In the case of Babbitt, Governor of Arizona, et al. v. United Farm Workers National Union et al., 1978, the Supreme Court ruled on a dispute regarding an Arizona law that regulated farm labor relations and restricted secondary boycotts by agricultural workers. The United Farm Workers union challenged this law as unconstitutional under both federal labor laws and First Amendment rights to free speech and assembly. However, the court upheld most provisions of the state's legislation in a 7-2 decision. The majority opinion held that states have authority to regulate agricultural labor relations when no specific federal regulations exist for such matters; thus it did not violate Supremacy Clause principles or infringe upon areas pre-empted by national policy. Furthermore, they found restrictions on secondary boycotts were permissible limitations on conduct rather than infringements upon protected speech or assembly rights. However, one provision was struck down: requiring unions to give notice before striking was deemed an impermissible burden on worker rights under equal protection grounds because similar requirements were not imposed upon employers contemplating lockouts.

In the dissenting opinion for Babbitt v. United Farm Workers National Union, Justice William Brennan disagreed with the majority's ruling that Arizona's limitation on consumer publicity was constitutional under the First Amendment. He argued that such a restriction is an infringement upon free speech and should be subjected to strict scrutiny review - a standard of judicial review used in cases where fundamental rights are allegedly violated. Brennan contended that this law did not serve any compelling state interest nor was it narrowly tailored to achieve its intended purpose without unnecessarily infringing upon First Amendment rights. Furthermore, he believed there were less restrictive means available for achieving the same goal, thereby making this law unconstitutional by his interpretation.