Interest in pushing for California's secession from the United States has increased since Donald Trump won the presidency, with the effort becoming known as "Calexit."
The "Yes California" campaign is backing an independence referendum in support of a constitutional exit of the state from the United States.
Trump won just 33.2 percent of votes in California, compared to Hillary Clinton's 61.5 percent.
The day after the election, Yes California supporters held a daylong "meet and greet" in front of the state Capitol building in Sacramento. The event was planned well before Election Day.
"As the sixth largest economy in the world, California is more economically powerful than France and has a population larger than Poland. Point-by-point, California compares and competes with countries, not just the 49 other states," the campaign's website reads.
The "Calexit" name stems from the successful "Brexit" campaign for Britain to leave the European Union.
Interest in the effort has soared since Tuesday, campaign spokesman Marcus Ruiz Evans told KTLA sister station KTXL in Sacramento.
"It's game-changing," Evans said.
In 24 hours, the group's membership grew from 3,000 to nearly 5,000, he said Wednesday evening.
"The relationship between California and the federal system just isn't working," Evans told the Los Angeles Times.
While the Yes California campaign has been considered a fringe movement in the past, it began trending on social media Tuesday night, attracting mainstream notice and interest from California progressives dismayed by Trump's impending win.
The leaders of California's Assembly and Senate, both Democrats, issued a joint statement Wednesday morning that was widely shared.
The statement from Senate President pro Tempore Kevin de León and Assembly Speaker Anthony Rendon began:
Today, we woke up feeling like strangers in a foreign land, because yesterday Americans expressed their views on a pluralistic and democratic society that are clearly inconsistent with the values of the people of California.
We have never been more proud to be Californians.
By a margin in the millions, Californians overwhelmingly rejected politics fueled by resentment, bigotry, and misogyny.
The largest state of the union and the strongest driver of our nation’s economy has shown it has its surest conscience as well.
The legislative leaders, of course, have not expressed support for secession.
"California was not a part of this nation when its history began, but we are clearly now the keeper of its future," the statement concluded.
Meanwhile, the implausibility of actual secession apparently hasn't dissuaded those frightened by the prospect of Trump running the federal executive branch.
California's exit from the union would require approval of two-thirds of legislators in both the U.S. House of Representative and the Senate, as well as support from at least 38 state legislatures, according to the New York Times.
There have been at least 200 failed proposals for the state to secede since it joined the U.S. in 1850, the newspaper reported.
The rising interest in Calexit comes as protests have erupted across the U.S.
On Wednesday night, thousands gathered in at least a dozen major U.S. cities. In Los Angeles, protesters chanted "¡Si se puede!" in the streets of downtown.
The refrain "not my president" rang out from angry crowds in L.A., San Francisco and elsewhere.
Police estimated thousands of people stood outside New York City's Trump Tower protesting the president-elect's positions on immigration and law enforcement.
"I came out here to let go of a lot of fear that was sparked as soon as I saw the results," protester Nick Powers said.
Calexit protesters in Sacramento, meanwhile, held blue signs that said "California Is a Nation Not a State."
The group's protesters joined with thousands of others in Sacramento who were focused on protesting the Trump presidency.
Protests continued Thursday, with students walking out at many schools in California and elsewhere.