# Dual Federalism **Status: stub — expand.** The model in which federal and state governments occupy **separate and mutually exclusive** spheres, each supreme within its own — the "layer cake." Dominant from roughly the 1830s to 1937. Its doctrinal machinery: a narrow reading of the [[Commerce Clause]] limited to actual movement across state lines, the [[Tenth Amendment]] treated as an affirmative reserved-powers limit rather than a truism, and a robust state [[Police Power]] insulated from federal reach. *Hammer v. Dagenhart* (1918), striking a federal child-labor law, is the emblem. It collapsed in the New Deal — *NLRB v. Jones & Laughlin* (1937) and [[Wickard v. Filburn]] (1942) — and was replaced by [[Cooperative Federalism]]. The label matters because dual federalism is what "states' rights" arguments usually mean to restore, and because the Rehnquist-era revival ([[United States v. Lopez]], [[Printz v. United States]]) recovered pieces of it without restoring the model. ## See also - [[Cooperative Federalism]] · [[States' Rights]] · [[Federalism Powers Crosswalk]]