opinion: Mr. Justice Brennan
  delivered the opinion of the Court.
  The question presented by this case is whether the non-struck members of a multi-employer bargaining association committed an unfair labor practice when, during contract negotiations, they temporarily locked out their employees as a defense to a union strike against one of their members which imperiled the employers’ common interest in bargaining on a group basis.
  The National Labor Relations Board determined that resort to the temporary lockout was not an unfair labor practice in the circumstances. The Court of Appeals for the Second Circuit reversed. This Court granted certio-rari to consider this important question of the construction of the amended National Labor Relations Act, and also to consider an alleged conflict with decisions of Courts of Appeals of other circuits.
  Eight employers in the linen supply business in and around Buffalo, New York, comprise the membership of the Linen and Credit Exchange. For approximately 13 years, the Exchange and the respondent Union, representing the truck drivers employed by the members, bargained on a multi-employer basis and negotiated successive collective bargaining agreements signed by the Union and by the eight employers. Sixty days before such an agreement was to expire on April 30, 1953, the Union gave notice of its desire to open negotiations for changes.
  The Exchange and the Union began negotiations some time before April 30, but the negotiations carried past that date and were continuing on May 26, 1953, when the Union put into effect a “whipsawing” plan by striking and picketing the plant of one of the Exchange members, Frontier Linen Supply, Inc. The next day, May 27, the remaining seven Exchange members laid off their truck drivers after notifying the Union that the layoff action was taken because of the Frontier strike, advising the Union that the laid-off drivers would be recalled if the Union withdrew its picket line and ended the strike. Negotiations continued without interruption, however, until a week later when agreement was reached upon a new contract which the Exchange members and the Union approved and signed. Thereupon the Frontier strike was ended, the laid-off drivers were recalled, and normal operations were resumed at the plants of all Exchange members.
  The Union filed with the National Labor Relations Board an unfair labor practice charge against the seven employers, alleging that the temporary lockout interfered with its rights guaranteed by § 7, thereby violating §§ 8 (a)(1) and (3) of the Act. A complaint issued, and, after hearing, a trial examiner found the employers guilty of the unfair labor practice charged. The Board overruled the trial examiner, finding that “the more reasonable inference is that, although not specifically-announced by the Union, the strike against the one employer necessarily carried with it an implicit threat of future strike action against any or all of the other members of the Association,” with the “calculated purpose” of causing “successive and individual employer capitulations.” The Board therefore found that “in the absence of any independent evidence of antiunion motivation, . . . the Respondent’s [sic] action in shutting their plants until termination of the strike at Frontier was defensive and privileged in nature, rather than retaliatory and unlawful.” The Board, citing Leonard v. Labor Board, 205 F. 2d 355, concluded “that a strike by employees against one employer-member of a multiemployer bargaining unit constitutes a threat of strike action against the other employers, which threat, per se, constitutes the type of economic or operative problem at the plants of the nonstruck employers which legally justifies their resort to a temporary lockout of employees.”
  The Court of Appeals agreed “that the Board reasonably inferred” a threat of strike action against the seven employers because there were “no peculiar facts concerning the Union’s relations with that single member.” The Court of Appeals thus implicitly found that the only reason for the strike against Frontier was the refusal of the Exchange to meet the Union’s demands. But the court held that a temporary lockout of employees on a “mere threat of, or in anticipation of, a strike” could be justified only if there were unusual economic hardship, and because “the stipulated facts show no economic justification for the lockout, . . . the lockout of non-striking employees constituted an interference with their statutory right to engage in concerted activity in violation of § 8 (a)(1) of the Act, and also constituted discrimination in the hire and tenure of employment of the employees because of the Union’s action, thereby discouraging membership in the Union in violation of § 8 (a) (3) of the Act.”
  Although, as the Court of Appeals correctly noted, there is no express provision in the law either prohibiting or authorizing the lockout, the Act does not make the lockout unlawful per se. Legislative history of the Wagner Act, 49 Stat. 449, indicates that there was no intent to prohibit strikes or lockouts as such. The unqualified use of the term “lock-out” in several sections of the Taft-Hartley Act is statutory recognition that there are circumstances in which employers may lawfully resort to the lockout as an economic weapon. This conclusion is supported by the legislative history of the Act.
