Trump gets personal in auto emissions fight

A move by at least 4 big automakers to cut a separate deal with California on nationwide emissions standards clearly has President Trump's attention on Twitter.

"Henry Ford would be very disappointed if he saw his modern-day descendants wanting to build a much more expensive car, that is far less safe and doesn't work as well, because execs don't want to fight California regulators."

Why it matters: The tweets represent an escalation in the battle over one of the most far-reaching Obama-era climate efforts. They come as major automakers are weighing whether to join Ford, Honda, VW and BMW in the pact with California.

• The pact effectively rebuffs his plan to freeze Obama-era emissions and mileage rules, rather than allowing them to get more stringent through the mid-2020s.

The big question: Will Trump's public criticism give other automakers pause about joining the deal?

• The industry is an an awkward spot. It felt former President Obama's mandates were infeasible, but argues Trump's plan to freeze them outright goes too far.
• Mercedes-Benz and one other major company are reportedly interested in joining the agreement.

The intrigue: The Wall Street Journal reports that some foreign-based carmakers fear that explicitly breaking with Trump by joining the deal could "embolden" the president to carry out tariff threats.

• GM, meanwhile, "doesn't think the California proposal gives enough credit for sales of fully electric vehicles," per WSJ.

The big picture: Reuters points out that Trump's claims are highly questionable, highlighting that "there is no evidence that existing fuel economy rules would degrade vehicle performance."

Go deeper: Big Auto's rupture with Trump