California has functioned as a de facto national emissions regulator for years, a consequence of manufacturers building to the state's strict standards rather than engineering a separate version for the rest of the country. Now four Senate Republicans are trying to sever that mechanism at the root, using the Congressional Review Act to rescind the EPA waivers they say made it possible. How much of that foundation actually comes apart is the harder question.
The legal mechanism under attack
The effort is led by Senators Cynthia Lummis of Wyoming, Eric Schmitt of Missouri, Jon Husted of Ohio, and Pete Ricketts of Nebraska. Lummis, a top member of the Senate Environment and Public Works Committee, is the package's lead architect.
The Congressional Review Act gives Congress the power to nullify agency rules and, critically, bars agencies from issuing rules that are "substantially the same" without fresh congressional authorization. Republicans argue that using the CRA here would prevent future administrations from reinstating the waivers through the same procedural path. The Clean Air Act carved out an exception for California in the 1960s, allowing the state to seek EPA waivers for emissions rules stricter than federal standards. The original rationale was Los Angeles smog. Republicans argue that exception has since been extended far beyond its purpose, turning a localized air quality tool into nationwide climate regulation that bypassed Congress entirely.
What each resolution targets
Lummis's resolution takes aim at a 2025 EPA waiver issued just before President Trump took office, which allowed California to phase out new gas-powered small engines: chainsaws, leaf blowers, and lawn mowers. Schmitt's resolution targets a waiver granted shortly after George W. Bush left office that lets California enforce greenhouse gas emissions standards on new passenger vehicles beginning with the 2009 model year. Husted seeks to rescind a 2022 waiver that restored California's Advanced Clean Cars program authority. Ricketts is going after an Obama-era waiver that originally authorized that same program.
Together the four resolutions go further than last year's effort, when Congress rescinded three Biden-era waivers covering trucks, cars, and buses. This round targets the earlier authorizations that Republicans say created the regulatory foundation for those now-dead rules.
Two industry groups back the package. Andrew Bray of the National Association of Landscape Professionals said his members support a responsible transition to lower-emission equipment but argued it must come from practical innovation, not government mandates. Michael Lee of the Golf Course Superintendents Association of America said the legislative process, not state-specific decisions with nationwide consequences, is the correct venue.
The counterargument
Opponents are expected to argue the effort would undermine California's longstanding authority under the Clean Air Act to adopt stricter environmental standards. That argument carries real legal weight. The California carve-out has decades of statutory precedent behind it, and courts have historically been reluctant to strip states of authority that Congress explicitly granted. Whether the CRA can permanently foreclose a statutory exception, rather than simply rescind individual waivers issued under it, is a question no court has fully resolved.
On balance
The case for congressional action rests on an observable market reality: one dominant buyer's standards become the national standard when manufacturers produce a single product line. The risk is that the CRA is being stretched to do work it was not designed for, and litigation would follow quickly. The line to watch is whether these resolutions clear the Senate and whether the administration signals it will not pursue the same waivers through separate channels. Schmitt's target, the waiver covering greenhouse gas standards for the 2009 model year and beyond, is the oldest in the package and the hardest to unwind without years of court review.