Express preemption is the form of federal preemption in which a statute contains explicit language stating that it overrides state or local law on a defined subject. Unlike other forms of preemption that a court has to infer from the structure of a federal scheme or from a conflict between two rules, express preemption is written into the statute itself. Its authority comes from the Supremacy Clause of the U.S. Constitution, and it appears in laws governing everything from employee benefits and medical devices to cigarettes, air travel, and national banking.
The Constitutional Source
Express preemption rests on Article VI, Clause 2 of the Constitution. That provision makes the Constitution, federal statutes, and treaties “the supreme Law of the Land” and binds state judges to follow them regardless of anything in state law to the contrary.1Congress.gov. Article VI Clause 2 Supremacy Clause Without that constitutional hierarchy, a preemption clause would be a suggestion.
When Congress writes an express preemption provision, the Supremacy Clause gives it the force to displace state law. Because the constitutional authority is settled, express preemption disputes are almost always questions of statutory interpretation. The fight is about what Congress actually preempted, not whether it had the power to preempt.
How to Recognize It in a Statute
Congress signals express preemption through specific phrases. The wording varies, but a few patterns recur.
One common formulation bars states from establishing or continuing any requirement that is “different from, or in addition to” the federal standard.2Office of the Law Revision Counsel. 21 USC 360k – State and Local Requirements Respecting Devices Another declares that a federal act “shall supersede any and all State laws” that relate to a covered subject.3Office of the Law Revision Counsel. 29 USC 1144 – Other Laws A third type says that no requirement or prohibition “shall be imposed under State law” in the regulated area.4Office of the Law Revision Counsel. 15 USC 1334 – Preemption
The presence of one of these clauses is what separates express preemption from its implied counterparts. When a statute contains explicit preemption language, the Supreme Court has said courts “need only identify the domain expressly pre-empted” by the provision.5Legal Information Institute. Cipollone v. Liggett Group, 505 U.S. 504 (1992) That phrasing understates the difficulty. Figuring out what falls inside that domain is where most of the litigation happens.
Floor Preemption Versus Ceiling Preemption
Not every express preemption clause operates the same way. The most consequential variation is whether the federal standard functions as a floor or a ceiling.
Floor preemption sets a minimum. States can still legislate in the area, as long as their rules meet or exceed the federal baseline. Many environmental and workplace safety statutes follow this pattern, and a statute using this approach may say that its provisions do not preempt more stringent local regulation.
Ceiling preemption is more restrictive. It bars states from imposing requirements that differ from or go beyond the federal rule. Language stating that no state “may establish or continue in effect” any requirement that differs from the federal one typically creates a ceiling. The medical device preemption clause is a textbook example: states cannot impose safety or effectiveness requirements that differ from what the FDA has established for an approved device.2Office of the Law Revision Counsel. 21 USC 360k – State and Local Requirements Respecting Devices
Under a floor, a state that wants stronger consumer protections can enact them. Under a ceiling, even carefully drafted state regulation is blocked. When a statute is silent or ambiguous about which type it creates, courts have to decide.
Savings Clauses
Many statutes with express preemption clauses also include a savings clause, and the interaction between the two produces some of the hardest interpretive questions in this area. A savings clause carves out an area that the preemption clause does not reach, typically preserving certain state laws or common-law remedies that would otherwise be displaced.
ERISA illustrates the pattern. Its preemption clause sweeps across state laws relating to employee benefit plans, but its savings clause exempts state laws that regulate insurance, banking, or securities.3Office of the Law Revision Counsel. 29 USC 1144 – Other Laws The National Traffic and Motor Vehicle Safety Act preempts state safety standards for motor vehicles that differ from federal standards, but its savings clause preserves common-law liability claims.
Courts treat savings clauses as evidence that Congress recognized the preemption clause could be read broadly and deliberately chose to protect some state-law remedies from that breadth. In Sprietsma v. Mercury Marine (2002), the Supreme Court pointed to a savings clause in the Federal Boat Safety Act as support for the conclusion that the preemption clause did not extend to common-law claims.6Congress.gov. Federal Preemption – A Legal Primer A preemption clause read alone might look like it wipes out all state law on a subject. A savings clause pulls some of that authority back.
Examples Across Major Federal Statutes
Express preemption operates across many industries, and each statute uses its own formulation.
ERISA
ERISA contains one of the broadest preemption clauses in federal law. It provides that the statute “shall supersede any and all State laws insofar as they may now or hereafter relate to any employee benefit plan.”3Office of the Law Revision Counsel. 29 USC 1144 – Other Laws Congress included this language so that employers operating in multiple states could run a single benefit plan rather than navigate fifty different regulatory regimes. The phrase “relate to” has been interpreted expansively.
Medical Device Amendments
The Medical Device Amendments bar states from imposing any requirement on a medical device that is “different from, or in addition to” a federal requirement, where that requirement relates to safety or effectiveness.2Office of the Law Revision Counsel. 21 USC 360k – State and Local Requirements Respecting Devices The statute allows states to apply for an exemption if their requirement is more stringent and justified by compelling local conditions. Absent that exemption, once the FDA has imposed requirements on a device, state regulation of the same ground is displaced.
