In the 1955 case of Local Union No. 25 of the International Brotherhood of Teamsters, Chauffeurs, Warehousemen and Helpers of America et al. v. New York, New Haven & Hartford Railroad Co., the Supreme Court ruled on a dispute between a union and a railroad company over picketing activities by the union at sites where goods were being loaded onto trucks for delivery to customers who had received them via rail shipment from out-of-state sources. The court held that such picketing was not protected under federal labor laws because it interfered with interstate commerce in violation of the Sherman Antitrust Act. This decision clarified that while unions have certain rights to engage in collective bargaining and other activities aimed at improving working conditions for their members, these rights do not extend to actions that disrupt or interfere with interstate commerce.

In the dissenting opinion for this case, Justice Frankfurter argued that the majority's decision was an overreach of federal power and a violation of states' rights. He contended that Congress did not intend to preempt state law when it passed the Railway Labor Act, as evidenced by its silence on the matter in legislative history. Furthermore, he pointed out that there is no conflict between federal and state law because both aim to prevent labor disputes from disrupting commerce. Therefore, he believed that New York should be allowed to enforce its own laws regarding union picketing without interference from federal courts or agencies. Finally, he warned against judicial activism and urged his colleagues to respect traditional boundaries between different branches of government.