Jenny Farrell, the executive director of the League of Women Voters of California, told me that taken together, the developments are part of “a growing pattern of actions both in California and nationally that risk undermining public confidence in our elections.”

Bianco’s office seized roughly 1,000 boxes – about 650,000 ballots – from the Riverside County Registrar of Voters in late February.

His reasoning: A citizens group called the Riverside Election Integrity Team, said their audit of ballot intake forms found just 611,426 ballots — 45,896 short of the county’s final count of 657,322 votes. The local group claimed officials overstated the tally in an election where California voters overwhelmingly approved Proposition 50, a Democratic redistricting plan.

“The investigation is going to determine what the discrepancy is,” Bianco said at a news conference Friday. “Is it human error? Is it machine error?”

But in a presentation to the Riverside County Board of Supervisors in February, Registrar of Voters Art Tinoco said the ballot intake forms, filled out by hand by volunteers at voting locations, were not a reliable source to compare to the final vote count — which takes place after a machine scan of ballots at county offices.

“These are completed in the field by election officers during long work days — let’s keep that in mind, folks get tired,” Tinoco said. “It’s very possible that the staff may not have recorded the numbers accurately on these daily mail intake forms.”

A hand places a pieces of paper in the ballot box.A voter casts a mail-in ballot at a polling site at Fresno City College in Fresno on Nov. 5, 2024. California’s vote-by-mail system is facing renewed legal and political challenges. (Larry Valenzuela/CalMatters/CatchLight Local)

County supervisors vowed to look further into the ballot intake forms. But Bianco’s move to seize the ballots was “unprecedented,” said Matt Barreto, faculty director of the UCLA Voting Rights Project.

“The single most important thing is having transparency and trust in the counting of the ballots,” Barreto said. “In no election should law enforcement officials be seizing ballots, removing them from the county and doing a private and separate count.”

After all, Bianco is a leading candidate for governor in the state’s June 2 primary. Any move to align himself with Trump’s crusade against mail voting could help Bianco overtake his Republican rival in the race, commentator Steve Hilton.

“He’s certainly pursuing it only for publicity, not for election integrity,” Barreto said — a charge Bianco denied at his press conference.

In a lawsuit filed Monday, California Attorney Rob Bonta asked the state’s 4th District Court of Appeal to freeze Bianco’s investigation and halt a new count of ballots.

“The Sheriff has not identified any particular crime that may have been committed by anyone — a necessary predicate to obtain a criminal search warrant,” Bonta’s office said in a statement. “By all appearances, this investigation is little more than a fishing expedition meant to sow distrust and undermine public confidence in our elections.”

But a three-judge panel on the appeals court denied Bonta’s petition on Tuesday and instructed the attorney general to file his suit with a lower court instead.

No one appears more determined to discredit vote-by-mail than Trump, who this week said, “mail-in voting means mail-in cheating.”