The struggle for standards for auto emissions has divided the industry.
General Motors has joined Fiat Chrysler and Toyota said on Monday that they support the Trump administration in taking on California above fuel economy standards, according to the New York Times.
The other side includes Honda and Ford after reaching an agreement to follow California's stricter rules.
At the heart of the dispute lies the Trump administration's return of regulations designed to combat climate change.
California wants to go its own way, while the Trump administration wants to weaken the standards set during the Obama administration.
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The argument that automakers support Trump is that the federal government, not California, has authority over the case, according to The Times.
These automakers are represented by the Association of Global Automakers.
General Motors and Fiat Chrysler referred questions to Global Automakers. Toyota did not immediately respond to a request for comment from the Times.
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The legal battle may do so for the Supreme Court as a matter of state rights.