The news came, like so much else these days, over Twitter. In a series of tweets Wednesday, President Trump said his administration will revoke California’s ability to set its own vehicle emission standards. The state’s leaders have promised resistance, and the fighting will likely take the form of a lengthy court battle. The result (especially if Trump wins a second term) could determine how emissions are regulated across the country.
That’s because for more than 50 years, California has led efforts in the US—and much of the world—to curb the damage that cars and other vehicles inflict on human and planetary health.