Discussion of the idea exploded Wednesday on Twitter, where tweets with the hashtag #calexit rolled in at hundreds per minute all day. Many — often paired with the hashtag #notmypresident, in reference to Donald Trump's election — backed the movement, but a significant proportion also adopted the hashtag to ridicule it.
YesCalifornia, a political action committee formed in August 2015, is working for a referendum on the 2019 state ballot that would start the long path to legal secession.
"In our view, the United States of America represents so many things that conflict with Californian values, and our continued statehood means California will continue subsidizing the other states to our own detriment, and to the detriment of our children," the group says in a 33-page "CalExit Blue Book."
The movement "is about California taking its place in the world, standing as an equal among nations," it says. "We believe in two fundamental truths: (1) California exerts a positive influence on the rest of the world, and (2) California could do more good as an independent country than it is able to do as a just a U.S. state."
California is the country's most populous state, making up 11.6 percent of the U.S. population, according to mid-year figures from the U.S. Census. If it became a separate nation, it would be the 35th-biggest country on Earth, according toU.N. data.
But getting there will be extraordinarily hard. An 1869 Supreme Court ruling called Texas v. White suggests that there are only two ways for a state to leave the union: "through revolution or through consent of the States."
YesCalifornia rejects revolution. So independence could come only after a series of increasingly unlikely events — assuming the referendum gets on the 2019 ballot at all, something California voters will first have to decide in 2018.
All peaceful avenues to independence involve amending the U.S. Constitution — meaning the legislatures of two-thirds of the states would have to consent to letting the country's biggest state and its most powerful economic engine walk away.
Still, some pretty heavy hitters, especially in the tech-rich northern half of the state, are on board.
Tuesday night, as Trump's victory became increasingly apparent, a number of Northern California tech entrepreneurs joined in an extraordinary Twitter thread started by Shervin Pishevar, co-founder of the futuristic transportation venture Hyperloop One, who promised to fund "a legitimate campaign for California to become its own nation."
Big bucks executives who joined the thread in support included angel investor Dave Morin, a former Facebook executive and chief executive of the social network Path; and Anand Sharma, founder of the health tracking iPhone app Gyroscope.
Pishevar told CNBC on Wednesday that he's not joking.
"It's the most patriotic thing I can do," he said. "The country is at serious crossroads. ... As the sixth-largest economy in the world, the economic engine of the nation and provider of a large percentage of the federal budget, California carries a lot of weight."