  We are not concerned here with the cases in which the lockout has been held unlawful because designed to frustrate organizational efforts, to destroy or undermine bargaining representation, or to evade the duty to bargain. Nor are we called upon to define the limits of the legitimate use of the lockout. The narrow question to be decided is whether a temporary lockout may lawfully be used as a defense to a union strike tactic which threatens the destruction of the employers’ interest in bargaining on a group basis.
  The Court of Appeals rejected the preservation of the integrity of the multi-employer bargaining unit as a justification for an employer lockout. The court founded this conclusion upon its interpretation of the Taft-Hart-ley Act and its legislative history. After stating that “ [m] ulti-employer bargaining has never received the express sanction of Congress,” the court reasoned that because at the time of the enactment of the Taft-Hartley Act the Board had never “gone to the extreme lengths to which it now seeks to go in order to maintain the ‘stability of the employer unit/ ” Congress cannot be said to have given legislative approval to the present Board action. The court concluded that “Congress must have intended that such a radical innovation be left open for consideration by the joint committee it set up under § 402 of the Act to study, among other things, ‘the methods and procedures for best carrying out the collective-bargaining processes, with special attention to the effects of industry-wide or regional bargaining upon the national economy.’ ”
  We cannot subscribe to this interpretation. Multi-employer bargaining long antedated the Wagner Act, both in industries like the garment industry, characterized by numerous employers of small work forces, and in industries like longshoring and building construction, where workers change employers from day to day or week to week. This basis of bargaining has had its greatest expansion since enactment of the Wagner Act because employers have sought through group bargaining to match increased union strength. "Approximately four million employees are now governed by collective bargaining agreements signed by unions with thousands of employer associations. At the time of the debates on the Taft-Hartley amendments, proposals were made to limit or outlaw multi-employer bargaining. These proposals failed of enactment. They were met with a storm of protest that their adoption would tend to weaken and not strengthen the process of collective bargaining and would conflict with the national labor policy of promoting industrial peace through effective collective bargaining.
  The debates over the proposals demonstrate that Congress refused to interfere with such bargaining because there was cogent evidence that in many industries the multi-employer bargaining basis was a vital factor in the effectuation of the national policy of promoting labor peace through strengthened collective bargaining. The inaction of Congress with respect to multi-employer bargaining cannot be said to indicate an intention to leave the resolution of this problem to future legislation. Rather, the compelling conclusion is that Congress intended “that the Board should continue its established administrative practice of certifying multi-employer units, and intended to leave to the Board's specialized judgment the inevitable questions concerning multi-employer bargaining bound to arise in the future.”
  Although the Act protects the right of the employees to strike in support of their demands, this protection is not so absolute as to deny self-help by employers when legitimate interests of employees and employers collide. Conflict may arise, for example, between the right to strike and the interest of small employers in preserving multi-employer bargaining as a means of bargaining on an equal basis with a large union and avoiding the competitive disadvantages resulting from nonuniform contractual terms. 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.
  The Court of Appeals recognized that the National Labor Relations Board has legitimately balanced conflicting interests by permitting lockouts where economic hardship was shown. The court erred, however, in too narrowly confining the exercise of Board discretion to the cases of economic hardship. We hold that in the circumstances of this case the Board correctly balanced the conflicting interests in deciding that a temporary lockout to preserve the multi-employer bargaining basis from the disintegration threatened by the Union’s strike action was lawful.
  Reversed.
  MR. Justice Whittaker took no part in the consideration or decision of this case.
  109 N. L. R. B. 447.
  231 F. 2d 110.
  352 U. S. 818.
  61 Stat. 136, 29 ü. S. C. § 141 et seq.
  Labor Board v. Continental Baking Co., 221 F. 2d 427 (C. A. 8th Cir.); Labor Board v. Spalding Avery Lumber Co., 220 F. 2d 673 (C. A. 8th Cir.); Leonard v. Labor Board, 197 F. 2d 435, 205 F. 2d 355 (C. A. 9th Cir.); Morand Bros. Beverage Co. v. Labor Board, 190 F. 2d 576 (C. A. 7th Cir.).
