In the 1952 case of King et al. v. United States, the Florida Railroad and Public Utilities Commission (represented by King) challenged a decision made by the Interstate Commerce Commission (ICC). The ICC had approved an application from Seaboard Air Line Railway to discontinue two passenger trains operating in Florida due to financial losses. The state commission argued that this would leave certain areas without adequate service and claimed that federal law required railroads to provide such services even at a loss if necessary for public convenience. The Supreme Court ruled in favor of the ICC, stating it was within its authority under federal law to allow discontinuation of unprofitable train routes when deemed appropriate after considering all relevant factors including local needs. This ruling reinforced that states cannot impose their own regulatory requirements on interstate commerce where those requirements conflict with or impede decisions made under valid federal laws or regulations.

In the dissenting opinion for King et al., constituting the Florida Railroad and Public Utilities Commission, v. United States et al., 1952, Justice Frankfurter argued that the majority's decision to allow federal courts to enjoin state officials from enforcing state laws was a departure from established principles of federalism. He contended that this ruling undermined states' rights by allowing federal intervention in matters traditionally within their jurisdiction. Furthermore, he expressed concern about potential misuse of such injunctions and warned against expanding their use without careful consideration. He believed that it would be more appropriate for disputes between states and federally regulated industries to be resolved through negotiation or legislation rather than judicial intervention.