California election officials have until noon Thursday to comply with an extraordinary demand from the Justice Department: open a password-protected thumb drive containing a secret list of people the federal government believes are noncitizens who received mail-in ballots for the Nov. 3 midterms, then set those ballots aside. So far, the state is refusing to even plug it in.

The order came in an Oct. 13 letter from acting Deputy Attorney General R. Trent McCotter to California Secretary of State Shirley Weber and Los Angeles County Registrar-Recorder Dean Logan, according to NBC News and CBS News. McCotter asked officials to review the names on the drive within 48 hours, "segregate — not cancel" the mail ballots of anyone whose citizenship can't be confirmed, and withhold ballots from listed people who haven't been sent one yet.

A Drive Nobody Will Open

Logan's office says it won't even insert the device. "We do not consider the device a secure medium," he said, adding that removing any voter from the rolls has to rest on verifiable information, not an unconfirmed data match. Weber went further, saying her office never actually received a list of names despite DOJ's letter referencing one, and accused the department of trying to unlawfully access protected voter data. Both officials confirm they received the letter. Neither has opened the drive.

The timing is tight by design. California began mailing ballots to every one of its registered voters on Oct. 5, and federal law generally bars systematic voter-roll purges within 90 days of a federal election — changes are supposed to be limited to individualized cases, like a Social Security Administration death notice, a former DOJ voting-rights official told NBC News. With Election Day 19 days out, there's almost no window left for California to act even if it wanted to.

This isn't DOJ's first swing at the issue this year. In July, Assistant Attorney General Harmeet Dhillon sent letters to all 50 states warning that officials "could be subject to criminal liability" for knowingly keeping noncitizens on voter rolls, and the department's civil rights division has filed roughly three dozen lawsuits nationwide seeking unredacted statewide voter files — winning none of them so far, per CBS News' review of the cases. Homeland Security Secretary Markwayne Mullin separately told Weber's office in July that a preliminary federal data review had flagged a large number of potential noncitizen registrations in the state, a claim her office has called unreliable and based on flawed commercial data matching.

Voting researchers and election officials from both parties have repeatedly found confirmed noncitizen voting to be exceedingly rare nationwide. Even so, the Trump administration has brought more than 100 criminal cases alleging voter fraud-related crimes since taking office, according to NBC News.

California isn't the only state feeling federal pressure three weeks before voters decide control of Congress. Election officials in Georgia, Connecticut, Nevada and Washington state say they've received similar federal subpoenas for voter records in recent weeks.

"WHAT WE HAVE SEEN IS SOME GROUNDWORK LAID OUT FOR POSTELECTION CHALLENGES," Washington elections director Stuart Holmes told NBC News.

What happens when Thursday's deadline passes with the drive still unopened is an open question. Neither NBC nor CBS reported what specific legal action DOJ is prepared to take, and a department spokesperson said only that officials want ballots "sequestered," not the voter rolls altered. For now, the dispute is less about any proven noncitizen vote in California than about who gets to touch the state's ballots — and whose numbers to trust — with the House and Senate majorities still up for grabs.