Colorado on Thursday joined California and other states in suing the EPA and President Donald Trump to preserve electric vehicle sales mandates meant to clean the air and cut greenhouse gases, after Trump signed Congressional resolutions that effectively canceled the programs.
Colorado Attorney General Phil Weiser and other attorneys general sued in federal district court for northern California, calling the Congressional resolutions an illegal abuse of national powers and an attack on the well-established Clean Air Act.
The resolutions wiped out EPA waivers granted to California and copycat states to require far more clean car sales than minimums set at the federal level. Colorado’s mandate says 82% of new cars offered for sale here must have zero emissions by model year 2032.
Trump signed the resolutions in a televised ceremony Thursday morning, saying, “We officially rescue the U.S. auto industry from destruction by terminating California’s electric vehicle mandate, once and for all.” Colorado and more than a dozen other states following California’s lead had adopted clean car minimums — as well as subsequent clean heavy truck minimums.
California has received dozens of EPA waivers over the years to more effectively attack smog in Los Angeles and other cities. The state has the largest new car market in the country, and with so many other well-populated states following California’s lead, their clean air policies dominate car industry economics.
California Gov. Gavin Newsom and leaders from other states had already vowed to fight back.
“The Trump administration’s attack on clean air is breathtaking,” Weiser said in a statement Thursday. “Rolling back the federal Clean Air Act waivers through the illegal use of the Congressional Review Act is an assault on the authority of states, like Colorado, to adopt stronger tailpipe pollution limits than those set by the federal government. We’re in court to defend Colorado’s cost-effective clean car program, which was implemented to improve air quality, reduce harmful ozone pollution, and increase choices that Coloradans have when purchasing an electric vehicle.”
The Colorado Energy Office, which is overseeing many of the state’s greenhouse gas limits and electrification efforts, said the California waivers would need to be back in place if Colorado wanted to enforce its copycat targets. California’s target went slightly farther, extending the rising minimums through 2035 and saying all sales must be electric by then.
The states’ lawsuit claims the Congressional Review Act only allows Congress to overturn rules made by federal agencies, not state laws like the California and Colorado laws on electric vehicles. The lawsuit is also trying to protect California and copycat laws requiring sharp cuts to nitrogen oxide pollution and clean sales targets for heavy-duty trucks.
The EPA has in the past said congressional review does not apply to the waivers, Weiser and the attorneys general said.
“The federal government ran roughshod over federalism and separation of powers principles,” the lawsuit says. “In fact, the Congressional Review Act has never before been used in any context that resembles this one. It has certainly never been used, as it was here, to negate particular state laws.”
State leaders and environmental advocates want to cut both greenhouse gas emissions and the transportation pollution that contributes to toxic ozone, and they fear the rollbacks and a threatened erasure of federal EV tax credits will reverse years of clean air progress.
But conservatives who want more oil and gas drilling, and thought Democrats were interfering too much in the automobile markets, lauded Trump putting the finishing touches toward one of their longtime goals.
“One state’s overreach should never dictate how all Americans live, work, or drive,” said Congressional Western Caucus Vice Chair Rep. Jay Obernolte, R-California. “This bill sends a strong message that national standards should be set only in Washington, not in Sacramento.”
The American Fuel & Petrochemical Manufacturers trade group said Trump “just delivered a major win for the American people by overturning California’s gas car ban and the state’s attempt to tell consumers what they can and can’t drive.”
Colorado drivers should look at where the praise is coming from, countered Travis Madsen, transportation analyst for the nonprofit clean energy group Southwest Energy Efficiency Project. “The petroleum industry will lose sales because of electrification, so they are interested in blocking or slowing down alternatives,” he said.
Colorado has a target of nearly 1 million electric vehicles on the road by 2030, and growth of EV sales has been on pace to reach that, supporters of the mandates say. Clean vehicle sales made up 26% of Colorado’s new light-duty car market in the first three months of 2025.
Most analysts are unsure if the major auto manufacturers have gone too far down the road toward EV fleets to scrap their changeover plans.
For Colorado, Madsen said, “Fortunately, we’ve built up significant momentum. Governor Polis and state leaders have done a great job making Colorado an attractive place to drive an electric vehicle. Colorado can and should continue to drive progress — although it would be a lot easier without these new obstacles the federal government is putting in our way.”
The state energy office said the Trump administration’s actions will not stop EV momentum, but could hurt consumer choices if some manufacturers pull back.
“Colorado drivers are clear: electric vehicles are here to stay, and demand will continue to grow,” CEO director Will Toor said in a statement. “Coloradans are purchasing EVs at a rate three to four times greater than that required by rules. We anticipate growing demand for EVs in Colorado regardless of what happens with federal attempts to remove state authority to enforce clean car rules.”