Workers inspecting vehicles at a General Motors assembly line in Flint, Mich.
Credit: Jeff Kowalsky/Bloomberg/ Getty

Breaking with some of their biggest rivals, General Motors, Fiat Chrysler and Toyota said Monday they were intervening on the side of the Trump administration in an escalating battle with California over fuel economy standards for automobiles.

Their decision pits them against leading competitors, including Honda and Ford, who this year reached a deal to follow California’s stricter rules. It represents the latest twist in one of the Trump administration’s most consequential rollbacks of regulations designed to fight climate change. It has also opened a rift among the world’s biggest automakers — the very industrial giants that the Trump administration maintains it was trying to help with regulatory relief.

The Trump administration has proposed a major weakening of federal auto emissions standards set during the Obama administration, prompting California to declare that it will go its own course and keep enforcing the earlier, stricter standards.

The automakers siding with the administration, led […]