California Governor Gavin Newsom on Saturday warned federal courts to be ready for potential attempts by President Donald Trump‘s administration to seize ballots during the upcoming midterm elections.

Newsom, a Democrat, sent the warning letter to federal judges as the state’s legal fight with the administration, which demanded records from California as part of a criminal investigation into noncitizen voting. On Friday, a US appeals court rejected the administration’s bid, potentially setting up a showdown at the US Supreme Court.

Separately, a federal judge ordered the Justice Department to stop threatening to prosecute state and local election officials in California who refuse to comply with the administration’s election-related demands.

“Given the United States Department of Justice’s persistence in advancing this baseless theory of criminal liability, I have grave concerns federal agents will seek search warrants to seize ballots and ballot materials before the election results are certified,” Newsom wrote.

The only reason to use search warrants would be to interfere in the state’s “lawful counting of ballots and certifying the results of the election,” Newsom wrote to the federal judges.

The US Constitution assigns the administration of elections to the states, but the Trump administration has alleged that more than 20,000 noncitizens are registered to vote in California, though the state and many experts have questioned the validity of the list. The Justice Department has not said how many of the people on its list have actually submitted ballots.

California has said the Justice Department’s assertions relied ⁠on “suspect data” ​and that complying with its demands would risk disenfranchising eligible voters.

–

(Reporting by Max A. Cherney in San Francisco; Editing by Sergio Non and David Gregorio)