The collective-bargaining agreement (CBA) between Local 90, International Union of Electrical Workers and Gulton Electro-Voice, Inc. (collectively, defendants) gave union officers superseniority as to layoff and recall. In 1975, Gulton employees suggested limiting it to fewer officers, but the recording and financial secretaries still had superseniority although neither’s presence was necessary to resolving grievances. In 1980, granting the recording secretary superseniority meant Gulton laid off other employees. General counsel for the National Labor Relations Board (NLRB) brought charges against both the union and employer, alleging the superseniority provision unlawfully discriminated against employees based on union involvement. The administrative-law judge upheld the provision, but the NLRB unanimously reversed, applying a new presumption of legality only for superseniority provisions limited to layoff and recall of union officials whose on-the-job presence is necessary to administer the CBA. The union appealed, and the NLRB cross-petitioned for enforcement.