Suit claims California tosses thousands of ballots every election

California wrongly disqualifies tens of thousands of mailed-in ballots in each election because officials decide the voter’s signature on the ballot envelope doesn’t match earlier submissions, the American Civil Liberties Union said in a lawsuit Thursday.

The decisions, the suit said, are made by untrained staff without prior notice to the voter.

“People should not be denied their right to vote because a government official doesn’t like their penmanship,” ACLU attorney Michael Risher said in a statement accompanying the suit, which was filed in the state Court of Appeal in San Francisco.

More than half of California’s voters cast their ballots by mail. The ACLU is challenging a law that allows county election officials to refuse to count a ballot if they decide the signature on the envelope is different from the voter’s signature on the registration form or other documents on file. The law does not require county registrars to notify voters or give them a chance to verify their identity.

A 29-county study after the 2016 election estimated that as many as 45,000 ballots were disqualified statewide because of alleged signature mismatches, the ACLU said. It said rejection rates were nearly 40 percent higher for Asian Americans than for the rest of the population, and nearly twice as high for Latinos.

The suit was filed on behalf of a Sonoma County resident, Peter La Follette, 25, who learned after the November election that the county had refused to count his mailed-in ballot. La Follette contacted the registrar’s office and was told last month that his signature on the ballot envelope differed “significantly” from the signature on file with the office — a discrepancy he could have fixed had he been notified before the election, the suit said.

Although automatic signature-verification technology is available, the ACLU said, most counties rely on personal inspection by staff who have no training in handwriting analysis.

The suit seeks a court order requiring elections offices to notify voters of any concerns about their signatures and give them a chance to respond before discarding their votes.

Asked about the lawsuit, Sam Mahood, spokesman for Secretary of State Alex Padilla, the state’s top elections official and a defendant in the case, said California “is leading the nation in adopting measures to empower voters” and has one of the nation’s lowest rates of rejecting mailed-in ballots. He did not comment on the ACLU’s complaints about the signature-matching process.

Bob Egelko is a San Francisco Chronicle staff writer. Email: begelko@sfchronicle.com Twitter: @egelko