opinion: Justice Marshall
  delivered the opinion of the Court.
  This case presents the question whether the National Labor Relations Board (NLRB or Board), in evaluating an employer’s claim that it had a reasonable basis for doubting a union’s majority support, must presume that striker replacements oppose the union. We hold that the Board acted within its discretion in refusing to adopt a presumption of replacement opposition to the union and therefore reverse the judgment of the Court of Appeals.
  I
  Upon certification by the NLRB as the exclusive bargaining agent for a unit of employees, a union enjoys an irrebuttable presumption of majority support for one year. Fall River Dyeing & Finishing Corp. v. NLRB, 482 U. S. 27, 37 (1987). During that time, an employer’s refusal to bargain with the union is per se an unfair labor practice under §§ 8(a)(1) and 8(a)(5) of the National Labor Relations Act (NLRA), 49 Stat. 452, as amended, 29 U. S. C. §§ 158(a)(1), 158(a)(5). See Celanese Corp. of America, 95 N. L. R. B. 664, 672 (1951); R. Gorman, Labor Law, Unionization and Collective Bargaining 109 (1976). After the first year, the presumption continues but is rebuttable. Fall River, supra, at 38. Under the Board’s longstanding approach, an employer may rebut that presumption by showing that, at the time of the refusal to bargain, either (1) the union did not in fact enjoy majority support, or (2) the employer had a “good-faith” doubt, founded on a sufficient objective basis, of the union’s majority support. Station KKHI, 284 N. L. R. B. 1339 (1987), enf’d, 891 F. 2d. 230 (CA9 1989). The question presented in this case is whether the Board must, in determining whether an employer has presented sufficient objective evidence of a good-faith doubt, presume that striker replacements oppose the union.
  The Board has long presumed that new employees hired in nonstrike circumstances support the incumbent union in the same proportion as the employees they replace. See, e. g., National Plastic Products Co., 78 N. L. R. B. 699, 706 (1948). The Board’s approach to evaluating the union sentiments of employees hired to replace strikers, however, has not been so consistent. Initially, the Board appeared to assume that replacements did not support the union. See, e. g., Stoner Rubber Co., 123 N. L. R. B. 1440, 1444 (1959) (stating that it was not “unreasonable [for the employer] to assume that none of the . . . permanent replacements were union adherents”); Jackson Mfg. Co., 129 N. L. R. B. 460, 478 (1960) (stating that it was “most improbable” that replacements desired representation by the strikers’ union); Titan Metal Mfg. Co., 135 N. L. R. B. 196, 215 (1962) (finding that employer had “good cause to doubt the Union’s majority” because “no evidence that any of the replacements had authorized the Union to represent them” had been presented); S & M Mfg. Co., 172 N. L. R. B. 1008, 1009 (1968) (same).
  A1974 decision, Peoples Gas System, Inc., 214 N. L. R. B. 944 (1974), rev’d and remanded on other grounds sub nom. Teamsters Local Union 769 v. NLRB, 174 U. S. App. D. C. 310, 316, 532 F. 2d 1385, 1391 (1976), signalled a shift in the Board’s approach. The Board recognized that “it is of course possible that the replacements, who had chosen not to engage in the strike activity, might nevertheless have favored union representation.” 214 N. L. R. B., at 947. Still, the Board held that “it was not unreasonable for [the employer] to infer that the degree of union support among these employees who had chosen to ignore a Union-sponsored picket line might well be somewhat weaker than the support offered by those who had vigorously engaged in concerted activity on behalf on [sic] Union-sponsored objectives.” Ibid.