  The contract contained an automatic renewal clause requiring notice of a desire to change the contract to be given 60 days before the expiration date. The notice was also in conformity with § 8 (d) of the Act. 61 Stat. 140, 29 U. S. C. § 158.
  “Whipsawing” is the process of striking one at a time the employer members of a multi-employer association.
  Section 7 provides in pertinent part:
  “Employees shall have the right to self-organization, to form, join, or assist labor organizations, to bargain collectively through representatives of their own choosing, and to engage in other concerted activities for the purpose of collective bargaining or other mutual aid or protection 61 Stat. 140, 29 U. S. C. § 157.
  Section 8 provides in pertinent part:
  “ (a) It shall be an unfair labor practice for an employer—
  “(1) to interfere with, restrain, or coerce employees in the exercise of the rights guaranteed in section 7;
  “(3) by discrimination in regard to hire or tenure of employment or any term or condition of employment to encourage or discourage membership in any labor organization 61 Stat. 140, 29 U. S. C. § 158.
  109 N. L. R. B., at 448.
  109 N. L. R. B., at 448. The Board relied upon the decision of the Court of Appeals for the Ninth Circuit in Leonard v. Labor Board, 205 F. 2d 355, 357-358, wherein the court stated: “. . . the right of the employers to lock out temporarily all the employees is no more than equal to the right of the union of all the employees to call out the employees of one after another of the . . . [employers] in the whipsawing manner
  109 N. L. R. B., at 448-449.
  231 F. 2d, at 112.
  Id., at 113.
  Id., at 118.
  See, e. g., explanation of the bill by Senator Walsh, Chairman of the Senate Committee on Education and Labor, 79 Cong. Rec. 7673.
  61 Stat. 140, 29 U. S. C. § 158 (d) (4) (no resort to “strike or lock-out” during 60-day notice period); 61 Stat. 153, 29 U. S. C. § 173 (c) (Director of Mediation Service to seek to induce parties to settle dispute peacefully “without resort to strike, lock-out, or other coercion”); 61 Stat. 155, 29 U. S. C. § 176 (appointment of board of inquiry by President when “threatened or actual strike or lock-out” creates a national emergéncy); 61 Stat. 155, 29 U. S. C. § 178 (power to enjoin “strike or lock-out” in case of national emergency).
  H. R. Rep. No. 245, 80th Cong., 1st Sess. 21-22, 70, 82; S. Rep. No. 105, 80th Cong., 1st Sess. 24; S. Rep. No. 105, Pt. 2, 80th Cong., 1st Sess. 21; H. R. Conf. Rep. No. 510, 80th Cong., 1st Sess. 34-35. See also, e. g., 93 Cong. Rec. 1827-1828, 3835.
  E. g., Labor Board v. Wallick, 198 F. 2d 477; Labor Board v. Somerset Classics, 193 F. 2d 613; Olin Industries v. Labor Board, 191 F. 2d 613; cf. Associated Press v. Labor Board, 301 U. S. 103.
  We thus find it unnecessary to pass upon the question whether, as a general proposition, the employer lockout is the corollary of the employees’ statutory right to strike.
  As previously noted, the Board decision is based in part on a finding that the preservation of employer solidarity justifies a lockout as a defense to a whipsaw strike.
  231 F. 2d, at 117-118.
  Id., at 118.
  The opinion of the Court of Appeals may be interpreted as rejecting employer solidarity as a justification for a lockout on the ground that the Union strike constituted a withdrawal by the Union from the multi-employer bargaining unit. The Court of Appeals vigorously argued that a union should be accorded the same freedom of voluntary withdrawal from a multi-employer bargaining unit as the Board has accorded to individual employers. But that question is not presented by this case, and we expressly reserve decision until it is properly before us. The facts here clearly show that the Union strike was not an attempt to withdraw from the multi-employer bargaining unit. On the contrary, the Union continued to carry on negotiations with the Exchange until an agreement was reached and signed.
