The U.S. Senate voted May 22, 2025 to repeal three California waivers to the Clean Air Act, including the waiver that allows the state to end the sale of new gasoline-fueled or diesel-fueled passenger cars and trucks by 2035. The Senate voted 51-44 with only one Democrat joining to repeal the waivers and four senators not voting. The U.S. House of Representatives passed the three resolutions earlier in the month, and the bill is now awaiting President Donald Trump’s signature.
The Clean Air Act (CAA) authorizes California to request waivers from the law’s emissions standards in order to set its own, higher emissions standards. The California emissions standards have national implications. Under the Clean Air Act, other states can adopt California’s standards. In this case, 11 other states were to follow California’s plan to end the sale of new gas-powered cars by 2035, accounting for about 40 percent of the U.S. auto market, according to the New York Times. Automakers have protested the California regulations and urged Congress to overturn them.
Senate Majority Leader John Thune said the waiver for the Advanced Clean Cars II rule, which was issued in December 2024, was “an attempt by the Biden administration to impose an electric-vehicle mandate across this country.”
On his first day in office, President Trump signaled his intention to review California’s emissions waivers in an executive order that established that it is U.S. policy to “eliminate the ‘electric vehicle (EV) mandate,” which involves terminating “state emissions waivers that function to limit sales of gasoline-powered automobiles.”
The Senate resolutions overturn the following waivers:
H.J. Res. 87 would overturn the waiver for the Advanced Clean Trucks (ACT) regulation, which requires truck manufacturers to sell zero-emission trucks as an increasing percentage of their annual California sales from 2024 to 2035.
H.J. Res. 88 would overturn the waiver for the Advanced Clean Cars II rule, which requires the phase-out of the sale of new gasoline-fueled or diesel-fueled passenger cars and trucks by 2035.
H.J. Res. 89 would overturn the Heavy-Duty Omnibus rule, which establishes more stringent emissions standards for heavy-duty engines, including reducing NOx emissions by 90%.
Congressional Review Act Controversy
The Senate repealed the waivers under the Congressional Review Act (CRA), which requires agencies to submit rules to both houses of Congress and the U.S. Government Accountability Office (GAO) before the rules may take effect. Under the CRA, Congress can overturn certain federal agency actions by issuing a joint resolution of disapproval within 60 days of a continuous session that begins when the rule has been published in the Federal Register and been received by Congress. Republicans argued that the waivers were rules that they can repeal under CRA by a simple majority vote and not by the 60-vote majority required to defeat the filibuster.
The Senate’s action brought controversy that could have a lasting impact. The Congressional Research Service earlier stated that California’s CAA emissions waivers cannot be reviewed under the CRA because a waiver is not a rule as defined in the CRA. The GAO also issued an opinion stating that California’s emissions waiver is not a rule “for purposes of CRA and, thus, not subject to the requirement that it be submitted to Congress and the Comptroller General before it may take effect.”
Some Republicans were concerned that disregarding the parliamentarian’s ruling would create a precedent that could allow Democrats to undo Trump decisions in the future. Prior to the vote, Democrats warned of the potential impact of this action.
“Republicans should think twice before moving ahead with this unprecedented overreach. If they invoke this nuclear option now, they should expect that a future Democratic government will have to revisit decades worth of paltry corporate settlements, deferred prosecution agreements, and tax rulings that were overly favorable to multinationals and ultra-wealthy individuals. That would only be the beginning. These partisan actions cut both ways,” Senator Ron Wyden said in a statement.
Lawsuits Likely
California Governor Gavin Newsom and Attorney General Rob Bonta said they will sue the Trump administration over the repeal, arguing that the Republicans are misusing the authority under the Congressional Review Act.
“This Senate vote is illegal,” Governor Gavin Newsom said in a statement. “Republicans went around their own parliamentarian to defy decades of precedent. We won’t stand by as Trump Republicans make America smoggy again — undoing work that goes back to the days of Richard Nixon and Ronald Reagan — all while ceding our economic future to China. We’re going to fight this unconstitutional attack on California in court.”
California’s Potential Policy Routes
California policymakers could still pursue a number of routes in pursuit of their EV goals. The California Air Resources Board (CARB) could develop new emissions rules under a future Democratic administration. The state could also use additional incentives for EVs as well as taxes on the use of fossil fuels.
California could also negotiate with automakers to adopt stricter emissions standards. In 2019, CARB and five automakers agreed to adopt vehicle emissions standards that were stricter than those proposed by the Trump administration.