The case of Public Utilities Commission of California v. United States in 1957 revolved around the issue of whether a state regulatory commission could impose conditions on a federal agency's approval to abandon railway lines. The Interstate Commerce Commission (ICC) had granted permission to Southern Pacific Railroad Company to abandon certain rail lines, but the California Public Utilities Commission sought to impose additional conditions on this abandonment. The Supreme Court ruled that while states have some power over local aspects of interstate commerce, they cannot interfere with decisions made by federal agencies like the ICC under its congressionally delegated authority. Therefore, it was held that the state commission did not have jurisdiction or authority to add further stipulations onto an order issued by a federal body such as ICC and thus affirmed supremacy clause principles - where Federal law takes precedence over State law when there is conflict between them.

In the dissenting opinion for Public Utilities Commission of California v. United States, Justice Frankfurter disagreed with the majority's interpretation of federal law as preemptive over state regulations regarding railroad rates. He argued that Congress did not intend to prevent states from imposing their own standards when it passed legislation regulating interstate commerce in this area. Instead, he believed that federal laws were meant to provide a minimum standard and states should be allowed to impose stricter rules if they wished. Furthermore, he contended that there was no evidence showing these additional state requirements would interfere with national uniformity or impede interstate commerce - which are key reasons for preemption under the Supremacy Clause of the Constitution. Thus, according to him, allowing California’s regulation wouldn’t disrupt but rather complement existing federal oversight on railroads' freight rates.