It appears that California has defeated Trump on car tailpipe emissions. If so, then this is a very important victory for rational Americans because California has "aggressive limits on vehicle emissions"; and this matters because car manufactures will not make special cars for California and regular cars for the rest of the US. Its market is too huge (indeed, the biggest in the country), and so they are forced to make all of their vehicles comply with California's high standards.

From the San Francisco Chronicle.

The Trump administration may be quietly conceding defeat to California on car tailpipe emissions, the biggest battleground in the state’s showdown with President Trump over climate change.

Environmental Protection Agency chief Scott Pruitt backed away last month from his threats to challenge California’s unique legal authority, known as a waiver, to set aggressive limits on vehicle emissions, including greenhouse gases.

Although Pruitt left the door open to a future challenge, experts said he is running out of time to stop California from dictating national pollution standards on cars, the nation’s primary source of greenhouse gas emissions.

But this victory also has a deeper significance. California has a reputation for being the first state to arrive at the US's future.

And that future is looking less and less like the great past Trump and his voters are trying return to. California is the first US state "to ban single-use plastic shopping bags" statewide. It is the first state "to require LGBT history in schools." It's the first state to require students in high schools to learn that pussy grabbing is a sexual assault and what precisely consent means: yes means yes, and no means no.

It's also one of the few minority-majority states in the US, and so it represents exactly the kind of American society that many of Trump's white voters deeply fear. But if you can't stop California, it's really hard to stop the Californization of the US.