The California lawsuit challenges Trump’s efforts to repeal car emissions regulations

The state of California and the Trump administration are on track for a major legal showdown that could determine whether the state will continue to have unique powers to shape the U.S. auto market.

On Monday, California Attorney General Rob Bonta, a Democrat, filed a motion to that effect lawsuit questioning President Donald Trump’s attempt to roll back California’s vehicle emissions standards.

Since Trump took office last year, his administration has targeted California’s regulatory power to set pollution standards more stringent than federal law. The state has long enjoyed a waiver from the federal government to set its own regulations due to its role in pioneering motor vehicle emissions regulations and its unique topography that traps pollutants in major population centers.

Using unique powers granted to it under federal neat air laws, California has received more than 100 waivers from the U.S. Environmental Protection Agency over the past 50 years, most of them with little opposition. About a dozen other states, representing much of the U.S. auto market, also follow stricter emissions rules set by California regulators.

In a speech in November 2024, after Trump’s election, Bonta predicted that Trump would try to attack California’s longstanding waiver authority.

“Granting a waiver is not solely a matter of discretion on the part of EPA,” he said in an interview with Stateline. “If it is determined that California’s actions are arbitrary or capricious, these will be the only valid reasons to deny the waivers. If the Trump administration attempts to reverse them or the denial is unlawful, we will be very aggressive in taking action to protect California’s ability to seek waivers.”

Instead of outright denying the waiver, Trump’s EPA took a different approach. Earlier this month, the agency announced that it had determined that four of California’s waivers constitute rules and submitted them to Congress for review.

The Congressional Review Act, passed in 1996, requires federal agencies to submit up-to-date regulations to Congress before they take effect. Congress then has 60 business days to review these laws and can vote to repeal them.

The watchdog has rarely been invoked for 20 years, but Republicans under Trump have used it aggressively to target actions taken during the Biden administration. Congress used the act to open up mining and drilling on public lands, replacing management plans that were not previously considered reviewable policies.

Last year, Trump and Congress used the Congressional Review Act to repeal California’s electric vehicle sales mandates and diesel engine regulations, which the state challenged in court.

The Trump administration has now said California’s emissions exemptions are also regulations that could be waived by Congress. On June 12, the EPA presented Congress with four waivers for emissions from vehicles and lawn and garden equipment.

“EPA is committed to promoting consumer choice and ensuring affordable vehicles for all Americans while upholding the best interpretation of the law,” the agency said in a statement press release announcing the move.

California disputes this interpretation.

“No agency can wave a magic wand and turn an action resulting in a ruling into a rule, certainly not without a public process during which the agency confirms and explains its change in position,” the lawsuit said.

The legal battle could determine whether Republicans in Congress can quickly overturn decades of lawmaking and California’s long-standing hold on shaping the U.S. auto market. It may also determine whether Republicans’ unprecedented employ of the Congressional Review Act has unlocked a powerful up-to-date tool for environmental policy discovery.

Stateline reporter Alex Brown can be reached at: abrown@stateline.org.