Except that last May the "Waiver/exemption" in the Clean Air Act that CA used was essentially "nullified" by Congress (while both chambers ignored their internal watchdog insistence that it couldn't be done that way) -
https://www.democraticunderground.com/10143451497
Trump signs measure to block California car standards, says it will 'rescue' automakers
Todd Spangler, Detroit Free Press
Thu, June 12, 2025 at 7:42 PM EDT
President Donald Trump has signed a congressional resolution reversing a waiver previously granted to California and other states that would have let them ban the sale of gasoline-powered cars, trucks and sport-utility vehicles.
At a ceremony at the White House on June 12, Trump said the resolution has the force of law and suggested it can't be challenged in court. But California officials and a coalition of officials from other states on the same day did just that, arguing it was passed in the U.S. House and Senate under a process they say violated existing law.
By signing the resolution, Trump continued to deliver on his promise to tear down rules and regulations promoting the adoption of electric vehicles (EVs) nationwide which he and other Republicans argue amounted to a mandate on American consumers regarding which cars and trucks they may buy.
The signing also happened as Trump and California Gov. Gavin Newsom continue to spar over Trump's decision to send thousands of National Guard members and some 700 Marines to that state in support of efforts to respond to protests against immigration enforcement by the Trump administration. No such military intervention has been ordered into a state by the federal government without the state's request since the 1960s. Trump said the California waiver, which is provided for under the Clean Air Act, "has been a disaster for this country." He added that by signing the resolution, he was moving to "rescue the American auto industry."
(snip)
California (and other states) then sued -
California sues Trump for blocking its clean-air rules for cars, trucks and vows to set new mandates
https://www.democraticunderground.com/10143477430
As far as I know, it's still in court.