California’s secretary of state and attorney general sent a cease-and-desist letter to Republican Party leaders on Monday following reports that GOP officials were encouraging voters to drop ballots into unofficial boxes that state officials contend are illegal.

“There is nothing more precious or fundamental in a real democracy than the vote,” California Attorney General Xavier Becerra (D) said in a statement Monday. “Anyone who tampers with the vote is tampering with free and fair elections. We will do all that’s necessary under law to protect Californians’ right to vote.”

The letter gives GOP chapters a Thursday deadline to provide the secretary of state’s office with the names, addresses and birth dates of people who have already dropped ballots into the unauthorized boxes, so that election officials can contact them and verify their ballots. Those ballots must also be returned to election officials by Thursday.

If the Republican Party chapters do not comply, state officials said they are “prepared to take action to enforce state law, should it become necessary.”

The metal boxes have popped up around Southern California in recent weeks, from churches to gun stores to gyms. On the front, an authoritative-looking sign beckons to voters: “Official ballot drop-off box.”

The California GOP has pushed voters to pop their mail-in ballots inside. Social media posts have advertised their locations, and one regional field director posted a photo to Twitter on Friday showing him holding a ballot in front of one of the boxes.

“Doing my part and voting early,” Jordan Tygh wrote in the now-deleted tweet, which was reviewed by The Washington Post before it was removed. “DM me for convenient locations to drop your ballot off at!”

But those containers, which were first reported by the Orange County Register and KCAL, are not county-authorized ballot drop-off sites. In fact, the unofficial boxes are against the law, state officials said Sunday.

“Operating unofficial ballot drop boxes — especially those misrepresented as official drop boxes — is not just misleading to voters, it’s a violation of state law,” California Secretary of State Alex Padilla, a Democrat, told The Post in an email. “My office is coordinating with local officials to address the multiple reports of unauthorized ballot drop boxes. Californians should only use official ballot drop boxes that have been deployed and secured by their county elections office."

Erecting or advertising unofficial ballot boxes could be a felony that carries a two-to-four-year prison sentence, according to the secretary of state’s office.

Official ballot return locations are listed on the secretary of state’s website. But Republican leaders are encouraging voters to bring their completed ballots to unlisted sites equipped with the unofficial green boxes, at locations including smog checks and gas stations.

Voting in 2020 is already different than any election ever before. Here are a few key voting terms to best understand how to make sure your vote counts. (The Washington Post)

The GOP said it was using a 2016 law, passed by Democrats, that the party argues legalized a practice called “ballot harvesting.”

“The Democrat anger is overblown when state law allows organizations, volunteers or campaign workers to collect completed ballots and drop them off at polling places or election offices,” California GOP spokesman Hector Barajas told The Post in an email on Monday. “If Democrats are so concerned with ballot harvesting, they are the ones who wrote the legislation, voted for it, and Governor Jerry Brown signed it into law. California Republicans would be happy to do away with ballot harvesting.”

In some states, ballot harvesting rules allow campaign volunteers to collect ballots door-to-door and return them to be counted on behalf of voters. That practice has been controversial, though legal in many states, over claims that it could lead to more ballots being lost or tampered with. Proponents of the practice argue that ballot harvesting can increase voter turnout and can be a useful solution for people with disabilities, obligations or other obstacles that may keep them from going to the polls themselves.

The California law allows people to hand their ballots over to any designated person, who then delivers the ballot. Under that law, California Democrats have held “ballot parties” where attendees fill out their mail-in ballots and leave them with volunteers who return the ballots en masse. But Republicans in the state often decry ballot harvesting, and the California GOP sued Gov. Gavin Newsom (D) this year over the practice.

Now, the party is using the same law to justify the unofficial ballot boxes, arguing that its boxes are akin to volunteers who collect ballots from voters. “This procedure has been in place since 2016 — not sure why people are all of a sudden surprised,” the California GOP tweeted.

The National Republican Congressional Committee also defended the unofficial ballot boxes, suggesting in a tweet that California Democrats were “only ok with ballot harvesting when it’s the Democrats ballot harvesting.”

But Padilla’s office said on Sunday that the boxes are not legal under the 2016 law, because that statute requires a voter to designate a “person” to return the ballot, and there is no person present at the unofficial drop-off boxes. Official drop-off boxes, meanwhile, must satisfy a long list of requirements to secure the boxes and ensure ballots cannot be tampered with. The GOP’s containers do not meet those requirements, Padilla said.

At least one chapter of the California Republican Party has said it is deploying its own ballot drop-off sites because of concerns over “security,” despite scant evidence that mail-in voting leads to fraud.

“CONSERVATIVE VOTER ALERT!” the Fresno GOP said in an introduction to its list of unofficial ballot return locations. “President Trump is very concerned about the lack of security with mail in ballots. Don’t take a chance that your vote will not be counted. Once your ballot arrives in the mail, mark your ballot completely and then walk it in, as soon as possible, to one of the secure locations listed below. Make sure your vote counts!”

The Fresno GOP deleted the list of ballot box locations on Monday, but an archived version was captured on the Internet Archive’s Wayback Machine.

Colorado, Oregon, Washington, Hawaii and Utah already send every voter a mail-in ballot each election, and many states have followed suit and widely expanded their absentee ballot options during the coronavirus pandemic. The shift, meant to limit the spread of the novel coronavirus at polling sites, could complicate the general election.

Fears of outright fraud from mail-in voting are based on shaky evidence. Three states with universal mail-in voting found that far less than 1 percent of the ballots cast in 2016 and 2018 were flagged as possibly fraudulent.

But mail-in voters can encounter some rare problems. A small number of ballots are never sent or are mailed to the wrong address. And some mailed ballots are rejected because of errors or because the voter returned the ballot too late.

After local reports raised concerns about the GOP’s ballot boxes, state officials issued guidance on Sunday clarifying that unofficial ballot drop-off boxes are illegal. Tygh’s tweet was removed by Twitter late Sunday night for violating the site’s rules.

The secretary of state’s office said it had received multiple reports of unofficial ballot boxes throughout the state, and said it would be sending updated guidance to the state’s political parties advising them of potential criminal penalties related to unsanctioned boxes. A spokeswoman for Orange County District Attorney Todd Spitzer told the Register prosecutors there are also investigating reports of improper ballot boxes.

“Voters are in control of how to return their ballot, and they have multiple safe and secure options for doing so,” Padilla said. “Ballots can be returned by mail, to any in-person voting location, or to an official secure drop box. Never hand your ballot over to someone you don’t trust.”