A federal judge in Boston has issued a preliminary injunction blocking core provisions of President Donald Trump’s March executive order that sought to create a national list of eligible voters and direct the United States Postal Service to deliver mail-in ballots only to individuals on that list. The ruling, handed down Thursday by District Judge Indira Talwani, prevents the administration from enforcing the measures ahead of the November 2026 midterm elections, finding that the Constitution reserves the power to determine voter eligibility to the states alone.

The coalition of 23 states and the District of Columbia that brought the suit argued that the executive order represented an unconstitutional intrusion into state-administered elections. In her opinion, Judge Talwani wrote that neither the executive branch nor Congress may interfere with the states’ authority over voter rolls, and that the president ‘plays no direct role in the process’ of appointing electors. The White House, through a spokesperson, said the order lawfully protects election integrity and expressed confidence that it would ultimately prevail on appeal.

The ruling directly undercuts a proposed Postal Service regulation, published earlier this month, that would require states to transmit lists of approved mail-in and absentee voters—along with unique barcode identifiers—to the federal agency. At a Senate hearing on Wednesday, Postmaster General David Steiner confirmed that under the proposal, the USPS would not deliver ballots in any state that declined to provide such a manifest. Democratic senators described the mechanism as coercive, while Steiner maintained it would simply ensure that the ballots a state intends to send are those actually dispatched.

Thursday’s decision is the third in a week to halt elements of the administration’s election agenda. A separate federal judge on Wednesday permanently blocked a provision requiring documentary proof of citizenship for voter registration, and another on Monday halted a voter-screening database that consolidated personal information from millions of Americans. The president has long argued, without evidence, that mail-in voting is susceptible to fraud, and has pressed Congress to pass the Safeguard American Voter Eligibility (SAVE) Act, which would impose uniform photo identification requirements and restrict mail-in voting. The Postal Service’s proposed rule remains open for public comment until 2 July, and the Justice Department is expected to appeal Thursday’s injunction to the First Circuit.