice complaint filed with the Board while the strike was still in progress. Violations of §§ 8 (a)(3) and (1) were charged. A hearing was held before a trial examiner who found that the company's action in regard to vacation pay constituted a discrimination in terms and conditions of employment which would discourage union membership, as well as an unlawful interference with protected activity. He held that the company had violated §§ 8 (a)(3) and (1) and recommended that it be ordered to cease and desist from its unfair labor practice and to pay the accrued vacation benefits to strikers. The Board, after reviewing the record, adopted the Trial Examiner’s conclusions and remedy.5

A petition for enforcement of the order was filed in the Court of Appeals for the Fifth Circuit. That court first dealt with the company’s contention that the Board had lacked jurisdiction and that the union should have been relegated either to the bargaining table or to a lawsuit under § 301 of the Act,6 since the basic question was one of contract interpretation and application. It noted that the company’s announced policy relating to vacation pay clearly concerned a “term or condition of employment”; since it was alleged that the company had discriminated between striking and nonstriking employees in regard to that term or condition of employment, the complaint stated “an unfair labor practice charge in simplest terms” and the Board had properly exercised its jurisdiction.7 *31Reviewing the substantive aspects of the Board's decision next, the Court of Appeals held that, although discrimination between striking and nonstriking employees had been proved, the Board’s conclusion that the company had committed an unfair labor practice was not well-founded inasmuch as there had been no affirmative showing of an unlawful motivation to discourage union membership or to interfere with the exercise of protected rights. Despite the fact that the company itself had not introduced evidence of a legitimate business purpose underlying its discriminatory action, the Court of Appeals speculated that it might have been motivated by a desire “(1) to reduce expenses; (2) to encourage longer tenure among present employees; or (3) to discourage early leaves immediately before vacation periods.” Believing that the possibility of the existence of such motives was sufficient to overcome the inference of an improper motive which flowed from the conduct itself, the court denied enforcement of the order. 363 F. 2d 130 (1966). We granted certiorari to determine whether the treatment of the motivation issue by the Court of Appeals was consistent with recent decisions of this Court. 385 U. S.. 1000 (1967).

*32The unfair labor practice charged here is grounded primarily in §8 (a) (3) which requires specifically that the Board find a discrimination and a resulting discouragement of union membership. American Ship Building Co. v. Labor Board, 380 U. S. 300, 311 (1965). There is little question but that the result of the company’s refusal to pay vacation benefits to strikers was discrimination in its simplest form. Compare Republic Aviation Corp. v. Labor Board, 324 U. S. 793 (1945), with Teamsters Union v. Labor Board, 365 U. S. 667 (1961). Some employees who met the conditions specified in the expired collective bargaining agreement were paid accrued vacation benefits in the amounts set forth in that agreement, while other employees8 who also met the conditions but who had engaged in protected concerted activity were denied such benefits. Similarly, there can be no doubt but that the discrimination was capable of discouraging membership in a labor organization within the meaning of the statute. Discouraging membership in a labor organization “includes discouraging participation in concerted activities . . . such as a legitimate strike.” Labor Board v. Erie Resistor Corp., 373 U. S. 221, 233 (1963). The act of paying accrued benefits to one group of employees while announcing the extinction of the same benefits for another group of employees who are distinguishable only by their participation in protected concerted activity surely may have a discouraging effect on either present or future concerted activity.

*33But inquiry under § 8 (a) (3) does not usually stop at this point. The statutory language “discrimination . . . to . . . discourage” means that the finding of a violation normally turns on whether the discriminatory conduct was motivated by an antiunion purpose. American Ship Building Co. v. Labor Board, 380 U. S. 300 (1965). It was upon the motivation element that the Court of Appeals based its decision not to grant enforcement, and it is to that element which we now turn. In three recent opinions we considered employer motivation in the context of asserted § 8 (a) (3) violations. American Ship Building Co. v. Labor Board, supra; Labor Board v. Brown, 380 U. S. 278 (1965); and Labor Board v. Erie Resistor Corp., supra. We noted in Erie Resistor, supra, at 227, that proof of an antiunion motivation may make unlawful certain employer conduct which would in other circumstances be lawful. Some conduct, however, is so “inherently destructive of employee interests” that it may be deemed proscribed without need for proof of an underlying improper motive. Labor Board v. Brown, supra, at 287; American Ship Building Co. v. Labor Board, supra, at 311. That is, some conduct carries with it “unavoidable consequences which the employer not only foresaw but which he must have intended” and thus bears “its own indicia of intent.” Labor Board v. Erie Resistor Corp., supra, at 228, 231. If the conduct in question falls within this “inherently destructive” category, the employer has the burden of explaining away, justifying or characterizing “his actions as something different than they appear on their face,” and if he fails, “an unfair labor practice charge is made out.” Id., at 228. And even if the employer does come forward with counter explanations for his conduct in this situation, the Board may nevertheless draw an inference of improper motive from the conduct itself and exercise its duty to strike the proper balance between the asserted *34business justifications and the invasion of employee rights in light of the Act and its policy. Id., at 229. On the other hand, when “the resulting harm to employee rights is . . . comparatively slight, and a substantial and legitimate business end is served, the employers’ conduct is prima facie lawful,” and an affirmative showing of improper motivation must be made. Labor Board v. Brown, supra, at 289; American Ship Building Co. v. Labor Board, supra, at 311-313.

