A federal judge in Washington has struck down the Trump administration’s overhaul of a government database that pooled sensitive personal information on millions of Americans to verify voter eligibility. US District Judge Sparkle L. Sooknanan ruled on Monday that the modified Systematic Alien Verification for Entitlements (SAVE) system violated the Social Security Act, the Privacy Act and the Administrative Procedure Act, and ordered its use halted. The decision removes a central instrument from the White House’s election integrity agenda just months before November’s midterm elections, in which Republicans are defending narrow majorities in both chambers of Congress.

According to the court, the administration “knowingly trampled on the privacy rights of American citizens” by combining citizenship data from the Department of Homeland Security with Social Security records, creating what the judge described as a searchable national registry. The ruling noted that federal agencies were aware the citizenship information was unreliable and could incorrectly flag naturalised US citizens as non-citizens. The Trump administration, through the Department of Homeland Security, had defended the database as a lawful modernisation of a system in use since 1986, arguing that Congress had directed agencies to break down information silos. Justice Department lawyers told the court that only a “tiny number” of voters might be affected by inaccurate data, a contention the judge rejected, writing that even one disenfranchised voter was too many.

The practical consequences are already visible. Evidence cited in the case showed that several states had used the expanded SAVE system to cross-check voter registration lists, resulting in eligible voters being wrongly removed from the rolls. Voting rights groups and privacy advocates who brought the suit argued that the database effectively created a centralised federal voter file of the kind Congress had expressly prohibited. The ruling also complicates a parallel administration effort to condition hundreds of millions of dollars in homeland security grants on states adopting election reforms, including the use of the SAVE database to purge suspected non-citizen voters. Legal analysts in Washington note that those grant conditions are likely to face similar judicial scrutiny.

The SAVE expansion originated from an executive order President Trump signed last year that sought to impose a proof-of-citizenship requirement for voter registration. Other provisions of that order have already been blocked by courts. The administration is expected to appeal Monday’s ruling, and the case may ultimately reach the Supreme Court. The dispute reflects a deeper constitutional tension: while the US Constitution assigns election administration to the states, the White House has pressed for greater federal oversight, citing unsubstantiated claims of widespread voting by non-citizens. The Department of Homeland Security criticised the decision as an example of the “Left” fighting to prevent problems it insists do not exist, and signalled it would resist the ruling.