Documents outlining the EPA's plan to roll back vehicle emission standards reference California by name 27 times.

The Environmental Protection Agency’s plan this week to relax rules aimed at cleaning up auto tailpipe emissions is the latest Trump administration move to undo incentives for automakers to go

That assessment followed a 2007 U.S. Supreme Court decision in its landmark Massachusetts v. EPA case that said the EPA has the authority under the Clean Air Act to regulate greenhouse gas emissions and required the agency to make a scientific finding on whether those emissions endanger public health.