California wants to set its own emission rules, possibly going further than the preexisting standards that the (current) EPA claims may be economically untenable. But the board’s assertion that it cannot work with the Trump administration, or vice versa, effectively encourages the split-market outcome and nullifies any claims that it is supported by most OEMs.
Here’s what actually happened: Automakers lobbied aggressively for the rollback and were greeted by an administration that was highly interested in deregulation in 2017. A proposal was developed and California, keen to maintain its own, more-ambitious emission standards, fired back by saying it wouldn’t agree to the suggested rollback and would happily go to court. Both sides have been at odds ever since, with neither willing to make any legitimate concessions.