426 U.S. 833 (1976), argued 16 Apr. 1975, reargued 2 Mar. 1976, decided 24 June 1976 by vote of 5 to 4; Rehnquist for the Court, Blackmun concurring, Brennan, White, Marshall, and Stevens in dissent. National League of Cities struck down a 1974 federal statute that extended the maximum hours and minimum wage provisions of the Fair Labor Standards Act to most state and municipal employees. That the maximum hours and minimum wage provisions of the Fair Labor Standards Act were constitutional as applied to the employees of private corporations was a matter of settled law. However, the Court, seemingly breathing new life into the Tenth Amendment, held that as applied to the “states as states,” the provisions were an unconstitutional interference with an essential “attribute of sovereignty attaching to every state government” (p. 845), and thus violated the Tenth Amendment.
The significance of National League of Cities lay not so much in the actual impact of the decision itself, but in its symbolic blow in favor of federalism. By invoking the Tenth Amendment as a serious barrier to federal power, the Court revived a provision that had been dormant since the New Deal. The Court struck down the statute in question not because Congress lacked the affirmative power to pass it—the regulation clearly fell under Congress's power to regulate interstate and foreign commerce—but because the act violated “traditional aspects of state sovereignty” and “impermissibly interfere[d] with the integral governmental functions” of the states (pp. 849, 851). For the first time since the New Deal, the Supreme Court had struck down a federal law on the ground that Congress had transgressed the permissible boundaries of federalism.
National League of Cities did not challenge Congress's power to regulate private corporations or individuals involved in interstate commerce or in activities that had a substantial effect on interstate commerce. The decision affected only those cases in which the states themselves—that is, the state governments or their political subdivisions—were so engaged. The Court held that “the States as States stand on a quite different footing from an individual or a corporation when challenging the exercise of Congress’[s] power to regulate commerce” (p. 833). In so holding, the Court overruled Maryland v. Wirtz (1968) but left intact the long line of decisions granting broad congressional powers to regulate interstate and foreign commerce.
National League of Cities left unclear exactly where to draw the line between permissible and impermissible federal intrusions on the states. Justice William Rehnquist's formulation of the test varied from “functions essential to separate and independent existence” to “traditional aspects of state sovereignty” to “integral governmental functions” and “traditional operations of state and local governments.” As examples of traditional or integral governmental functions the Court listed fire prevention, police protection, sanitation, public health, and parks and recreation. Since National League of Cities itself involved a general challenge to the sweeping provisions of the 1974 act, specific determinations of what constituted a traditional governmental function were left to later cases involving more specific congressional actions.