  A year later, in Cutten Supermarket, 220 N. L. R. B. 507 (1975), the Board reversed course completely, stating that striker replacements, like new employees generally, are presumed to support the union in the same ratio as the strikers they replaced. Id., at 509. The Board’s initial adherence to this new approach, however, was equivocal. In Arkay Packaging Corp., 227 N. L. R. B. 397 (1976), review denied sub nom. New York Printing Pressmen & Offset Workers Union, No. 51 v. NLRB, 575 F. 2d 1045 (CA2 1978), the Board stated that “it would be wholly unwarranted and unrealistic to presume as a matter of law that, when hired, the replacements for the union employees who had gone out on strike favored representation by the Unions to the same extent as the strikers.” 227 N. L. R. B., at 397-398. See also Beacon Upholstery Co., 226 N. L. R. B. 1360, 1368 (1976) (distinguishing Cutten Supermarket on the ground that the strikers in Beacon Upholstery had been lawfully discharged, so there were no striking employees in the bargaining unit). Nevertheless, in Windham Community Memorial Hospital, 230 N. L. R. B. 1070 (1977), enf’d, 577 F. 2d 805 (CA2 1978), the Board explicitly reaffirmed Cutten Supermarket, stating that “[t]he general rule ... is that new employees, including striker replacements, are presumed to support the union in the same ratio as those whom they have replaced.” 230 N. L. R. B., at 1070. The Board distinguished Arkay Packaging as a “limited exception” to this rule based on “the unique circumstance that the union had apparently abandoned the bargaining unit.” 230 N. L. R. B., at 1070. Finally, in 1980, the Board reiterated that the presumption that new employees support the union applies equally to striker replacements. Pennco, Inc., 250 N. L. R. B. 716, 717-718 (1980), enf’d, 684 F. 2d 340 (CA6), cert. denied, 459 U. S. 994 (1982).
  In 1987, after several Courts of Appeals rejected the Board’s approach, the Board determined that no universal generalizations could be made about replacements’ union sentiments that would justify a presumption either of support for or of opposition to the union. Station KKHI, 284 N. L. R. B. 1339 (1987). On the one hand, the Board found that the prounion presumption lacked empirical foundation because “incumbent unions and strikers sometimes have shown hostility toward the permanent replacements,” and “replacements are typically aware of the union’s primary concern for the striker’s welfare, rather than that of the replacements.” Id., at 1344. On the other hand, the Board found that an antiunion presumption was “equally unsupportable” factually. Ibid. The Board observed that a striker replacement “may be forced to work for financial reasons, or may disapprove of the strike in question but still desire union representation and would support other union initiatives.” Ibid. Moreover, the Board found as a matter of policy that adoption of an antiunion presumption would “substantially impair the employees’ right to strike by adding to the risk of replacement the risk of loss of the bargaining representative as soon as replacements equal in number to the strikers are willing to cross the picket line. ” Ibid. See also Pennco, Inc., 250 N. L. R. B., at 717. Accordingly, the Board held that it would not apply any presumption regarding striker replace-merits’ union sentiments, but would determine their views on a case-by-case basis. 284 N. L. R. B., at 1344-1345.
  II
  We now turn to the Board’s application of its Station KKHI no-presumption approach in this case. Respondent Curtin Matheson Scientific, Inc., buys and sells laboratory instruments and supplies. In 1970, the Board certified Teamsters Local 968, General Drivers, Warehousemen and Helpers (hereinafter Union) as the collective-bargaining agent for respondent’s production and maintenance employees. On May 21, 1979, the most recent bargaining agreement between respondent and the Union expired. Respondent made its final offer for a new agreement on May 25, but the Union rejected that offer. Respondent then locked out the 27 bargaining-unit employees. On June 12, respondent renewed its May 25 offer, but the Union again rejected it. The Union then commenced an economic strike. The record contains no evidence of any strike-related violence or threats of violence.
  Five employees immediately crossed the picket line and reported for work. On June 25, while the strike was still in effect, respondent hired 29 permanent replacement employees to replace the 22 strikers. The Union ended its strike on July 16, offering to accept unconditionally respondent’s May 25 contract offer. On July 20, respondent informed the Union that the May 25 offer was no longer available. In addition, respondent withdrew recognition from the Union and refused to bargain further, stating that it doubted that the Union was supported by a majority of the employees in the unit. Respondent subsequently refused to provide the Union with information it had requested concerning the total number of bargaining-unit employees on the payroll, and the job classification and seniority of each employee. As of July 20, the bargaining unit consisted of 19 strikers, 25 permanent replacements, and the 5 employees who had crossed the picket line at the strike’s inception.
  On July 30, the Union filed an unfair labor practice charge with the Board. Following an investigation, the General Counsel issued a complaint, alleging that respondent’s withdrawal of recognition, refusal to execute a contract embodying the terms of the May 25 offer, and failure to provide the requested information violated §§ 8(a)(1) and 8(a)(5) of the NLRA, 29 U. S. C. §§ 158(a)(1), 158(a)(5). In its defense to the charge, respondent claimed that it had a reasonably based, good-faith doubt of the Union’s majority status. The Administrative Law Judge agreed with respondent and dismissed the complaint. The Board, however, reversed, holding that respondent lacked sufficient objective basis to doubt the Union’s majority support. 287 N. L. R. B. 350 (1987).