From this review of our recent decisions, several principles of controlling importance here can be distilled. First, if it can reasonably be concluded that the employer’s discriminatory conduct was “inherently destructive” of important employee rights, no proof of an anti-union motivation is needed and the Board can find an unfair labor practice even if the employer introduces evidence that the conduct was motivated by business considerations. Second, if the adverse effect of the discriminatory conduct on employee rights is “comparatively slight,” an antiunion motivation must be proved to sustain the charge if the employer has come forward with evidence of legitimate and substantial business justifications for the conduct. Thus, in either situation, once it has been proved that the employer engaged in discriminatory conduct which could have adversely affected employee rights to some extent, the burden is upon the employer to establish that he was motivated by legitimate objectives since proof of motivation is most accessible to him.

Applying the principles to this case then, it is not necessary for us to decide the degree to which the challenged conduct might have affected employee rights. As the Court of Appeals correctly noted, the company came forward with no evidence of legitimate motives for its discriminatory conduct. 363 F. 2d, at 134. The company simply did not meet the burden of proof, and *35the Court of Appeals misconstrued the function of judicial review when it proceeded nonetheless to speculate upon what might have motivated the company. Since discriminatory conduct carrying a potential for adverse effect upon employee rights was proved and no evidence of a proper motivation appeared in the record, the Board’s conclusions were supported by substantial evidence, Universal Camera Corp. v. Labor Board, 340 U. S. 474 (1951), and should have been sustained.

The judgment of the Court of Appeals is reversed and the case is remanded with directions to enforce the Board’s order.

It is so ordered.

Me. Justice Harlan,

whom Mr. Justice Stewart joins,

dissenting.

Because I think that the Court puts forth a premise which misinterprets the recent decision in NLRB v. C & C Plywood Corp., 385 U. S. 421, and has proposed a determining rule based on a distillation of prior opinions which is, in my view, substantially inaccurate, I am constrained to express my dissent from its opinion. I believe that the Fifth Circuit correctly analyzed the problem, and that its decision should be affirmed.

The Court begins by stating that vacation benefits had “accrued” under the contract, and implies that striking employees had a contractual right to such benefits which was arbitrarily disregarded by Great Dane in order to punish those employees for engaging in protected activity. Were these the properly established facts of the case, I would have little difficulty in concurring in the result reached by the majority. Employer action which undercuts rights protected by § 7 of the National Labor Relations Act, as amended, 61 Stat. 140, and has no inferable, legitimate business purpose has been held a violation of §§ 8 (a)(3) and (1). Republic Aviation *36 Corp. v. Labor Board, 324 U. S. 793. But the contract dispute is not so frivolous as to be determined without examination,1 and the issue framed by the Court is not properly before us. Moreover, contrary to the Court’s assertion, neither the Board nor the lower court limited itself to considering this issue, and both recognized a limitation on the Board’s contract interpretation powers in light of § 301 (a) of the Labor Management Relations Act, 1947.2

The Board disclaimed “interpreting the contract for the parties” and held only that “strikers must be treated uniformly with nonstrikers with respect to whatever benefits accrue to the latter from the existence of the employment relationship.” It explained that its order would merely force the employer to use the same vacation pay criteria for all employees and only prevent Great Dane from using the requirement that a recipient be at work as of July 1, 1963. The Court of Appeals considered the “term or condition of employment” at issue to be the employer’s unilaterally declared vacation “policy.” It explicitly disregarded “the question of whether the Board would have acted improperly . . . to decide whether it was an unfair labor practice to withhold benefits due under the contract . . . .” 363 F. 2d 130, 133. (Emphasis in original.)

*37I think the Board and the Court of Appeals were correct in disregarding the contract issue. In NLRB v. C & C Plywood Corp., supra, which the Court says upholds jurisdiction to consider the contract, we faced a situation in which an employer had taken a unilateral action with respect to wages which was a prima facie violation of § 8 (a) (3) and was attempting to justify that action by contractual privilege. The Court held that the interposition of a contractual defense could not deprive the Board of jurisdiction to “enforce a statutory right” where the Board had “not construed a labor agreement to determine the extent of the contractual rights which were given the union by the employer.” Id., at 428. Also the agreement involved in that case did not contain an arbitration clause and thus the strong policy favoring arbitration was not infringed by the Board’s action. Id., at 426. Here the Court’s statement of the issue would imply that the Board may consider an unfair labor practice founded solely on breach of a contractual duty, and the labor agreement seems to invoke the remedy of arbitration.3 In these circumstances, I think the. only issue properly before the Court is whether the employer’s unilaterally declared vacation policy, considered on its own bottom, constitutes a violation of § 8 (a) (3) absent a showing of improper motivation by evidence independent of the policy itself.

