The Trump administration has escalated its fight with California over mail ballots, warning local election officials in a letter that processing or tabulating ballots from suspected noncitizen voters could expose them to criminal investigation and prosecution.

In the letter, first obtained by the Associated Press, acting Deputy Attorney General Trent McCotter wrote that knowingly tabulating such ballots risks making officials 'aiders and abettors to a federal crime.' It was addressed to the Los Angeles County counsel's office and copied to California Secretary of State Shirley Weber and Los Angeles County Registrar Dean Logan, effectively putting officials statewide on notice.

The letter arrived a day after the administration sued California to block the counting of mail ballots from people federally identified as 'likely' noncitizens. The suit followed the state missing a 48-hour deadline to review a password-protected thumb drive containing 20,000 names; Weber's office says the administration has provided no evidence for its claim.

President Trump posted on Truth Social late Friday that those responsible 'will all go to jail for a long period of time.' UCLA law professor Rick Hasen said the letter 'ups the ante by threatening election officials with potential criminal prosecution.' For context, the Justice Department has charged roughly 50 people over alleged noncitizen voting, out of more than 227 million registered voters in the 2024 election; California alone has more than 23 million registered voters.