In the United States v. Petrillo case of 1946, the Supreme Court upheld a federal law that prohibited radio networks from firing employees in favor of recorded programming. The defendant, James Caesar Petrillo, head of the American Federation of Musicians (AFM), was charged with violating this law by encouraging a strike against Chicago radio stations to protest their use of recorded music. He argued that the law violated his First Amendment rights and interfered with labor relations under exclusive jurisdiction of National Labor Relations Board (NLRB). However, the court ruled 5-3 in favor of upholding it as constitutional since Congress had power to regulate interstate commerce which included broadcasting industry and could protect jobs threatened by technological advances such as phonograph records. This decision affirmed government's ability to intervene when technology threatens employment.

In the dissenting opinion for United States v. Petrillo, Justice Frank Murphy argued that the law in question, which criminalized certain types of labor strikes during World War II, was an unconstitutional violation of free speech rights. He contended that Congress had overstepped its bounds by attempting to regulate peaceful and legitimate union activities under the guise of wartime necessity. Furthermore, he believed that this law unfairly targeted unions while ignoring other potential sources of disruption to war production such as corporate greed or mismanagement. In his view, it was not within Congress's power to decide what constitutes a "reasonable" strike or picketing activity; these were matters best left up to negotiation between workers and employers themselves.