In the 1946 case Fleming, Temporary Controls Administrator v. Rhodes, Sheriff et al., the U.S Supreme Court dealt with a conflict between federal and state authority over price controls during World War II. The Federal Price Control Act of 1942 was enacted to stabilize prices and prevent inflation during wartime. However, Ohio's sheriff seized goods from a merchant for violating state law by selling at higher than federally mandated prices. The question before the court was whether Ohio could enforce its own laws that were in line with federal objectives but conflicted directly with federal enforcement procedures under the Price Control Act. The Supreme Court ruled in favor of Fleming (the administrator), stating that states cannot interfere or aid in enforcing federal regulations even if their intentions align with those of Congress; it is solely up to Congress how they wish to enforce their own legislation. This decision reinforced supremacy clause principles which assert that when there is a direct conflict between state and federal law, federal law prevails.

In the dissenting opinion for Fleming v. Rhodes, Justice Robert H. Jackson argued that the majority's decision to uphold federal price controls on intrastate transactions was an overreach of Congressional power under the Commerce Clause of the Constitution. He contended that this interpretation would allow Congress to regulate any activity it deemed might affect interstate commerce, no matter how indirect or trivial its impact may be. This could potentially lead to a dangerous expansion of federal authority into areas traditionally reserved for state regulation and control, undermining principles of federalism and states' rights enshrined in our constitutional system. Furthermore, he expressed concern about potential abuses by administrative agencies given such broad regulatory powers without sufficient checks and balances from other branches of government.