In the 1957 case Local 1976, United Brotherhood of Carpenters and Joiners of America, A.F.L. v. National Labor Relations Board (NLRB), the Supreme Court ruled on a dispute involving union practices and labor laws. The Carpenter's Union had been excluding non-union workers from job sites by refusing to work with them, which was deemed as an unfair labor practice under Section 8(b)(1)(A) of the National Labor Relations Act (NLRA). The NLRB argued that this behavior violated federal law because it restrained or coerced employees in their rights guaranteed by Section 7 of NLRA - specifically, their right to refrain from collective bargaining or other mutual aid protection activities without fear of reprisal from unions. In a unanimous decision led by Justice Tom C. Clark, the Supreme Court upheld lower court rulings in favor of NLRB stating that such conduct indeed constituted restraint and coercion prohibited by NLRA.

In the dissenting opinion for the case of Local 1976, United Brotherhood of Carpenters and Joiners of America, A.F.L., et al. v. National Labor Relations Board (1957), Justice Frankfurter argued that the majority's decision was a departure from established principles governing labor relations. He contended that it failed to respect Congress' intent in passing the National Labor Relations Act by allowing an employer to be held liable for unfair labor practices committed by a union with which it had no direct relationship or control over its actions. Furthermore, he disagreed with how broadly "employer" was defined in this context and believed that such interpretation could potentially lead to unjust outcomes where employers are punished for acts they did not commit or have any influence over. He also expressed concern about potential implications on freedom of association rights under First Amendment protections if unions were considered agents of employers simply because they shared common objectives.