  Bahrs, The San Francisco Employers’ Council; Chamberlain, Collective Bargaining, 178-179, 180, 182; Freidin, The Taft-Hartley Act and Multi-Employer Bargaining, 4-5; Garrett and Tripp, Management Problems Implicit In Multi-Employer Bargaining, 2-3; Kerr and Randall, Collective Bargaining in the Pacific Coast Pulp and Paper Industry, 3-4; Pierson, Multi-Employer Bargaining, 35-36; Wolman, Industry-Wide Bargaining.
  79 Monthly Labor Review 805 (1956).
  Based on collective bargaining agreements on file with the Bureau of Labor Statistics in 1951, approximately 80% of the unionized employees in the laundry industry were represented under multi-employer bargaining. B. L. S. Rep. No. 1 (1953), Collective Bargaining Structures: The Employer Bargaining Unit, 10.
  Hearings before Senate Committee on Labor and Public Welfare on S. 55 et al., 80th Cong., 1st Sess. 427-428, 1012-1017, 1032-1037, 1055-1057, 1162-1165, 2018-2019, 2370-2371; S. Rep. No. 105, pt. 2, 80th Cong., 1st Sess. 6-8; Hearings before House Committee on Education and Labor on H. R. 8 et al., 80th Cong., 1st Sess. 552-553, 1552-1554, 3024-3026; 93 Cong. Rec. 1834-1844, 4030-4031, 4443-4444, 4581-4587, 4674-4676.
  231 F. 2d, at 121 (dissenting opinion).
  Labor Board v. Mackay Radio & Telegraph Co., 304 U. S. 333; Labor Board v. Continental Baking Co., 221 F. 2d 427; Labor Board v. Spalding Avery Lumber Co., 220 F. 2d 673; Leonard v. Labor Board, 197 F. 2d 435, 205 F. 2d 355; Morand Bros. Beverage Co. v. Labor Board, 190 F. 2d 576; Betts Cadillac Olds, Inc., 96 N. L. R. B. 268; International Shoe Co., 93 N. L. R. B. 907; Duluth Bottling Association, 48 N. L. R. B. 1335.
  Labor Board v. Babcock & Wilcox Co., 351 U. S. 105; Republic Aviation Corp. v. Labor Board, 324 U. S. 793; Phelps Dodge Corp. v. Labor Board, 313 U. S. 177.
  In Phelps Dodge, the Court said:
  "... There is an area plainly covered by the language of the Act and an area no less plainly without it. But in the nature of things Congress could not catalogue all the devices and stratagems for circumventing the policies of the Act. Nor could it define the whole gamut of remedies to effectuate these policies in an infinite variety of specific situations. Congress met these difficulties by leaving the adaptation of means to end to the empiric process of administration. The exercise of the process was committed to the Board, subject to limited judicial review. Because the relation of remedy to policy is peculiarly a matter for administrative competence, courts must not enter the allowable area of the Board’s discretion and must guard against the danger of sliding unconsciously from the narrow confines of law into the more spacious domain of policy. On the other hand, the power with which Congress invested the Board implies responsibility — the responsibility of exercising its judgment in employing the statutory powers.” 313 U. S., at 194.
  Betts Cadillac Olds, Inc., 96 N. L. R. B. 268; International Shoe Co., 93 N. L. R. B. 907; Duluth Bottling Association, 48 N. L. R. B. 1335.
