In the 1944 case of Western Union Telegraph Co. v. Lenroot, Chief of Children's Bureau, United States Department of Labor, the Supreme Court ruled in favor of Western Union Telegraph Company. The company had been charged with violating child labor laws by employing a messenger who was under the age limit set by federal law for such jobs. However, it argued that its messengers were not engaged in commerce or production for commerce as defined by these laws and thus should be exempt from them. The court agreed with this argument and held that while Congress has broad power to regulate interstate commerce under the Commerce Clause of the Constitution, this power does not extend to regulation over working conditions or employment practices unless they have a direct effect on interstate commerce.

In the dissenting opinion for Western Union Telegraph Co. v. Lenroot, Chief of Children's Bureau, United States Department of Labor (1944), Justice Frank Murphy argued that the majority had misinterpreted the Fair Labor Standards Act by excluding messengers employed by telegraph companies from its protections. He contended that Congress intended to include all workers engaged in commerce or in the production of goods for commerce within this act’s scope unless explicitly excluded. The majority's narrow interpretation was inconsistent with both legislative intent and previous court decisions interpreting similar language in other statutes such as National Labor Relations Act and Social Security Act which included telegraph messengers under their purview. Furthermore, he pointed out that these young messengers were precisely the kind of vulnerable workers whom Congress sought to protect through labor legislation like FLSA.