A coalition of states led by California filed a lawsuit Friday against the Trump administration, challenging its decision to revoke a rule that empowers the state to set tougher car emissions standards than those required by the federal government.

The lawsuit seeks to defend California and the 13 other states that follow its car pollution rules from the administration’s latest effort to loosen environmental regulations. It maintains that the special waiver the state has relied on for the last 50 years to set its own standards is not only lawful but essential to protecting California’s air quality and preventing the worst effects of climate change.

Attorneys general from 22 other states and the District of Columbia joined the lawsuit, as did the cities of New York and Los Angeles. The list includes states that have adopted California’s more stringent car emissions rules, such as New Jersey, New York, Pennsylvania, Washington and Oregon. It also includes several states — Michigan, Wisconsin and North Carolina — that Trump won in 2016.

The administration’s plan to revoke the waiver is likely to set off years of legal battles that could eventually land at the U.S. Supreme Court. California Atty. Gen. Xavier Becerra said in a statement Friday that the administration was attempting to resurrect previously unsuccessful legal arguments to justify its position.


“Two courts have already upheld California’s emissions standards,” Becerra said in a statement. “Yet, the Administration insists on attacking the authority of California and other states to tackle air pollution and protect public health.”

The lawsuit, California vs. Chao, was filed against the National Highway Traffic Safety Administration, which has been working with the Environmental Protection Agency on a proposal to weaken fuel efficiency standards put in place under the Obama administration.

These regulations require automakers to build increasingly efficient vehicles so that by 2025 the nation’s cars and trucks would average more than 50 miles per gallon. Under Trump, the agencies have proposed freezing mileage targets at about 37 mpg for cars after 2020.

Though the announcement of that rollback was initially supposed to coincide with the administration’s effort to dismantle California’s standards, the two were ultimately separated. A few months after California spurned the White House by secretly negotiating a deal with four major automakers to increase fuel efficiency and reduce emissions, the Trump administration decided to fast-track plans to revoke the state’s authority to set stricter standards.


At a news conference Thursday at EPA headquarters in Washington, Transportation Secretary Elaine Chao said the administration was stripping California of its power to set auto emissions rules because the state’s regulations made new cars unaffordable.

“We will not let political agendas in a single state be forced on the other 49,” Chao said.

The administration has argued that lower car prices will encourage drivers to replace their older vehicles with safer, more efficient ones — an assertion that California leaders and independent scientists have refuted.

In fact, even the EPA’s experts have written that the Trump administration’s proposal would be “detrimental to safety, rather than beneficial.”


This has led critics to speculate that the administration’s assault on California’s waiver has more to do with scoring political points against a frequent adversary than improving driver safety.

California has sued the administration repeatedly over its agenda of dismantling Obama-era environmental and public health regulations. Federal judges have sided with California and environmental groups in cases concerning air pollution, pesticides and the royalties that the government receives from companies that extract oil, gas and coal from public land.

California’s special authority to go further than the federal government in regulating auto pollution dates to the 1960s, when Los Angeles was enveloped in a thick layer of smog that state officials came to see as a public health crisis. By the time the 1970 federal Clean Air Act took effect, the state had already enacted its own tailpipe emission controls.

Concerned that each state would pass different regulations, Congress decided that the EPA would set vehicle pollution standards for the nation. But it carved out an exception for California, saying that the EPA would be required to grant the state a waiver to set its own rules, provided they were at least as stringent as the federal ones. Other states could choose to follow either California’s regulations or those set by the EPA.


Because of its unique power to set emissions rules, California has served as a laboratory for tough new auto pollution regulations and has worked to promote the adoption of electric vehicles. The administration’s action jeopardizes the state’s mandate that automakers sell more zero-emission vehicles and plug-in hybrids and raises new doubts about whether it will be able to meet its goal of having more than 1 million such vehicles on the road by 2025.

Lawyers and environmental policy experts said the administration’s move is unprecedented.

“EPA has never revoked any of the 50-plus waivers that it has granted to California, and there is no legal basis for doing so,” said Jeff Alson, a former EPA senior engineer and policy advisor who retired in 2018.