The U.S. Supreme Court case Illinois Commerce Commission et al. v. Thomson, Trustee (1942) revolved around the issue of whether a state could regulate intrastate rates for railroads that were part of an interstate network without violating the Interstate Commerce Act and the Constitution's commerce clause. The court ruled in favor of Thomson, stating that states have authority to regulate intrastate railroad rates even if they are part of an interstate system as long as it does not interfere with federal regulation or burden interstate commerce excessively. This decision affirmed the principle that while Congress has exclusive jurisdiction over matters related to interstate commerce, states retain their power to govern local aspects unless there is direct conflict between state and federal law.

In the dissenting opinion for Illinois Commerce Commission et al. v. Thomson, Trustee, Justice Frank Murphy argued that the majority's decision was a departure from established principles of federalism and state sovereignty. He contended that states should have primary authority over local matters such as intrastate railroad rates unless there is clear evidence of congressional intent to preempt state law. In this case, he did not believe such evidence existed and thus disagreed with the majority's interpretation of the Interstate Commerce Act as barring states from setting their own intrastate railroad rates when those rates might affect interstate commerce indirectly or incidentally. Furthermore, he expressed concern about potential negative consequences on local economies if states were unable to regulate these matters independently.