In the case of National Labor Relations Board v. Local 476, United Association of Journeymen of the Plumbing and Pipefitting Industry, AFL-CIO et al., in 1961, the Supreme Court ruled on a dispute involving union practices. The issue at hand was whether a union could require its members to work only for employers who had contracts with that specific union - an arrangement known as a "union shop" agreement. The National Labor Relations Board (NLRB) argued this practice violated federal labor laws prohibiting unfair labor practices by limiting employment opportunities based solely on membership or non-membership in any particular labor organization. In contrast, the Union contended these agreements were lawful under Section 8(e) of the National Labor Relations Act which allows unions and employers to agree upon maintaining certain standards such as wages and working conditions. The Supreme Court sided with NLRB stating that while Section 8(e) does allow for some restrictions regarding employer-employee relationships within collective bargaining agreements; it doesn't permit blanket prohibitions against employees working for non-contracting employers simply because they are not part of their specific union's contract network.

In the dissenting opinion for the case of NATIONAL LABOR RELATIONS BOARD v. LOCAL 476, UNITED ASSOCIATION OF JOURNEYMEN OF THE PLUMBING AND PIPEFITTING INDUSTRY, AFL-CIO, et al., Justice Frankfurter argued that the majority's decision was a departure from established principles governing labor disputes. He contended that it was not within the jurisdiction of National Labor Relations Board (NLRB) to decide whether an employer had violated its collective bargaining agreement with a union by subcontracting work without first negotiating with said union. The justice believed this issue should be resolved through arbitration as provided in most collective bargaining agreements and not through NLRB proceedings which are designed to prevent unfair labor practices rather than interpret contract terms. Furthermore, he expressed concern over potential conflicts between decisions made by arbitrators and those made by NLRB if both were allowed to rule on such matters.