Article VI, Clause 2:

This Constitution, and the Laws of the United States which shall be made in Pursuance thereof; and all Treaties made, or which shall be made, under the Authority of the United States, shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding.

The Supreme Court abandoned dual federalism during the New Deal era of the 1930s and 1940s. In those years, the Court acceded to demands for a more active national government by revising its Commerce Clause and Tenth Amendment jurisprudence.1 The federal government thereby gained vast new powers to regulate the economy, which it deployed in new and creative ways.2 But this expansion of federal authority threatened sweeping consequences when paired with the Court’s aggressive application of the Supremacy Clause. Specifically, if field preemption automatically followed from many types of federal legislation, Congress’s enhanced powers would displace large swathes of state regulation—even in cases when state regulation did not conflict with federal law. To avoid this outcome, the New Deal Court retreated from dual federalist notions of “latent exclusivity,” clarifying that federal law displaced state law only if Congress’s intention to do so was clear.

In Mintz v. Baldwin, for example, the Court rejected the argument that a federal law regulating the inspection and transportation of cattle superseded a state order compelling certain breeders to remove uncertified cattle from the state.3 In rejecting this argument, the Court explained that “[t]he purpose of Congress to supersede or exclude state action against the ravages of disease is not lightly to be inferred,” and that “[t]he intention so to do must definitely and clearly appear.” 4 The Court endorsed a similar principle in Rice v. Santa Fe Elevator Corp., where it held that the federal Warehouse Act superseded some—but not all—state law claims against grain-warehouse operators.5 The Court explained that, in evaluating whether federal law displaces state law, it “start[ed] with the assumption that the historic police powers of the States were not to be superseded . . . unless that was the clear and manifest purpose of Congress.” 6 The Court continues to apply this “presumption against preemption” to this day-albeit in limited circumstances.7

Footnotes

1

See Wickard v. Filburn, 317 U.S. 111, 125 (1942) (holding that Congress’s Commerce Clause authority extends to intrastate activities that in the aggregate “exert[ ] a substantial economic effect on interstate commerce” ); United States v. Darby, 312 U.S. 100, 119–24 (1941) (upholding the Fair Labor Standards Act as a permissible exercise of the Commerce Power that did not violate the Tenth Amendment); NLRB v. Jones & Laughlin Steel Corp., 301 U.S. 1, 49 (1937) (upholding the National Labor Relations Act as a permissible exercise of the Commerce Power).

2

See, e.g., 2 Bruce Ackerman, We the People: Transformations 281–311 (1998).

3

289 U.S. 346, 350 (1933).

4

Id. at 350.

5

331 U.S. 218, 230–37 (1947).

6

Id. at 230.

7

See ArtVI.C2.3.4 Modern Doctrine on Supremacy Clause.