  First, the Board noted that the crossover of 5 of the original 27 employees did not in itself support an inference that the 5 had repudiated the Union, because their failure to join the strike may have “indicate® their economic concerns rather than a lack of support for the union.” 287 N. L. R. B., at 352. Second, the Board found that the resignation from their jobs of two of the original bargaining-unit employees, including the chief shop steward, after the commencement of the strike did not indicate opposition to the Union, but merely served to reduce the size of the bargaining unit as of the date of respondent’s withdrawal of recognition. Ibid. Third, the Board discounted statements made by six employees to a representative of respondent during the strike. Although some of these statements may have indicated rejection of the Union as the bargaining representative, the Board noted, others “appealed] ambiguous at best.” Id., at 353. Moreover, the Board stated, “[e]ven attributing to them the meaning most favorable to the Respondent, it would merely signify that 6 employees of a total bargaining unit of approximately 50 did not desire to keep the Union as the collective-bargaining representative.” Ibid
  Finally, regarding respondent’s hiring of striker replacements, the Board stated that, in acccordance with the Station KKHI approach, it would “not use any presumptions with respect to [the replacements’] union sentiments,” but would instead “take a case-by-case approach [and] require additional evidence of a lack of union support on the replacements’ part in evaluating the significance of this factor in the employer’s showing of good-faith doubt.” 287 N. L. R. B., at 352. The Board noted that respondent’s only evidence of the replacements’ attitudes toward the Union was its employee relations director’s account of a conversation with one of the replacements. The replacement employee reportedly told her that he had worked in union and nonunion workplaces and did not see any need for a union as long as the company treated him well; in addition, he said that he did not think the Union in this case represented the employees. Id., at 351; see n. 4, supra. The Board did not determine whether this statement indicated the replacement employee’s repudiation of the Union, but found that the statement was, in any event, an insufficient basis for “inferring the union sentiments of the replacement employees as a group.” 287 N. L. R. B., at 353.
  The Board therefore concluded that “the evidence [was] insufficient to rebut the presumption of the Union’s continuing majority status.” Ibid. Accordingly, the Board held that respondent had violated §§ 8(a)(1) and 8(a)(5) by withdrawing recognition from the Union, failing to furnish the requested information, and refusing to execute a contract embodying the terms respondent had offered on May 25, 1979. The Board ordered respondent to bargain with the Union on request, provide the requisite information, execute an agreement, and make the bargaining-unit employees whole for whatever losses they had suffered from respondent’s failure to execute a contract.
  The Court of Appeals, in a divided opinion, refused to enforce the Board’s order, holding that respondent was justified in doubting the Union’s majority support. 859 F. 2d 362 (CA5 1988). Specifically, the court rejected the Board’s decision not to apply any presumption in evaluating striker replacements’ union sentiments and endorsed the so-called “Gorman presumption” that striker replacements oppose the union. We granted certiorari, 492 U. S. 905 (1989), to resolve a Circuit split on the question whether the Board must presume that striker replacements oppose the union.
  Ill
  A
  This Court has emphasized often that the NLRB has the primary responsibility for developing and applying national labor policy. See, e. g., Beth Israel Hospital v. NLRB, 437 U. S. 483, 500-501 (1978); NLRB v. Erie Resistor Corp., 373 U. S. 221, 236 (1963); NLRB v. Truck Drivers, 353 U. S. 87, 96 (1957).
  “Because it is to the Board that Congress entrusted the task 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,’ that body, if it is to accomplish the task which Congress set for it, necessarily must have authority to formulate rules to fill the interstices of the broad statutory provisions.” Beth Israel Hospital, supra, at 500-501 (quoting Republic Aviation Corp. v. NLRB, 324 U. S. 793, 798 (1945)).
  This Court therefore has accorded Board rules considerable deference. See Fall River Dyeing & Finishing Corp. v. NLRB, 482 U. S., at 42; NLRB v. Iron Workers, 434 U. S. 335, 350 (1978). We will uphold a Board rule as long as it is rational and consistent with the Act, Fall River, supra, at 42, even if we would have formulated a different rule had we sat on the Board, Charles D. Bonanno Linen Service, Inc. v. NLRB, 454 U. S. 404, 413, 418 (1982). Furthermore, a Board rule is entitled to deference even if it represents a departure from the Board’s prior policy. See NLRB v. J. Weingarten, Inc., 420 U. S. 251, 265-266 (1975) (“The use by an administrative agency of the evolutional approach is particularly fitting. To hold that the Board’s earlier decisions froze the development of this important aspect of the national labor law would misconceive the nature of administrative decisionmaking”). Accord, Iron Workers, supra, at 351.
