Trump DOJ Sues After California Refuses to Disqualify Voters Based on Faulty Citizenship Database

In what one former election official called a significant "escalation" of President Donald Trump's interference in the midterm elections, his Department of Justice sued California on Thursday for not disqualifying over 20,000 mail ballots from voters it claims could be noncitizens.

The suit comes two days after acting Deputy US Attorney General Trent McCotter sent a letter demanding that, within 48 hours, state election officials set aside ballots from a list of voters it determined were ineligible to vote using federal databases administered by the Department of Homeland Security (DHS)—systems that have previously been shown to regularly spit out errors.

When other states, like Nevada, Texas, and Missouri, have used the DHS system to vet their voter rolls for noncitizens, investigations have found that it incorrectly flagged hundreds of US citizens as ineligible to vote.

California officials have said the list of names was provided to them on a thumb drive, which came with a password written on a sticky note. They did not consider this to be a secure device and refused to open it. The letter was sent more than a week after California began sending mail ballots to 23 million registered voters.

The state refused to set the ballots aside, saying that the administration had not provided credible evidence that the voters were not citizens and that eligible voters could be disenfranchised. In its complaint Thursday, the DOJ called on the court to stop the ballots from being tallied until the citizenship status of each voter could be independently verified. It also requested that the state not send a ballot to anyone who has not yet received one.

The DOJ's batch of roughly 20,000 supposedly ineligible voters is a significant reduction from the 190,000 that Homeland Security Secretary Markwayne Mullin alleged were registered in the state back in July. When California asked for the underlying data and methodology for that figure, DHS declined to provide it.

"What happened to those 170,000?" said California Attorney General Rob Bonta at a press conference on Thursday. "They just got those wrong."

This highlights the concerns states have expressed about using the DHS system to purge their voter rolls. In refusing the DOJ's request, state officials have noted that in Nevada, the system flagged 185 voters as possible noncitizens only for state officials to determine that every single one of them was a US citizen.

California Secretary of State Shirley Weber responded to the DOJ's lawsuit with a sharply worded letter, accusing it of “demanding unprecedented measures that threaten thousands of Californians' right to vote, based on unverifiable information or methodology that you still fail to explain or provide.”

Weber described it as an effort to block “thousands of Californians’ right to vote” weeks before an election and said, “The extraordinary measures you demand are contrary to both federal and state law.” Federal law prohibits states from systematically purging voter rolls within 90 days of an election.

“We are not impressed with the federal government’s letter. We are not impressed with its lawsuit," Bonta said. “This is what the federal government does. They lie, they advance misinformation, disinformation, they advance conspiracy theories. They try to sow distrust with those lies."

“Their timing is rife with and smacks of and reeks of desperation and bad faith, to do this during an election,” he said.

Stephen Richer, the former Republican Maricopa County recorder in Arizona, described the government's lawsuit as "a real escalation by the federal government."

"I've mostly said 'Calm, calm. It's going to be OK' with respect to federal involvement in election administration," he wrote on social media. "This lawsuit—in October, in the middle of early voting—that asks election officials to disqualify certain voters based on suspect databases, not conclusive evidence, which definitely could have been alleged before early voting began... This does represent an escalation."

The University of California, Los Angeles (UCLA) Voting Rights Project filed an emergency brief on Thursday seeking to stop the DOJ from using its list to withhold ballots.

"With voting already underway, eligible citizens should not have their ballots withheld based on a federal list they have never seen and have had no opportunity to challenge," said its director, Chad Dunn. "We are asking the court to intervene before voters suffer harm that cannot be corrected after Election Day."

Sen. Alex Padilla (D-Calif.) said in a statement that the Trump DOJ "is now actively trying to interfere in the 2026 elections and strong-arm California into purging names from our voter rolls and blocking mail ballots based purely on vague allegations less than three weeks before Election Day."

He added, "This lawsuit has no legal basis or evidence behind it and is nothing more than a blatant abuse of power designed to sow distrust in our elections and threaten Americans’ right to vote."