In the case of Osman et al. v. Douds, Regional Director of the National Labor Relations Board in 1949, a group of employers challenged an order by the National Labor Relations Board (NLRB) that required them to cease and desist from certain unfair labor practices and to reinstate employees who had been discharged for union activities with back pay. The Supreme Court upheld this decision on appeal, ruling that substantial evidence supported the NLRB's findings that these employers had engaged in anti-union conduct which violated sections 8(1), 8(3), and 2(6) and (7) of the National Labor Relations Act. This included coercing employees not to join or assist labor organizations; discouraging membership in a labor organization through discrimination regarding hire or tenure; interfering with, restraining or coercing employees exercising their rights under section 7; dominating or interfering with any labor organization’s formation/administration/contribution support; contributing financial/other support to it; encouraging/discouraging membership therein by discrimination concerning terms/conditions of employment.

In the dissenting opinion for Osman et al. v. Douds, Justice Hugo Black argued that the majority's decision to uphold a provision of the Taft-Hartley Act requiring union leaders to swear they were not members of the Communist Party was unconstitutional. He believed it violated both freedom of speech and association protected under First Amendment rights as well as Fifth Amendment protections against self-incrimination. Furthermore, he contended that Congress had overstepped its bounds by legislating in an area reserved for states - labor relations within their borders - thereby violating principles of federalism enshrined in Tenth Amendment. Additionally, he criticized the law’s vagueness which could lead to arbitrary enforcement and potential misuse by those in power against political opponents or unpopular groups.