Federal Cigarette Labeling and Advertising Act
This Act bars states from imposing any requirement or prohibition “based on smoking and health” with respect to cigarette advertising or promotion, so long as the packaging conforms to federal labeling rules.4Office of the Law Revision Counsel. 15 USC 1334 – Preemption The clause played a central role in decades of tobacco litigation.
Airline Deregulation Act
The Airline Deregulation Act prevents states from enacting or enforcing any law “related to a price, route, or service of an air carrier.”7Office of the Law Revision Counsel. 49 USC 41713 – Preemption of Authority Over Prices, Routes, and Service The language reaches beyond statutes and administrative regulations to include state common-law claims that effectively regulate airline pricing or services. A parallel framework was later extended to motor carriers transporting property, with a narrow exception for state motor vehicle safety authority.
National Bank Act
The National Bank Act allows a national bank to charge interest at the rate permitted by the state where the bank is located.8Office of the Law Revision Counsel. 12 USC 85 – Rate of Interest on Loans, Discounts and Purchases A national bank headquartered in a state with generous rate laws can charge those rates to borrowers in other states, effectively overriding local usury caps. This “interest rate exportation” reshaped the credit card and consumer lending industries.
Effect on Private Lawsuits
Express preemption does not just block state legislation. It can also bar state-law tort claims by injured individuals against manufacturers. When a court finds that a preemption clause covers common-law claims, a plaintiff who might otherwise sue for negligence or failure to warn loses that avenue.
Cipollone v. Liggett Group (1992)
The Supreme Court set the framework for this analysis in Cipollone v. Liggett Group. The case involved state-law claims against cigarette manufacturers, and the Court held that the 1969 amendments to the Cigarette Labeling Act preempted certain common-law claims. The reasoning: a damages award effectively imposes a state “requirement” on the manufacturer, and if that requirement relates to smoking and health disclosures, it falls within the preemption clause.5Legal Information Institute. Cipollone v. Liggett Group, 505 U.S. 504 (1992) The Court also directed that express preemption provisions be construed narrowly, in light of the presumption against preemption.
Medtronic v. Lohr (1996) and Riegel v. Medtronic (2008)
Two medical device cases show that the scope of express preemption depends on how specific the underlying federal requirements are. In Medtronic, Inc. v. Lohr, the Court held that the Medical Device Amendments did not preempt state tort claims against a device cleared through the FDA’s 510(k) process, because that pathway focuses on substantial equivalence and does not impose specific device-level requirements.9Library of Congress. Medtronic, Inc. v. Lohr, 518 U.S. 470 (1996)
Twelve years later, the Court reached the opposite result for a device that had gone through premarket approval. In Riegel v. Medtronic, the Court held that the preemption clause bars common-law claims challenging the safety or effectiveness of a PMA-approved device, because the PMA process does impose specific federal requirements that state-law claims would alter or add to.10Justia. Riegel v. Medtronic, Inc., 552 U.S. 312 (2008) The Court left one important opening: state claims premised on a violation of FDA regulations survive, because they parallel rather than add to federal requirements.
The takeaway: generic regulatory clearance often will not trigger preemption of tort claims; detailed, device-specific approval often will.
The Presumption Against Preemption
Even when a statute contains an express preemption clause, courts do not automatically give it the widest possible reading. In areas traditionally regulated by the states, such as health, safety, and welfare, the Supreme Court applies a presumption against preemption. The rule originated in Rice v. Santa Fe Elevator Corp. (1947), where the Court said that when “Congress legislated here in a field which the States have traditionally occupied,” state police powers “were not to be superseded by the Federal Act unless that was the clear and manifest purpose of Congress.”11Justia. Rice v. Santa Fe Elevator Corp., 331 U.S. 218 (1947)
The presumption works as a thumb on the scale. When a preemption clause could be read two ways, the narrower reading wins. If federal and state law can coexist under a plausible reading, courts favor that one over one that displaces state authority.12Legal Information Institute. New Deal and Presumption Against Preemption Clear statutory text still controls. The presumption matters most in borderline cases where the reach of a clause is genuinely debatable.
How It Differs From Implied Preemption
Federal law can override state law in two other ways, and the distinction matters because it changes how a court analyzes the dispute. Field preemption applies when federal regulation of a subject is so comprehensive that it leaves no room for state law to operate, even without a direct conflict. Courts infer that Congress meant to occupy the field. Conflict preemption applies when a state law directly contradicts federal law, either by requiring something federal law forbids or by making compliance with both impossible.
With express preemption, a court starts and usually ends with the preemption clause itself. With implied preemption, a court has to reconstruct congressional intent from the structure of the statute, its regulatory history, and the nature of the conflict. Express preemption cases still produce plenty of litigation over the scope of the clause, but the analysis begins with concrete text rather than inference.