The battle over auto emissions standards has split the industry.
General Motors has joined Fiat Chrysler and Toyota in saying on Monday that they are siding with the Trump administration in taking on California over fuel economy standards, according to the New York Times.
The other side includes Honda and Ford after reaching a deal to follow California’s stricter rules.
At the heart of the dispute is the Trump administration’s rollbacks of regulations designed to fight climate change.
California wants to go its own way, while the Trump administration wants to weaken the standards set during the Obama administration.
The argument presented by the automakers siding with Trump is that the federal government and not California has the authority in the matter, according to The Times.
Those automakers are represented by the group the Association of Global Automakers.
General Motors and Fiat Chrysler referred queries to Global Automakers. Toyota did not immediately respond to a request for comment by the Times.
The legal fight could make it to the Supreme Court as an issue of states' rights.