The ongoing saga of President Trump vs. the Golden State took yet another bizarre turn late Monday when the administration threatened to withhold highway funding from California, claiming the state has failed to demonstrate what steps it is taking to improve air quality. 

Believe it or not, this isn't a joke. 

In a letter sent to the California Air Resources Board, EPA Administrator Andrew Wheeler said, among other things, that the state has failed in its duties as laid out in the Clean Air Act and needs to supply an updated plan or risk forfeiting its federal highway funding, The Washington Post reports.

Wheeler's letter points out that 34 million Californians live in zones that don't meet the standards for clean air. According to the paper, California has more than 130 separate measures intended to improve air quality currently awaiting federal approval. The EPA has the power to reject those plans and deny the state would could potentially be billions of dollars in federal highway aid.

"This letter appeared only days after EPA attacked our state authority on cars, increasing air pollution while at the same time limiting our ability to reduce it," said CARB Executive Officer Richard Corey in a statement.

Last Wednesday, the administration announced that it plans to revoke the waiver permitting California to set its own fuel efficiency standards above and beyond those enforced at the federal level, even after 17 automakers laid out their concerns that a federal challenge of the California rules wouldn't be in their interest. 

This latest move by the Trump administration illustrates the gulf between federal regulation and common-sense understanding of California's aggressive regulation of vehicle emissions. By revoking California's authority to set its own requirements for greenhouse-gas emissions and fuel efficiency, the EPA is effectively taking away the state's primary emissions-control tool with one hand while punishing it for lack of action with the other.

At this point, it appears inevitable that this battle will continue to escalate until it reaches the Supreme Court or a new administration takes power in Washington, whichever comes first.