Also known as: federal preemption · pre-emption · preemption · federal supremacy
Written by attorneys · grounded in primary & secondary sources — see below
A constitutional doctrine under which federal statutes and regulations displace conflicting state laws pursuant to the Supremacy Clause. Federal law prevails when Congress has occupied a field or when state requirements stand as an obstacle to federal objectives.
State legislators in State A enacted a statute licensing private operators to conduct sports gambling. A federal statute barred states from authorizing such schemes. The Court held that the federal prohibition targeted legislative action rather than private conduct and therefore was invalid under the anti-commandeering doctrine.
California enacted a statute requiring insurers to disclose Holocaust-era policies. Federal executive agreements addressed the same claims through international negotiation. The state disclosure rule was preempted because it conflicted with the federal conduct of foreign affairs.
Select any source to read its text and confirm it supports the definition.
Johnson Controls barred fertile women from battery manufacturing jobs to avoid lead exposure. Federal Title VII prohibited sex-based employment discrimination. The company policy was invalid because federal antidiscrimination law preempted the state common-law tort defense asserted by the employer.
Arizona required state officers to verify immigration status during lawful stops and made unlawful presence a state crime. Federal immigration statutes occupied the field of alien registration and removal. The state provisions were preempted because they conflicted with federal enforcement discretion and objectives.
Chicago police officers conducted a warrantless search of Monroe's home. Federal civil rights law provided a damages remedy against state actors. The state law immunity defense was preempted because federal law supplied the exclusive cause of action for constitutional violations by officials.
Lopez was convicted under a federal statute for possessing a firearm near a school. Federal law regulated possession in school zones. The conviction was reversed because Congress lacked authority to enact the statute, eliminating any basis for preemption of state criminal law in the same area.
Preemption occurs when federal law regulates private conduct and displaces inconsistent state rules. Commandeering occurs when Congress orders state legislatures or officers to enact or enforce federal policy. The distinction turns on whether the federal statute targets private actors or state governmental processes.
Field preemption requires that Congress intended to occupy the entire field. Obstacle preemption applies when state law stands as an obstacle to federal objectives even if the field is not fully occupied. Courts examine statutory text, structure, and purpose to determine the scope of displacement.
State procedural requirements that do not conflict with federal substantive rules or objectives are not preempted. When the state action addresses distinct local concerns without creating an actual conflict, federal law does not displace the state requirement.
The Supremacy Clause declares the Constitution and federal laws the supreme law of the land. State laws that conflict with valid federal enactments are without effect. This hierarchy requires judges in every state to apply federal law over contrary state provisions.
…see, e. g. , Murdock v. Memphis , 20 Wall. 590 (1875); Michigan v. Long , 463 U. S. 1032 (1983), the whole jurisprudence of pre-emption, see, e. g. , Rice v. Santa Fe Elevator Corp. , 331 U. S. 218 (1947); Cipollone v. Liggett Group, Inc. , 505 U. S. 504 (1992), and many of the rules governing our habeas jurisprudence,…