In the case of American Federation of Labor et al. v. National Labor Relations Board, 1939, the U.S Supreme Court was asked to determine whether a labor union could be charged with unfair labor practices under Section 8(2) and (3) of the National Labor Relations Act for causing an employer to discriminate against employees who were not members of that union. The court ruled in favor of the National Labor Relations Board (NLRB), holding that unions can indeed be held accountable for such actions under these sections. This decision clarified that both employers and unions have responsibilities under this act to ensure fair treatment and non-discrimination in employment based on union membership status.

In the dissenting opinion for the case of American Federation of Labor et al. v. National Labor Relations Board, Justice James Clark McReynolds argued that Congress had overstepped its constitutional bounds by passing the Wagner Act (National Labor Relations Act). He believed that this act interfered with states' rights to manage their own labor relations and infringed upon employers' freedom of speech and association. Furthermore, he contended that it was not within Congress's power under the Commerce Clause to regulate labor disputes as they did not directly affect interstate commerce. He also criticized the majority's interpretation of "affecting commerce" as overly broad and warned against expanding federal authority in such a manner.