A federal judge in Washington ruled Friday that the Justice Department broke the law when it built a nationwide program to pull state voter rolls and cross-check them against an immigration database, dealing a setback to one of the administration's signature pre-midterm initiatives less than a month before Election Day.

U.S. District Judge Sparkle Sooknanan found that the DOJ's so-called list maintenance project exceeded the department's statutory authority, ruling that Congress left the job of deciding who is eligible to vote to the states, not federal prosecutors, according to Al Jazeera. "The challenged policy represents the federal government's attempt to decide who gets to vote," Sooknanan wrote in her opinion.

How the fight started

The case traces back to an April lawsuit from the nonpartisan watchdog group Common Cause and four individual voters, who accused the administration of assembling what they called a sprawling new voter surveillance and purging apparatus ahead of the Nov. 3 midterms. The DOJ had pressed states to turn over unredacted voter rolls so they could be run against the Systematic Alien Verification for Entitlements database, an immigration-status lookup tool, to flag registrants it suspected were noncitizens.

Eighteen mostly Republican-led states complied and handed over the data, The Hill reported. The department went further with the holdouts, suing 30 states and the District of Columbia over their refusal to share voter information, though 26 of those suits have since been dismissed. Sooknanan concluded the program risked purging legitimate voters rather than catching fraud, citing a 2006 Social Security Administration audit showing the database and similar federal systems can carry outdated citizenship records that misidentify naturalized citizens as noncitizens.

"The Trump administration has repeatedly taken extreme measures to interfere with how elections are run," said Ming Cheung, a senior staff attorney with the ACLU's Voting Rights Project.

The ruling bars the DOJ from continuing to use rolls that states already turned over as part of the nationwide effort, extending beyond the holdout states to those that cooperated, according to U.S. News & World Report. States remain free to police their own rolls independently, including through ordinary use of the federal database.

A Justice Department spokesperson said Friday the agency was reviewing the decision and did not say whether it would appeal. The ruling marks a second defeat this year for the administration's voter-data push: in June, Sooknanan blocked a separate, expanded use of the same system for roll checks, though the Supreme Court temporarily paused that order last month.

Practically, federal law already bars systematic voter-roll purges within 90 days of a federal election, a window that opened before Friday's ruling and will likely blunt its real-world impact heading into the Nov. 3 midterms regardless of any appeal. Voting-rights groups say the broader fight over state voter data is far from over.