In Pflueger et al. v. Sherman et al., the U.S Supreme Court was tasked with deciding on a case involving an alleged violation of the Sherman Anti-Trust Act by several automobile manufacturers and distributors in Hawaii. The plaintiffs, who were independent car dealerships, claimed that these companies had conspired to fix prices and control distribution channels for automobiles and parts in Hawaii, thereby creating a monopoly which violated federal antitrust laws. However, the defendants argued that their actions did not constitute interstate commerce as required under the act because all transactions occurred within Hawaii itself. The court ruled in favor of the defendants stating that while they may have been involved in activities related to interstate commerce (such as shipping cars from mainland US), their actual business operations - buying/selling vehicles & parts - took place entirely within one state i.e., Hawaii; hence it didn't fall under purview of federal regulation via Sherman Act.

In the dissenting opinion for Pflueger et al. v. Sherman et al., Justice McReynolds disagreed with the majority's decision to uphold a lower court ruling that allowed an injunction against picketing by union workers at a non-union shop, arguing it violated their First Amendment rights of free speech and assembly. He contended that peaceful picketing was not inherently unlawful or harmful, but rather a legitimate means of communication between laborers and employers in industrial disputes. Furthermore, he argued that the case did not involve any violence or intimidation on part of the union members towards non-union employees or customers; hence there was no justification for such drastic legal intervention as an injunction against them. The justice also expressed concern about potential misuse of judicial power to suppress lawful expressions of protest by working people seeking better conditions through collective action.