For more than 20 years, a union represented maintenance workers at Fibreboard Paper Products Corp. (defendant). But when the union announced plans to renegotiate the expiring collective-bargaining agreement between them, the employer decided that contracting the maintenance work out was more affordable, terminated its maintenance workers, and brought in a third-party contractor. The union promptly picketed and filed charges with the National Labor Relations Board (NLRB) (plaintiff), alleging the company failed to negotiate with the union. The NLRB found that economic rather than anti-union motives prompted the company to contract out the work but that the company nonetheless failed to negotiate with the union as required by the National Labor Relations Act (NLRA). As a result, the NLRB ordered the company to reinstate the workers with backpay and to bargain with the union, and the appellate court affirmed the NLRB order. The Supreme Court granted review only as to the issue of whether contracting out work previously performed by employees in a bargaining unit falls within “terms and conditions of employment” subject to mandatory bargaining under the NLRA.