New twist in the Trump-California auto fight

The Trump administration could soon move to revoke California's authority to set vehicle pollution rules that are tougher than federal standards, per multiple reports Thursday.

Why it matters: It’s the next phase in the high-stakes battle between the White House and California over carbon emissions and mileage rules and a key part of the wider White House effort to freeze Obama-era standards, rather than allowing them to get significantly tougher through the mid-2020s.

• Officials could "move within the next few days" on the vehicle pollution rules, The Wall Street Journal reports.

The intrigue: Right now California has a Clean Air Act waiver to set emissions rules (which are largely a proxy for mileage standards) that roughly a dozen other states follow.

• The administration has previously proposed yanking California's waiver as part of the complicated — and unfinished — rulemaking to roll back Obama-era mandates.
• Now, per The New York Times, Bloomberg and others, officials may decouple those plans and move against California's 2009 waiver first.

What we don't know: Why exactly the administration is reportedly separating the waiver revocation from the rule to freeze the Obama-era standards. Possibilities...

• Timing: The NYT reports the regulation to freeze the standards is "bogged down" as the administration has struggled to document "legal, technical, economic and scientific justifications."
• Legal strategy: The WSJ notes it could "insulate" the waiver revocation from the standards changes in case the latter are successfully challenged in court.
• Persuasion: Former Obama aide Jody Freeman tells Bloombergthe White House wants to dissuade more automakers from joining 4 companies — Ford, Honda, VW and BMW — that recently struck a deal with California on increasing standards for their nationwide vehicles.
• Freeman, now a Harvard law professor, said President Trump is "saying to the auto companies: ‘California has no legal authority in our opinion, so it can’t threaten to set its own standards, so you don’t need to make a deal.' "

The big picture: Automakers have chafed at Obama's rules, arguing they're too strict.

• They backed Trump's move to weaken them to some degree, but then Trump went much too far for their liking.
• Now they're desperate to avoid a split U.S. market, with one set of rules for California and a dozen other states and weaker federal standards that others follow.

But, but, but: The White House tells Axios' Alayna Treene that it's "moving forward to finalize" rules that set a "realistic and transparent fuel economy standard," and that "suggestion otherwise is false."