  B
  Before assessing the Board’s justification for rejecting the antiunion presumption, we will make clear precisely how that presumption would differ in operation from the Board’s current approach. As noted above, see supra, at 777-778, the starting point for the Board’s analysis is the basic presumption that the union is supported by a majority of bargaining-unit employees. The employer bears the burden of rebutting that presumption, after the certification year, either by showing that the union in fact lacks majority support or by demonstrating a sufficient objective basis for doubting the union’s majority status. Respondent here urges that in evaluating an employer’s claim of a good-faith doubt, the Board must adopt a second, subsidiary presumption — that replacement employees oppose the union. Under this approach, if a majority of employees in the bargaining unit were striker replacements, the employer would not need to offer any objective evidence of the employees’ union sentiments to rebut the presumption of the union’s continuing majority status. The presumption of the replacements’ opposition to the union would, in effect, override the presumption of continuing majority status. In contrast, under its no-presumption approach, the Board “take[s] into account the particular circumstances surrounding each strike and the hiring of replacements, while retaining the long-standing requirement that the employer must come forth with some objective evidence to substantiate his doubt of continuing maj ority status. ” 859 F. 2d, at 370 (Williams, J., dissenting).
  C
  We find the Board’s no-presumption' approach rational as an empirical matter. Presumptions normally arise when proof of one fact renders the existence of another fact “so probable that it is sensible and timesaving to assume the truth of [the inferred] fact. . . until the adversary disproves it.” E. Cleary, McCormick on Evidence §343, p. 969 (3d ed. 1984). Although replacements often may not favor the incumbent union, the Board reasonably concluded, in light of its long experience in addressing these issues, that replacements may in some circumstances desire union representation despite their willingness to cross the picket line. Economic concerns, for instance, may force a replacement employee to work for a struck employer even though he otherwise supports the union and wants the benefits of union representation. In this sense the replacement worker is no different from a striker who, feeling the financial heat of the strike on himself and his family, is forced to abandon the picket line and go back to work. Cf. Lyng v. Automobile Workers, 485 U. S. 360, 371 (1988) (recognizing that “a striking individual faces an immediate and often total drop in income during a strike”). In addition, a replacement, like a nonstriker or a strike crossover, may disagree with the purpose or strategy of the particular strike and refuse to support that strike, while still wanting that union’s representation at the bargaining table.
  Respondent insists that the interests of strikers and replacements are diametrically opposed and that unions inevitably side with the strikers. For instance, respondent argues, picket-line violence often stems directly from the hiring of replacements. Furthermore, unions often negotiate with employers for strike settlements that would return the strikers to their jobs, thereby displacing some or all of the replacements. See Belknap, Inc. v. Hale, 463 U. S. 491, 513-514 (1983) (Blackmun, J., concurring in judgment). Respondent asserts that replacements, aware of the union’s loyalty to the strikers, most likely would not support the union. See, e. g., Leveld Wholesale, Inc., 218 N. L. R. B. 1344, 1350 (1975) (“Strike replacements can reasonably foresee that, if the union is successful, the strikers will return to work and the strike replacements will be out of a job”). In a related argument, respondent contends that the Board’s no-presumption approach is irreconcilable with the Board’s decisions holding that employers have no duty to bargain with a striking union over replacements’ employment terms because the “inherent conflict” between strikers and replacements renders the union incapable of “bargaining] simultaneously in the best interests of both strikers and their replacements.” Service Electric Co., 281 N. L. R. B. 633, 641 (1986); see also Leveld Wholesale, supra, at 1350.
  These arguments do not persuade us that the Board’s position is irrational. Unions do not inevitably demand displacement of all strike replacements. In Dold Foods, Inc., 289 N. L. R. B. 1323 (1988), the Board based its refusal to presume that the replacements opposed the union in part on this ground:
  “[U]nions often demand, at least in the first instance, that the replacements be discharged and the strikers rehired. Frequently, as in the instant case, the union’s position may be modified in the course of the negotiations on the issues underlying the strike. Indeed, in the instant case, as the strike wore on, the Union took a progressively weaker position until... it requested only that the Respondent discharge those replacements (about 32 out of 201 total replacements) who had not yet completed the probationary period.” Ibid, (citation omitted).
