Under D's longstanding approach, an employer may rebut that presumption of employee support of a union by showing that, at the time of the refusal to bargain, either (1) the union did not enjoy majority support, or (2) the employer had a 'good-faith' doubt, founded on a sufficient objective basis, of the union's majority support. D has long presumed that new employees hired in nonstrike circumstances support the incumbent union in the same proportion as the employees they replace. D has been all over the place with respect to a presumption for employees hired during a strike. Initially, D appeared to assume that replacements did not support the union. A year later D 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. In 1987, D 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. D held that it would not apply any presumption regarding striker replacements' union sentiments, but would determine their views on a case-by-case basis. In 1970, the Board certified Teamsters Local 968, as the collective-bargaining agent for P's production and maintenance employees. On May 21, 1979, P made its final offer for a new agreement on May 25, but the Union rejected that offer. P then locked out the 27 bargaining unit employees. The Union then commenced an economic strike. Five employees immediately crossed the picket line and reported for work. P hired 29 permanent replacement employees to replace the 22 strikers. The Union ended its strike offering to accept unconditionally P's May 25 contract offer. P stated that the offer was no longer available. P 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. 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. The Union filed an unfair labor practice charge. The General Counsel found that P had violated §§ 8(a)(1) and 8(a)(5) of the NLRA. P claimed that it had a reasonably based, good-faith doubt of the Union's majority status. The Administrative Law Judge agreed with P and dismissed the complaint. The Board reversed, holding that respondent lacked sufficient objective basis to doubt the Union's majority support. The Board applied the no presumption policy for strike-replacement workers. D ordered P to bargain. P appealed, and the Court of Appeals refused to enforce the order. The Supreme Court granted certiorari.