In the case of Republic Aviation Corp. v. National Labor Relations Board (1944), the U.S Supreme Court upheld a ruling by the National Labor Relations Board that employers could not prohibit employees from wearing union buttons or insignia at work, as it was considered an infringement on their rights to self-organization and collective bargaining under Section 7 of the National Labor Relations Act. The court also ruled that employers cannot prevent off-duty employees from remaining near company property for union-related activities unless there is a valid reason such as disturbance to production or discipline. This decision established important precedents regarding workers' rights in relation to unions and set guidelines for permissible employer conduct towards employee involvement in labor organizations.

In the dissenting opinion for Republic Aviation Corp. v. National Labor Relations Board, Justice Owen Roberts disagreed with the majority's decision to uphold the NLRB's ruling that employers cannot prohibit employees from wearing union insignia at work and soliciting membership during non-working hours on company property. He argued that these activities could disrupt workplace harmony and productivity, infringing upon an employer’s right to maintain order in their business operations. Furthermore, he contended that it was not within the NLRB’s jurisdiction to make such a broad policy determination without specific legislative guidance or statutory authority from Congress. In his view, this overstepped its bounds as an administrative agency by making law rather than interpreting it.