  The extent to which a union demands displacement of permanent replacement workers logically will depend on the union’s bargaining power. Under this Court’s decision in NLRB v. Mackay Radio & Telegraph Co., 304 U. S. 333 (1938), an employer is not required to discharge permanent replacements at the conclusion of an economic strike to make room for returning strikers; rather, the employer must only reinstate strikers as vacancies arise. The strikers’ only chance for immediate reinstatement, then, lies in the union’s ability to force the employer to discharge the replacements as a condition for the union’s ending the strike. Unions’ leverage to compel such a strike settlement will vary greatly from strike to strike. If, for example, the jobs at issue do not require highly trained workers and the replacements perform as well as the strikers did, the employer will have little incentive to hire back the strikers and fire the replacements; consequently, the union will have little bargaining power. Consumers’ reaction to a strike will also determine the union’s bargaining position. If the employer’s customers have no reluctance to cross the picket line and deal with the employer, the union will be in a poor position to bargain for a favorable settlement. Thus, a union’s demands will inevitably turn on the strength of the union’s hand in negotiations. A union with little bargaining leverage is unlikely to press the employer — at least not very forcefully or for very long — to discharge the replacements and reinstate all the strikers. Cognizant of the union’s weak position, many if not all of the replacements justifiably may not fear that they will lose their jobs at the end of the strike. They may still want that union’s representation after the strike, though, despite the union’s lack of bargaining strength during the strike, because of the union’s role in processing grievances, monitoring the employer’s actions, and performing other nonstrike roles. Because the circumstances of each strike and the leverage of each union will vary greatly, it was not irrational for the Board to reject the antiunion presumption and adopt a case-by-case approach in determining replacements’ union sentiments.
  Moreover, even if the interests of strikers and replacements conflict during the strike, those interests may converge after the strike, once job rights have been resolved. Thus, while the strike continues, a replacement worker whose job appears relatively secure might well want the union to continue to represent the unit regardless of the union’s bargaining posture during the strike. Surely replacement workers are capable of looking past the strike in considering whether or not they desire representation by the union. For these reasons, the Board’s refusal to adopt an antiunion presumption is not irreconcilable with its position in Service Electric, supra, and Leveld Wholesale, 218 N. L. R. B. 1344 (1975), regarding an employer’s obligation to bargain with a striking union over replacements’ employment terms.
  Furthermore, the Board has not deemed picket-line violence or a union’s demand that replacements be terminated irrelevant to its evaluation of replacements’ attitudes toward the union. The Board’s position, rather, is that “the hiring of permanent replacements who cross a picket line, in itself, does not support an inference that the replacements repudiate the union as collective-bargaining representative.” Station KKHI, 284 N. L. R. B., at 1344 (emphasis added). In both Station KKHI and this case, the Board noted that the picket line was peaceful, id., at 1345; 287 N. L. R. B., at 352; and in neither case did the employer present evidence that the union was actively negotiating for ouster of the replacements. To the extent that the Board regards evidence of these factors relevant to its evaluation of replacements’ union sentiments, then, respondent’s contentions ring hollow. Cf. Stormor, Inc., 268 N. L. R. B. 860, 866-867 (1984) (concluding that replacements’ crossing of picket line in face of continued violence, together with other evidence, overcame Board’s former presumption that replacements favored the union); IT Services, 263 N. L. R. B. 1183, 1185-1188 (1982) (holding that picket line violence and union’s adamant demand that replacements be terminated, together with anti-union statements by most of replacements, overcame pro-union presumption).
  In sum, the Board recognized that the circumstances surrounding each strike and replacements’ reasons for crossing a picket line vary greatly. Even if replacements often do not support the union, then, it was not irrational for the Board to conclude that the probability of replacement opposition to the union is insufficient to justify an antiunion presumption.
  D
  The Board’s refusal to adopt an antiunion presumption is also consistent with the Act’s “overriding policy” of achieving “‘industrial peace.’” Fall River, 482 U. S., at 38 (quoting Brooks v. NLRB, 348 U. S. 96, 103 (1954)). In Fall River, the Court held that the presumption of continuing majority support for a union “further[s] this policy by ‘promoting] stability in collective-bargaining relationships, without impairing the free choice of employees.’” 482 U. S., at 38 (citation omitted). The Court reasoned that this presumption “enable[s] a union to concentrate on obtaining and fairly administering a collective-bargaining agreement without worrying that, unless it produces immediate results, it will lose majority support.” Ibid, (citing Brooks v. NLRB, supra, at 100). In addition, this presumption “remove[s] any temptation on the part of the employer to avoid good-faith bargaining in the hope that, by delaying, it will undermine the union’s support among the employees.” 482 U. S., at 38.
