Activists who want California to leave the United States have filed papers to set in motion a process they hope would end with Golden State voters deciding whether to secede in 2021.

This is the second attempt at a “Calexit,” as supporters call their effort. The first measure died last year during the signature-gathering process.

Secession supporters, who say the Trump administration is specifically targeting their state, will begin gathering signatures to qualify a ballot question in 2020. That initiative would ask voters whether to hold a secession vote — and, if it passes, that vote would take place May 4, 2021.

The secession vote would instruct the state legislature to formally declare California’s independence from the United States.

Backers of the measure marched from the state Capitol in Sacramento to Attorney General Xavier Becerra’s (D) office on Wednesday, waving signs that read “It’s Time For A Divorce” and “Irreconcilable Differences.” At Becerra’s office, they formally filed the papers necessary to begin gathering signatures for the 2020 ballot.

Supporters of secession are the latest in a long line of activists who have pushed for California to leave the United States. Since 1859, a decade after California joined the union, more than 200 different groups have tried to force either secession or partition, splitting the state into several smaller states, according to the Los Angeles Times.

But in an age of Russian interference in American politics, the secession movement has sparked concerns that outsiders might try to influence the debate. A Russian-linked Twitter bot that tweeted in support of leaving the U.S. was one of those shut down by Twitter last November, according to the San Diego Union-Tribune, reporting testimony the company provided to Congress.

The sponsor of the referendum, Louis Marinelli, dropped last year’s effort after admitting he was living in Russia at the time. Marinelli says he has moved back to the United States, and he was present when supporters filed paperwork with Becerra’s office this week.