It’s not really a state rights thing though: my state is not allowed to do something like that on its own

This is a federal thing that there’s a specific exception for California and the rest of us can only follow them or stick to federal standards

Articles keep linking this back to the clean air act but I don’t remember reading where the exception is. If it’s in the clean air act, I don’t see how Trump can change that: it has to be Congress. If it’s an EPA regulation or executive exception, that’s another story, but hopefully would at least be time consuming