  The Board’s approach to determining the union views of strike replacements is directed at this same goal because it limits employers’ ability to oust a union without adducing any evidence of the employees’ union sentiments and encourages negotiated solutions to strikes. It was reasonable for the Board to conclude that the antiunion presumption, in contrast, could allow an employer to eliminate the union merely by hiring a sufficient number of replacement employees. That rule thus might encourage the employer to avoid good-faith bargaining over a strike settlement, and instead to use the strike as a means of removing the union altogether. Cf. id., at 40 (“Without the presumptions of majority support ... , an employer could use a successor enterprise as a way of getting rid of a labor contract and of . . . eliminating the union’s] continuing presence”). Restricting an employer’s ability to use a strike as a means of terminating the bargaining relationship serves the policies of promoting industrial stability and negotiated settlements. Cf. NLRB v. Erie Resistor Corp., 373 U. S. 221, 233-234 (1963) (“[The Act’s] repeated solicitude for the 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”).
  Furthermore, it was reasonable for the Board to decide that the antiunion presumption might chill employees’ exercise of their statutory right to engage in “concerted activities,” including the right to strike. See 49 Stat. 452, as amended, 29 U. S. C. § 157 (“Employees shall have the right ... to engage in . . . concerted activities for the purpose of collective bargaining or other mutual aid or protection”). If an employer could remove a union merely by hiring a sufficient number of replacements, employees considering a strike would face not only the prospect of being permanently replaced, but also a greater risk that they would lose their bargaining representative, thereby diminishing their chance of obtaining reinstatement through a strike settlement. It was rational for the Board to conclude, then, that adoption of the antiunion presumption could chill employees’ exercise of their right to strike.
  Although the Board generally may not act “as an arbiter of the sort of economic weapons the parties can use,” NLRB v. Insurance Agents, 361 U. S. 477, 497 (1960), it may adopt rules restricting conduct that threatens to destroy the collective-bargaining relationship or that may impair employees’ right to engage in concerted activity. See, e. g., Charles D. Bonanno Linen Service v. NLRB, 454 U. S., at 412, 418-419 (upholding Board rule prohibiting employer’s unilateral withdrawal from multiemployer bargaining unit during impasse, “although it may deny an employer a particular economic weapon,” because rule advanced “pre-eminent goal” of stability in bargaining process); NLRB v. Erie Resistor Corp., supra, at 230-237 (upholding Board decision prohibiting employers from granting superseniority to strike replacements and strike crossovers because of damage superseniority would do to concerted activity and to future bargaining relationship); NLRB v. Great Dane Trailers, Inc., 388 U. S. 26, 34-35 (1967) (upholding Board decision that employer’s payment of vacation benefits to replacements, crossovers, and nonstrikers but not to strikers violated Act because of its destructive effect on concerted activity). The Board’s no-presumption approach is rationally directed at protecting the bargaining process and preserving employees’ right to engage in concerted activity. We therefore find, in light of the considerable deference we accord Board rules, see supra, at 786-787, that the Board’s approach is consistent with the Act.
  IV
  We hold that the Board’s refusal to adopt a presumption that striker replacements oppose the Union is rational and consistent with the Act. We therefore reverse the judgment of the Court of Appeals and remand for further proceedings consistent with this opinion.
  It is so ordered.
  Section 8 of the National Labor Relations Act 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 157 of this title;
  “(5) to refuse to bargain collectively with the representatives of his employees, subject to the provisions of section 159(a) of this title.” 29 U. S. C. §§ 158(a)(1), 158(a)(5).