choices: attorney general of the United States, or his office specified state board or department of education city, town, township, village, or borough government or governmental unit state commission, board, committee, or authority county government or county governmental unit, except school district court or judicial district state department or agency governmental employee or job applicant female governmental employee or job applicant minority governmental employee or job applicant minority female governmental employee or job applicant not listed among agencies in the first Administrative Action variable retired or former governmental employee U.S. House of Representatives interstate compact judge state legislature, house, or committee local governmental unit other than a county, city, town, township, village, or borough governmental official, or an official of an agency established under an interstate compact state or U.S. supreme court local school district or board of education U.S. Senate U.S. senator foreign nation or instrumentality state or local governmental taxpayer, or executor of the estate of state college or university United States State person accused, indicted, or suspected of crime advertising business or agency agent, fiduciary, trustee, or executor airplane manufacturer, or manufacturer of parts of airplanes airline distributor, importer, or exporter of alcoholic beverages alien, person subject to a denaturalization proceeding, or one whose citizenship is revoked American Medical Association National Railroad Passenger Corp. amusement establishment, or recreational facility arrested person, or pretrial detainee attorney, or person acting as such;includes bar applicant or law student, or law firm or bar association author, copyright holder bank, savings and loan, credit union, investment company bankrupt person or business, or business in reorganization establishment serving liquor by the glass, or package liquor store water transportation, stevedore bookstore, newsstand, printer, bindery, purveyor or distributor of books or magazines brewery, distillery broker, stock exchange, investment or securities firm construction industry bus or motorized passenger transportation vehicle business, corporation buyer, purchaser cable TV car dealer person convicted of crime tangible property, other than real estate, including contraband chemical company child, children, including adopted or illegitimate religious organization, institution, or person private club or facility coal company or coal mine operator computer business or manufacturer, hardware or software consumer, consumer organization creditor, including institution appearing as such; e.g., a finance company person allegedly criminally insane or mentally incompetent to stand trial defendant debtor real estate developer disabled person or disability benefit claimant distributor person subject to selective service, including conscientious objector drug manufacturer druggist, pharmacist, pharmacy employee, or job applicant, including beneficiaries of employer-employee trust agreement, employee health and welfare fund, or multi-employer pension plan electric equipment manufacturer electric or hydroelectric power utility, power cooperative, or gas and electric company eleemosynary institution or person environmental organization employer. If employer's relations with employees are governed by the nature of the employer's business (e.g., railroad, boat), rather than labor law generally, the more specific designation is used in place of Employer. farmer, farm worker, or farm organization father female employee or job applicant female movie, play, pictorial representation, theatrical production, actor, or exhibitor or distributor of fisherman or fishing company food, meat packing, or processing company, stockyard foreign (non-American) nongovernmental entity franchiser franchisee lesbian, gay, bisexual, transexual person or organization person who guarantees another's obligations handicapped individual, or organization of devoted to health organization or person, nursing home, medical clinic or laboratory, chiropractor heir, or beneficiary, or person so claiming to be hospital, medical center husband, or ex-husband involuntarily committed mental patient Indian, including Indian tribe or nation insurance company, or surety inventor, patent assigner, trademark owner or holder investor injured person or legal entity, nonphysically and non-employment related juvenile government contractor holder of a license or permit, or applicant therefor magazine male medical or Medicaid claimant medical supply or manufacturing co. racial or ethnic minority employee or job applicant minority female employee or job applicant manufacturer management, executive officer, or director, of business entity military personnel, or dependent of, including reservist mining company or miner, excluding coal, oil, or pipeline company mother auto manufacturer newspaper, newsletter, journal of opinion, news service radio and television network, except cable tv nonprofit organization or business nonresident nuclear power plant or facility owner, landlord, or claimant to ownership, fee interest, or possession of land as well as chattels shareholders to whom a tender offer is made tender offer oil company, or natural gas producer elderly person, or organization dedicated to the elderly out of state noncriminal defendant political action committee parent or parents parking lot or service patient of a health professional telephone, telecommunications, or telegraph company physician, MD or DO, dentist, or medical society public interest organization physically injured person, including wrongful death, who is not an employee pipe line company package, luggage, container political candidate, activist, committee, party, party member, organization, or elected official indigent, needy, welfare recipient indigent defendant private person prisoner, inmate of penal institution professional