Also known as:federal preemption doctrine · federal preemption · preemption · Supremacy Clause preemption
Written by attorneys · grounded in primary & secondary sources — see below
A constitutional principle under the Supremacy Clause providing that federal law supersedes conflicting state enactments. It applies when Congress intends to occupy a field exclusively or when state law stands as an obstacle to federal objectives. The doctrine does not authorize Congress to commandeer state legislative processes by directly prohibiting states from authorizing private conduct.
Sources & Authorities
How it applies
Common Examples
2
State Sports Betting Authorization Blocked
State legislators in New Jersey enacted a statute permitting licensed casinos to accept wagers on professional sports events. Federal officials invoked a statute that barred any state from authorizing such schemes and threatened enforcement against state licensing boards. The state sued, arguing the federal bar improperly targeted legislative action rather than private betting conduct. The court held the federal statute invalid because it commandeered state processes instead of regulating private parties directly.
State Unfair Competition Claim Survives
Dawson Steel developed a novel boat hull design and sold it without obtaining a federal patent. A competitor copied the design exactly and marketed identical hulls at lower prices. Dawson sued in state court under an unfair competition statute that protected unpatented designs from direct copying. The court permitted the claim to proceed because the state remedy addressed deceptive conduct without creating patent-like exclusivity that would conflict with federal patent policy.
Put it into practice
Test Yourself
10
Practice Questions5
· 1 primary source
Select any source to read its text and confirm it supports the definition.
Cases
Study Supplements
Common questions
Frequently Asked
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When does federal law preempt a state statute under the Supremacy Clause?+
Federal law preempts when Congress occupies an entire field or when state law obstructs federal objectives. Preemption does not occur merely because a federal statute mentions state action. The federal measure must regulate private conduct rather than command state legislatures.
Supporting sources
Does the doctrine of federal preemption allow Congress to order states to enact or refrain from enacting specific laws?+
No. The doctrine forbids Congress from commandeering state legislative processes. A federal statute that directly prohibits states from authorizing private activity is invalid under the anti-commandeering principle even if framed as preemption.
Supporting sources
TortsProducts liability based on the design, manufacture, and distribution of products and defenses to such claims · Products liability based on the design, manufacture, and distribution of products and defenses to such claimsNEXTGENIntermediate