Trump administration sues California over its car emission rules

Federal government takes California to court

The Trump administration sued California on March 12 to block the state from enforcing its own vehicle emission and zero-emission vehicle rules.

The Justice Department filed the lawsuit on behalf of the National Highway Traffic Safety Administration (NHTSA), targeting the California Air Resources Board (CARB).

Attorney General Pam Bondi said California’s policies drive up costs for consumers and break federal law.

NHTSA Administrator Jonathan Morrison said the suit will help automakers follow one national standard instead of a patchwork of state rules.

DOJ says California overstepped federal law

The federal government argues California’s rules violate a 1975 law called the Energy Policy and Conservation Act, which gave NHTSA sole authority to set fuel economy standards nationwide.

The key claim is simple: rules that limit tailpipe CO2 are really fuel economy rules in disguise, because burning less fuel means less CO2.

Under that argument, California’s zero-emission vehicle targets amount to a state-level fuel economy mandate.

The lawsuit asks a federal court to strike down all of California’s zero-emission rules and permanently block enforcement.

Rules would end gas car sales by 2035

California’s Advanced Clean Cars II program, adopted by CARB in 2022, requires that about 35% of new cars sold in the state for the 2026 model year produce zero emissions.

That target jumps to roughly 68% by 2030 and 100% by 2035, which would effectively end the sale of new gas-powered cars in the state.

This lawsuit goes further than past actions by also targeting older, less strict emission standards that CARB says still apply.

This suit goes beyond past moves

In June 2025, President Trump signed three Congressional Review Act (CRA) resolutions that revoked EPA waivers for California’s newer, more aggressive rules. But those actions only covered the latest standards.

This new lawsuit goes after even the older rules California has been enforcing while the legal fight over the CRA actions plays out.

The federal government now argues California has no legal authority to enforce any of its own vehicle emission or zero-emission vehicle rules, old or new.

California earned its authority decades ago

California has had the right to set its own vehicle emission rules since before the federal Clean Air Act of 1970, because the state had severe smog problems that came before federal regulation.

Under Section 209 of the Clean Air Act, the EPA can grant California a waiver to adopt standards stricter than federal ones.

Other states can then choose to follow California’s lead. During Trump’s first term, his administration revoked that authority.

President Biden’s EPA reinstated it in 2022 and granted new waivers for the Advanced Clean Cars II program in December 2024.

Kiley proposed a rare tool to revoke waivers

Rep. Kevin Kiley of California proposed using the Congressional Review Act to overturn the Biden-era waivers.

But the Government Accountability Office, a nonpartisan congressional watchdog, determined the CRA could not legally apply to waivers because they are orders, not rules.

The Senate Parliamentarian reached the same conclusion. Senate Republicans voted on party lines to override those findings and passed the resolutions anyway.

Trump signed all three CRA resolutions on June 12, 2025.

California and 10 states filed suit the same day

The same day Trump signed the CRA resolutions, California Attorney General Rob Bonta led a coalition of 11 states in filing a federal lawsuit challenging them.

States joining California included Colorado, Delaware, Massachusetts, New Jersey, New Mexico, New York, Oregon, Rhode Island, Vermont, and Washington. California argues the CRA was never meant to apply to waiver decisions.

Gov. Gavin Newsom also signed an executive order that day directing CARB to develop new zero-emission rules while the legal battle continues.

That lawsuit remains pending in Northern California.

EPA also rolled back its own emission rules

One month before this new lawsuit, the EPA took a major step of its own.

On Feb. 12, the agency rescinded its 2009 Endangerment Finding, which had classified greenhouse gases as a threat to public health.

That finding served as the legal basis for all federal vehicle greenhouse gas emission standards since 2009. The EPA also repealed all federal greenhouse gas emission standards for cars and trucks.

The administration called it the largest deregulatory action in U.S. history. Environmental groups and states have filed lawsuits challenging the move.

Newsom fires back at the administration

Gov. Newsom’s office criticized the lawsuit, pointing out that it came as gas prices climbed nationwide because of the Iran conflict.

A spokesperson said the administration was attacking California for trying to give residents cheaper options by encouraging electric vehicles.

CARB has maintained that its emission standards protect public health in a state with some of the worst air pollution in the country.

California says its vehicle rules target pollution, not fuel economy, and that the Clean Air Act gives the state the right to act.

Eighteen jurisdictions could lose their rules too

Seventeen states and Washington, D.C., have adopted California’s vehicle standards to varying degrees under Section 177 of the Clean Air Act.

Together with California, those jurisdictions account for roughly 40% of new car sales in the country. If California loses the right to set its own standards, those states would lose the option of following California’s rules.

That means the outcome could change what kinds of cars are available and how much they cost for tens of millions of Americans far beyond California’s borders.

Car buyers won’t see changes right away

For people shopping for a car right now, nothing changes immediately. The lawsuit will take time to work through the courts.

If the federal government wins, automakers would only need to meet one national standard, which could mean fewer EV models in states that now follow California.

If California wins, stricter state-level rules would continue. The auto industry has sent mixed signals, with some manufacturers pushing for a single national standard and others investing heavily in electric vehicles.

Multiple cases could reach the Supreme Court

Several lawsuits are now playing out at the same time: the states’ challenge to the CRA revocations, challenges to the EPA’s Endangerment Finding decision, and now this new NHTSA lawsuit against CARB.

Legal experts widely expect these disputes to eventually reach the Supreme Court. The case has landed in a U.S. District Court of California.

The central question is whether one state can set vehicle standards that end up shaping the national auto market, or whether only the federal government holds that power.

This article was created with AI assistance and human editing.

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