organization, business, or person probationer, or parolee protester, demonstrator, picketer or pamphleteer (non-employment related), or non-indigent loiterer public utility publisher, publishing company radio station racial or ethnic minority person or organization protesting racial or ethnic segregation or discrimination racial or ethnic minority student or applicant for admission to an educational institution realtor journalist, columnist, member of the news media resident restaurant, food vendor retarded person, or mental incompetent retired or former employee railroad private school, college, or university seller or vendor shipper, including importer and exporter shopping center, mall spouse, or former spouse stockholder, shareholder, or bondholder retail business or outlet student, or applicant for admission to an educational institution taxpayer or executor of taxpayer's estate, federal only tenant or lessee theater, studio forest products, lumber, or logging company person traveling or wishing to travel abroad, or overseas travel agent trucking company, or motor carrier television station union member unemployed person or unemployment compensation applicant or claimant union, labor organization, or official of veteran voter, prospective voter, elector, or a nonelective official seeking reapportionment or redistricting of legislative districts (POL) wholesale trade wife, or ex-wife witness, or person under subpoena network slave slave-owner bank of the united states timber company u.s. job applicants or employees Army and Air Force Exchange Service Atomic Energy Commission Secretary or administrative unit or personnel of the U.S. Air Force Department or Secretary of Agriculture Alien Property Custodian Secretary or administrative unit or personnel of the U.S. Army Board of Immigration Appeals Bureau of Indian Affairs Bonneville Power Administration Benefits Review Board Civil Aeronautics Board Bureau of the Census Central Intelligence Agency Commodity Futures Trading Commission Department or Secretary of Commerce Comptroller of Currency Consumer Product Safety Commission Civil Rights Commission Civil Service Commission, U.S. Customs Service or Commissioner of Customs Defense Base Closure and REalignment Commission Drug Enforcement Agency Department or Secretary of Defense (and Department or Secretary of War) Department or Secretary of Energy Department or Secretary of the Interior Department of Justice or Attorney General Department or Secretary of State Department or Secretary of Transportation Department or Secretary of Education U.S. Employees' Compensation Commission, or Commissioner Equal Employment Opportunity Commission Environmental Protection Agency or Administrator Federal Aviation Agency or Administration Federal Bureau of Investigation or Director Federal Bureau of Prisons Farm Credit Administration Federal Communications Commission (including a predecessor, Federal Radio Commission) Federal Credit Union Administration Food and Drug Administration Federal Deposit Insurance Corporation Federal Energy Administration Federal Election Commission Federal Energy Regulatory Commission Federal Housing Administration Federal Home Loan Bank Board Federal Labor Relations Authority Federal Maritime Board Federal Maritime Commission Farmers Home Administration Federal Parole Board Federal Power Commission Federal Railroad Administration Federal Reserve Board of Governors Federal Reserve System Federal Savings and Loan Insurance Corporation Federal Trade Commission Federal Works Administration, or Administrator General Accounting Office Comptroller General General Services Administration Department or Secretary of Health, Education and Welfare Department or Secretary of Health and Human Services Department or Secretary of Housing and Urban Development Interstate Commerce Commission Indian Claims Commission Immigration and Naturalization Service, or Director of, or District Director of, or Immigration and Naturalization Enforcement Internal Revenue Service, Collector, Commissioner, or District Director of Information Security Oversight Office Department or Secretary of Labor Loyalty Review Board Legal Services Corporation Merit Systems Protection Board Multistate Tax Commission National Aeronautics and Space Administration Secretary or administrative unit of the U.S. Navy National Credit Union Administration National Endowment for the Arts National Enforcement Commission National Highway Traffic Safety Administration National Labor Relations Board, or regional office or officer National Mediation Board National Railroad Adjustment Board Nuclear Regulatory Commission National Security Agency Office of Economic Opportunity Office of Management and Budget Office of Price Administration, or Price Administrator Office of Personnel Management Occupational Safety and Health Administration Occupational Safety and Health Review Commission Office of Workers' Compensation Programs Patent Office, or Commissioner of, or Board of Appeals of Pay Board (established under the Economic Stabilization Act of 1970) Pension Benefit Guaranty Corporation U.S. Public Health Service Postal Rate Commission Provider Reimbursement Review Board Renegotiation Board Railroad Adjustment Board Railroad Retirement Board Subversive Activities Control Board Small Business Administration Securities and Exchange Commission Social Security Administration or Commissioner Selective Service System Department or Secretary of the Treasury Tennessee Valley Authority United States Forest Service United States Parole Commission Postal Service and Post Office, or Postmaster General, or Postmaster United States Sentencing Commission Veterans' Administration War Production Board Wage Stabilization Board General Land Office of Commissioners Transportation Security Administration Surface Transportation Board U.S. Shipping Board Emergency Fleet Corp. Reconstruction Finance Corp. Department or Secretary of Homeland Security Unidentifiable International Entity