Courts across the United States are increasingly grappling with federal preemption arguments as a central battleground in litigation involving regulated industries.
Once considered a largely defensive legal tool, preemption was historically raised only where a federal statute expressly barred state regulation or where state and federal requirements were in obvious conflict.
That narrower application is giving way to a broader deployment of the doctrine, as courts adopt a more expansive view of federal authority over state and local law.
Federal regulators are also growing more willing to step into litigation directly or to actively back preemption claims, adding institutional weight to arguments that were once treated as secondary concerns.
The result has been a steady accumulation of new case law reshaping how preemption is understood and applied across multiple sectors of the economy.
Last week, the Central District of California underscored this trend with its decision in California v. Wright, which denied California’s motion for a preliminary injunction.
The court held that an order issued by the Secretary of Energy under the Defense Production Act could lawfully preempt conflicting California law, marking a significant moment in the evolving doctrine.
The preemption provisions of the Energy Policy and Conservation Act, known as EPCA, are also drawing sustained attention from the energy industry and the courts overseeing it.
EPCA sets federal energy-conservation standards for appliances and expressly preempts state or local regulation of the energy efficiency, energy use, or water use of certain products under 42 U.S.C. ยง 6297(c).
The complexity of that provision has produced a divided body of case law, with courts disagreeing over exactly how far its preemptive reach extends into state and local regulatory activity.
In California Restaurant Association v. City of Berkeley, 89 F.4th 1094, the Ninth Circuit held in 2024 that EPCA preempted a municipal ordinance barring natural gas piping in new construction projects.
That ruling was seen as a broad reading of what qualifies as regulation of “energy use” under the statute, setting a precedent that resonated beyond California.
More recent decisions have begun to read the term “energy use” in EPCA more narrowly, suggesting that courts are not uniformly following the expansive approach taken in the Berkeley case.
The case Rinnai America Corp. v. South Coast Air Quality Management District, currently before the Ninth Circuit under case number 25-5129, represents one of the next major tests of how that narrower reading will develop.
Taken together, these cases signal that federal preemption has moved well beyond procedural footnote status and into a defining feature of regulatory litigation for industries subject to overlapping federal and state oversight.