The Court attempts to resolve this issue as well as the contractual one. In the Court’s view an employer must “come forward with evidence of legitimate and substantial business justifications” whenever any of his actions are challenged in a § 8 (a) (3) proceeding. Prior to *38today’s decision, § 8 (a) (3) violations could be grouped into two general categories: those based on actions serving no legitimate business purposes or actions inherently severely destructive of employee rights where improper motive could be inferred from the actions themselves, and, in the latter instance, even a legitimate business purpose could be held by the Board not to justify the employer’s conduct, Labor Board v. Erie Resistor Corp., 373 U. S. 221; and those not based on actions “demonstrably so destructive of employee rights and so devoid of significant service to any legitimate business end,” where independent evidence evincing the employer’s anti-union animus would be required to find a violation. Labor Board v. Brown, 380 U. S. 278, 286. The Court is unable to conclude that the employer’s conduct in this case falls into the first category, and has proposed its rule as an added gloss on the second whose contours were fixed only two years ago in Brown.

Under today’s formulation, the Board is required to find independent evidence of the employer’s antiunion motive only when the employer has overcome the presumption of unlawful motive which the Court raises. This alteration of the burden in §8 (a) (3) cases may either be a rule of convenience important to the resolution of this case alone or may, more unfortunately, portend an important shift in the manner of deciding employer unfair labor practice cases under §8 (a)(3). In either event, I believe it is unwise.

The “legitimate and substantial business justifications” test may be interpreted as requiring only that the employer come forward with a nonfrivolous business purpose in order to make operative the usual requirement of proof of antiunion motive. If this is the result of today’s decision, then the Court has merely penalized Great Dane for not anticipating this requirement when arguing before the Board. Such a penalty seems par*39ticularly unfair in view of the clarity of our recent pronouncements that “the Board must find from evidence independent of the mere conduct involved that the conduct was primarily motivated by an antiunion animus/’ Labor Board v. Brown, 380 U. S., at 288, and that “the Board must find that the employer acted for a proscribed purpose.” American Ship Building Co. v. Labor Board, 380 U. S. 300, 313.

On the other hand, the use of the word “substantial” in the burden of proof formulation may give the Board a power which it formerly had only in § 8 (a)(3) cases like Erie Resistor, supra. The Board may seize upon that term to evaluate the merits of the employer’s business purposes and weigh them against the harm that befalls the union’s interests as a result of the employer’s action. If this is the Court’s meaning, it may well impinge upon the accepted principle that “the right to bargain collectively does not entail any ‘right’ to insist on one’s position free from economic disadvantage.” American Ship Building Co. v. Labor Board, supra, at 309. Employers have always been free to take reasonable measures which discourage a strike by pressuring the economic interests of employees, including the extreme measure of hiring permanent replacements, without having the Board inquire into the “substantiality” of their business justifications. Labor Board v. Mackay Radio & Telegraph Co., 304 U. S. 333. If the Court means to change this rule, though I assume it does not, it surely should not do so without argument of the point by the parties and without careful discussion.

In my opinion, the Court of Appeals correctly held that this case fell into the category in which independent evidence of antiunion motive is required to sustain a violation. As was pointed out in the Court of Appeals opinion, a number of legitimate motives for the terms of the vacation policy could be inferred, 363 F. 2d, at 134, *40and an unlawful motive is not the sole inference to be drawn from the conduct. Nor is the employer’s conduct here, like the super-seniority plan in Erie Resistor, supra, such that an unlawful motive can be found by “an application of the common-law rule that a man is held to intend the foreseeable consequences of his conduct.” Radio Officers v. Labor Board, 347 U. S. 17, 45. The differences between the facts of this case and those of Erie Resistor, supra, are, as the parties recognize, so significant as to preclude analogy. Unlike the granting-of super-seniority, the vacation pay policy here had no potential long-term impact on the bargaining situation. The vacation policy was not employed as a weapon against the strike as was the super-seniority plan. Notice of the date of required presence for vacation pay eligibility was not given until after the date had passed. The record shows clearly that Great Dane had no need to employ any such policy to combat the strike, since it had successfully replaced almost all of the striking employees.4 The Trial Examiner rejected all union claims that particular actions by Great Dane demonstrated antiunion animus. In these circumstances, the Court of Appeals correctly found no substantial evidence of a violation of §8 (a) (3).

Plainly the Court is concerned lest the strikers in this case be denied their “rights” under the collective bargaining agreement that expired at the commencement of the strike. Equally plainly, a suit under § 301 is the proper manner by which to secure these “rights,” if they indeed exist. I think it inappropriate to becloud sound prior interpretations of § 8 (a) (3) simply to reach what seems a sympathetic result.