  Justice Scalia’s assertion, post, at 801, 807 (dissenting opinion), that the question presented is whether “substantial evidence” supported the Board’s “factual finding” that a good-faith doubt was not established in this case misconstrues the issue. The question on which we granted the Board’s petition for certiorari is whether, in assessing whether a particular employer possessed a good-faith doubt, the Board must adopt a general presumption of replacement opposition to the union. See Pet. for Cert. I (“Whether, in assessing the reasonableness of an employer’s asserted doubt that an incumbent union enjoys continued majority support, the Board may refuse to apply any presumption regarding the extent of union support among replacements for striking employees”). Accord, Brief for Petitioner I. Whether the Board permissibly refused to adopt a general presumption applicable to all cases of this type is not an evidentiary question concerning the facts of this particular ease. The substantial evidence standard is therefore inapplicable to the issue before us. Rather, we must determine whether the Board’s refusal to adopt the presumption is rational and consistent with the Act. NLRB v. Baptist Hospital, Inc., 442 U. S. 773, 787 (1979) (“[T]he courts have the duty to review the Board’s presumptions both ‘for consistency with the Act, and for rationality’ ”) (quoting Beth Israel Hospital v. NLRB, 437 U. S. 483, 501 (1978)). Whether substantial evidence supports the Board’s finding that respondent did not possess an objectively reasonable doubt is a question for the Court of Appeals to consider, without applying any presumption about replacements’ views, on remand.
  See n. 7, infra.
  The Board also found that statements made by chief shop steward Shady Goodson before his resignation did not indicate his lack of support for the Union. Goodson reportedly told respondent’s employee relations director that he was in the middle of an uncomfortable situation in that the employees did not want the strike, that he was having difficulty staffing the picket line, and that the Union was not providing sufficient assistance in maintaining the picket line. The Board found that these statements “conveyed only a disapproval of the Union’s conduct of the strike,” and could not be “reasonably interpreted as a repudiation of the Union as the employees’ representative.” 287 N. L. R. B., at 352.
  According to respondent’s director of employee relations, Elizabeth Price, two of the crossover employees, Tony Lopez and Bill Lee, told her that the Union had done nothing for the employees and that they would not pay their union dues because they would not support the Union. Price also stated that striker J. R. Blackshire expressed his anger over the Union’s handling of strike payments and requested reinstatement. Black-shire also reportedly said that “there was no union[,] that people were not supporting it[, and] that there were other striking employees who wanted to return to work.” 287N. L. R. B.,at351. Price also stated that striker Clint Waller told her that he was not walking the picket line because he felt that the Union was not representing the employees, and that he wanted the strike to end. Waller later resigned from the Union. Striker Raymond Brunner reportedly told Price that he had thought about retiring because he no longer wanted to work with the Union. Price stated that striker replacement David Schneider told her that he did not think that the Union supported the employees and did not see any need for a union as long as the employer treated him well. Ibid.
  The “Gorman presumption” derives its name from Professor Robert Gorman’s statement in his labor law treatise that “if a new hire agrees to serve as a replacement for a striker (in union parlance, as a strikebreaker, or worse), it is generally assumed that he does not support the union and that he ought not be counted toward a union majority.” R. Gorman, Labor Law, Unionization and Collective Bargaining 112 (1976). In context, however, this statement does not appear to endorse a presumption, but seems merely to describe the Board’s former approach to evaluating replacements’ union sentiments. Id., at 112-113 (citing Titan Metal Mfg. Co., 135 N. L. R. B. 196 (1962)).
  In addition to the Fifth Circuit in this case, the First and Eighth Circuits have endorsed the presumption that striker replacements oppose the union, albeit in cases in which the Board had applied the contrary presumption rather than its present no-presumption approach. Soule Glass & Glazing Co. v. NLRB, 652 F. 2d 1055, 1110 (CA1 1981); National Car Rental System, Inc. v. NLRB, 594 F. 2d 1203, 1206 (CA8 1979). The Second and Sixth Circuits, however, have rejected the antiunion presumption in cases in which the Board had applied its prounion presumption. NLRB v. Windham Community Hospital, 577 F. 2d 805, 813 (CA2 1978); NLRB v. Pennco, Inc., 684 F. 2d 340 (CA6), cert. denied, 459 U. S. 994 (1982). The Ninth Circuit has not expressly rejected the antiunion presumption but has approved the Board’s no-presumption approach. See NLRB v. Buckley Broadcasting Corp., 891 F. 2d 230, 233-234 (1989).
  Contrary to respondent’s assertion, the Board’s no-presumption approach does not constitute an unexplained abandonment of the good-faith doubt defense to a refusal to bargain charge. The Board’s requirement of some objective evidence indicating replacements’ opposition to the union does not amount to a requirement that the employer prove that the union in fact lacks majority status. To show a good-faith doubt, an employer may rely on circumstantial evidence; to show an actual lack of majority support, however, the employer must make a numerical showing that a majority of employees in fact oppose the union. See, e. g., Stormor, Inc., 268 N. L. R. B. 860, 866-867 (1984) (noting that employer need not show actual loss of majority support to prove good-faith doubt). There is no basis for assuming, then, that the Board has, sub silentio, forsaken the good-faith doubt standard.
