The U.S. Supreme Court on Monday blocked the Trump administration’s attempt to impose new restrictions on mail ballots ahead of the November midterm elections, allowing states to continue using established procedures for mail-in voting. The decision came as election officials had already begun mailing ballots in several states, including North Carolina and Wisconsin.

In an unsigned, brief order, the court rejected the administration’s emergency request to enforce new U.S. Postal Service rules requiring states to redesign ballot envelopes, submit voter lists with barcodes to a federal portal, and obtain postal sign-off before mailing ballots. These rules were introduced last month at President Donald Trump’s direction amid his persistent concerns about election integrity and mail-in voting, despite a lack of evidence of widespread fraud related to mail ballots.

The court’s majority found the administration “unlikely to succeed on the merits” of its challenge to a lower court injunction blocking the rules, effectively maintaining that injunction through the midterms. Two conservative justices, Clarence Thomas and Samuel Alito, dissented from the decision. Alito argued the Postal Service has broad authority to regulate mail and could enforce the new guidelines, while Justice Brett Kavanaugh agreed the restrictions should be blocked for the current elections but suggested he might support them in the future.

State and local officials had warned that the sudden imposition of the new requirements would cause significant logistical problems so close to the election, given that millions of ballots had already been printed or sent out under existing systems. Some states rely heavily on mail voting, with nearly a third of votes in 2024 expected to be cast this way, leading officials to describe the Postal Service rules as impractical and potentially unconstitutional.

The Postal Service itself acknowledged difficulties in implementing the new rules, including a portal necessary for the voter information submission that was not yet operational by early September. An anonymous whistleblower within the agency had reported challenges in rolling out the changes promptly.

The ruling represents another judicial setback for the Trump administration on key election-related issues ahead of the midterms, which will determine control of Congress during the president’s remaining two years in office. The Supreme Court has also recently blocked other voting disputes, such as a Republican-friendly congressional map in Missouri, and could soon weigh in on additional voting-related controversies, including the use of immigration databases for voter eligibility screening.