The election is over, and no more ballots can be cast. But campaigns in tight congressional races across California are scrambling to make sure their supporters’ votes are counted.

Through the increasingly common process known as “ballot curing,” campaigns are contacting voters whose ballots were not counted because of a technicality and giving them a chance to correct their mistakes. That could mean asking them to correct their address or add their signature to an envelope they forgot to sign.

The stakes are especially high in California’s battleground districts, where voters could determine which party will control the House of Representatives next year.

Of the 12 congressional races nationwide where the Associated Press has not yet called a winner, six are in California. Republicans need only two wins to achieve a majority in Congress — and obtain the elusive trifecta of being in charge of the House, Senate and the presidency.

In several tight races across California, both parties are rallying volunteers to help them reach voters and fix any problems with their ballots. They are fanning out across Orange and Riverside counties where Republicans and Democrats are in a furious battle for key seats in the House.

“Every vote does count,” said Kim Alexander, president of the California Voter Foundation. “People say it all the time, but you can actually see it with ballot curing in these close contests.”

The process has taken on heightened importance as California has shifted to predominantly conducting elections by mail. This year, every registered voter was mailed a ballot. Voters could send their ballots back through the mail or drop them off in designated boxes or voting centers.

But for a ballot to count, it must adhere to several rules, and ballots can be challenged for a variety of reasons. Among them: the ballot is missing from the envelope, multiple ballots were returned in one envelope, or the voter listed the wrong address. The most common reason for rejecting a ballot, according to the California Voter Foundation, is that it was returned too late. Over 75,000 ballots in California’s March primary were rejected because they were not received on time. Ballots must be postmarked by election day and received within seven days after the election.

Another common issue is the signature on the ballot envelope does not match a voter’s signature on other forms of identification.

“Young voters and first-time voters are more likely to have problems when they vote by mail because they’re just not used to using the mail, period. And they don’t have signatures that are well formed,” Alexander said. “The idea that somebody would have their ballot rejected when they’re voting for the first time is also very disheartening. We want people to have a positive first-time voting experience.”

According to state law, election officials must notify voters if there are issues with their ballots by reaching out via calls, texts or emails. Voters then have until Dec. 1 to fix their ballots and make sure they’re counted. As of Tuesday, California had roughly 161,000 ballots remaining to be cured before they are rejected.

In the March primary, a total of 108,982 vote-by-mail ballots were rejected, according to the California Voter Foundation — or 1.56% of those cast.

“It’s honestly really heartbreaking when you see these piles of ballots in elections offices,” Alexander said.

Election workers sort ballots at the Orange County Registrar of Voters in Santa Ana.

(Allen J. Schaben / Los Angeles Times)

In addition to election officials reaching out to affected voters, political parties have also gathered armies of volunteers to reach out to voters — especially those who are likely supporters of their candidates and causes — for ballot curing.

Battleground California, an independent expenditure campaign focused on six competitive congressional races has coordinated with community groups across Southern California to try to elect Democrats. Despite projections that Republicans may win a House majority, Michael Gomez Daly said each Democratic victory matters.

“When we walk into 2026, it’d be much easier to defend these seats versus having to flip them. And that’ll give Democrats nationally just a little bit of an extra advantage from a starting point,” said Gomez Daly, a senior political strategist with California Donor Table and chair of Battleground California.

Gomez Daly reviewed data from the Riverside County registrar that showed voters between the ages of 18 and 24 had a disproportionate number of ballots rejected due to mismatched signatures. Those ballots could impact the 41st Congressional District, where Republican incumbent Rep. Ken Calvert holds a lead over Democratic challenger Will Rollins.

“It just so happens that the younger electorate are predominantly voters of color,” Gomez Daly said.

In the Riverside County district that Democrats are trying to flip, he said, “the voting electorate between 18 to 24 that’s being rejected are predominantly Latino.”

In Orange County’s 45th Congressional District, where the contentious battle between GOP Rep. Michelle Steel and Democratic challenger Derek Tran may come down to a few thousand votes, volunteers are gearing up to work nearly 40 hours to cure ballots until the Dec. 1 deadline.

They plan to knock on doors and reach voters because “every vote should be counted,” said Hairo Cortes, the executive director of Chispa, an advocacy group that predominantly works with young Latinos in Orange County.

“If this is what puts Derek Tran over the line, we have a responsibility — all of us, collectively — to do everything within our means to ensure that there is new leadership in that district,” Cortes said.

Political campaigns are seizing on the opportunity to fundraise, sending pleas to their supporters for money to help the ballot curing process.

“President Trump has won the White House, but the election is NOT over,” read a fundraising email from Republican Rep. Elise Stefanik, chair of the House GOP Conference. “We need to be certain that Republicans are present for every instance of ballot counting and curing to ensure a clean and honest process.”

She asked recipients to contribute money “as we fight to count every last LEGAL vote.”