A federal judge on Wednesday restricted the Department of Homeland Security from election-related investigations in nine states, finding that error-prone government lists could sweep U.S. citizens into the effort.
Heading into the midterm elections, DHS has launched a wide-ranging effort to track down noncitizens it suspects of voting or registering to vote.
U.S. District Judge Araceli Martínez-Olguín barred DHS from relying solely on records generated through its voter-matching program for field operations involving people it knows, suspects or should reasonably suspect are U.S. citizens.
The judge put her order on hold until 5 p.m. Friday, giving President Donald Trump’s administration time to appeal. DHS and Justice Department officials did not immediately comment.
Her ruling applies to the nine states where DHS has focused its operations on voting issues: California, Connecticut, Georgia, Missouri, Nevada, New York, Pennsylvania, Washington and Wisconsin.
DHS built target lists from records on tens of millions of voters from official state voter rolls, commercial voter files and lists of 48.2 million voters that the judge deemed to have “questionable provenance.” The agency used artificial intelligence tools to enhance that data to find suspected noncitizens, who are ineligible to vote in federal elections.
During the agency’s surge of investigations, DHS personnel were ordered to complete at least 40 reviews and had no more than 12 minutes to clear someone from the target list using commercial databases, the judge wrote. She found a high likelihood of error, in part because no federal database definitively captures the citizenship status of U.S. residents.
The California Nurses Association and other groups sued over the initiative. The judge found that those organizations were likely to succeed on their claim that the administration’s initiative violates the Voting Rights Act’s prohibition on intimidating people who assist or mobilize voters.
“The fear is objectively reasonable, and compounded by [DHS’s] use of data that is widely known to inadvertently include U.S. citizens, leaves citizens afraid that their name will be wrongly included in the hundreds of thousands identified for investigation,” wrote Martínez-Olguín, who was appointed to the bench by President Joe Biden.
The decision is part of a broader legal fight over noncitizen voting that is intensifying in the weeks before midterm elections that will decide control of Congress.
Last week, the Justice Department sued California election officials, alleging it had identified more than 20,000 noncitizens on their voter rolls and seeking an order that would prevent those voters’ ballots from being counted unless they proved their citizenship. Election officials called the lawsuit a political stunt and said a preliminary review of the data found the federal government’s allegations riddled with errors.
And this week, the Justice Department announced charges against 28 Californians, accusing them of registering to vote or voting before they became naturalized citizens. Justice Department officials have recently touted similar charges and arrests in other states on social media and television appearances.
The judge’s order Wednesday stemmed from a lawsuit brought by the state nurses association, National Nurses United, the Voto Latino Foundation, Santa Clara County and the city and county of San Francisco.
“Today, the courts affirmed a vital principle of our democracy,” said Beau Tremitiere, an attorney with Protect Democracy who represents the groups. “Voting is a fundamental right that citizens - whether born here or naturalized - should be able to exercise without armed government agents harassing them.”
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This article originally appeared on Washington Post at https://washingtonpost.com/politics/2026/10/22/judge-blocks-dhs-investigations-noncitizen-voting-citing-flawed-data/