EPA vs. California's new electric vehicle mandate

The letter Monday says there are "serious questions" about the plan's legality and that it may require a waiver from EPA, per Reuters' report on it.

Why it matters: California is the nation's largest auto market. Newsom's plan last week is the most aggressive U.S. move to curb carbon emissions from transportation and push electric vehicles.

• Wheeler's letter underscores the stakes of the ongoing litigation between EPA and California over cars, as well as the outcome of the election, and even the Supreme Court makeup.
• Last year the Trump administration revoked the state's special authority under the Clean Air Act to set its own tailpipe emissions rules that a number of other states may adopt.

Yes, but: The fight over California's plan is in its early stages. Newsom's executive order last week is only a first step. State regulators' completion of final rules to actually implement it is likely years away.

The intrigue: It's a legal fight, but also a PR battle, with Wheeler's letter taking aim at California's recent rolling blackouts.

• The states' power woes raise the question of "how you expect to run an electric car fleet that will come with significant increases in electricity demand, when you can’t even keep the lights on today," it states.
• Newsom spokesman Jesse Melgar, in a statement to several outlets, said the Trump administration is trying to "drive this country off a climate cliff."
• “We aren’t going to back down from protecting our kids’ health and the air they breathe," he said.