  The American Federation of Labor and Congress of Industrial Organizations, as amicus curiae, urges us to reject the good-faith doubt standard and hold that an employer, before withdrawing recognition of the union, must show actual loss of majority status through a Board-conducted election. See also Flynn, íhe Economic Strike Bar: Looking Beyond the “Union Sentiments” of Permanent Replacements, 61 Temple L. Rev. 691, 720 (1988). This Court has never expressly considered the validity of the good-faith doubt standard. Cf. Fall River Dyeing & Finishing Corp. v. NLRB, 482 U. S. 27, 41, n. 8 (1987) (citing Board’s good-faith doubt standard without passing ofi its validity). We decline to address that issue here, as both parties assume the validity of the standard, and resolution of the issue is not necessary to our decision. See United Parcel Service, Inc. v. Mitchell, 451 U. S. 56, 60, n. 2 (1981).
  Justice Scalia characterizes this view as “embarrassingly wide of the mark” and asserts, without any factual support, that unions “almost certainly]” demand displacement of striker replacements. Post, at 808 (dissenting opinion). We are confident that the Board, with its vast reservoir of experience in resolving labor disputes, is better situated than members of this Court to determine the frequency with which unions demand displacement of striker replacements.
  Furthermore, the facts of this ease belie Justice Scalia’s sweeping characterization of the inevitability of such demands, as the Union did not negotiate for the discharge of replacements as a condition for settling the strike. See infra, at 793. Contrary to Justice Scalia’s assertion, post, at 809, an unconditional offer to return to work is hardly the same thing as a demand that the employer discharge all the replacements and rehire the strikers as a condition for ending the strike. Here, at the time of respondent’s withdrawal of recognition from the Union, there were only 19 strikers and 25 replacements. Thus, it is unlikely that all the replacements would have lost their jobs even if all the strikers were reinstated. Depending on their particular jobs and skills, some replacements might not have felt threatened by the Union’s offer to have the strikers return to work. More importantly, a union’s offer turns into a demand only if the union can back up its position with a credible show of economic force. As explained above, supra, at 790-791, a union with little bargaining power is unlikely to be able to pressure the employer to reinstate the strikers. Absent record evidence to the contrary, then, we have no basis for questioning the Board’s factual finding that the Union was not pressing for discharge of the replacements in this case.
  Justice Scalia appears to misunderstand our position. See post, at 810-811 (dissenting opinion). We do not mean that the replacements’ attitudes toward the union after the strike are relevant to the Board’s determination. Rather, we mean only that during the strike a replacement may foresee that his interests favor representation by the union after the strike. Thus, even if he opposes the strike itself, he may nevertheless want the union to continue to represent the unit because of the benefits that will accrue to him from representation after the strike.
  Thus, assuming for the sake of argument that Justice Scalia’s supposition, post, at 808 (dissenting opinion), that unions “almost certain[ly]” demand displacement of all strike replacements is true, such demands will be a factor in the Board’s analysis in most cases. There is no reason, however, to force the Board to apply a presumption based on the premise that unions always make such demands when cases such as the one before us demonstrate that this premise is false.
  We do not mean to imply that adoption of the antiunion presumption would be inconsistent with the Act’s policy. That question is not before us.
  Justice Scalia entirely ignores the Board’s policy considerations, apparently on the rationale that policy is an illegitimate factor in the Board’s decision. See post, at 812-813 (dissenting opinion). This argument is founded on the premise that the issue before us is the factual question whether substantial evidence supports the Board’s finding that respondent lacked a good-faith doubt. As stated earlier, however, see supra at 778-779, n. 2, the real question is whether the Board must, in assessing the objective reasonableness of an employer’s doubt, adopt a particular presumption. Certainly the Board is entitled to consider both whether the presumption is factually justified and whether that presumption would dis-serve the Act’s policies. See Baptist Hospital, 442 U. S., at 787. We need not determine whether the Board’s policy considerations alone would justify its refusal to adopt the presumption urged by respondent because we find the Board's decision not irrational as a factual matter. See supra, at 788-793.