The U.S. Supreme Court on Monday left blocked a Trump administration plan to impose new restrictions on mail ballots ahead of the 2026 midterm elections, siding with Democratic state officials and voting-rights groups that said the changes could disrupt voting systems nationwide. The court’s unsigned, one-paragraph order preserves a Massachusetts federal court injunction against the U.S. Postal Service rule through Nov. 3. The justices did not decide whether the rule is ultimately lawful, but a majority concluded that the challengers were likely to prevail in their case. The rule would establish technical requirements for envelopes carrying ballots and require states to provide the federal government with lists of eligible voters. Challengers argued that election officials did not have enough time to implement those requirements before an election that was roughly 50 days away when the court acted. Justice Brett Kavanaugh, in a brief concurrence, said the Postal Service might have statutory authority to issue the rule but that applying it in the 2026 election would be arbitrary and unworkable because state and local officials lacked sufficient time to make the changes. Justices Clarence Thomas and Samuel Alito dissented. Alito wrote that the Postal Service has broad authority over mail regulation and argued that the rule should remain in effect while the case proceeds. The case will continue before U.S. District Judge Indira Talwani, who was appointed by President Barack Obama. The remaining proceedings will address whether the rule is legal for future elections. The challengers also argue that the regulation is unconstitutional because elections are primarily administered by states, subject to congressional oversight, rather than by the executive branch. President Donald Trump attacked the ruling in a social media post, claiming without evidence that it would make fraud by Democrats easier. He also criticized several justices he appointed, including Kavanaugh, Neil Gorsuch and Amy Coney Barrett, over rulings he opposed. Officials and organizations challenging the rule welcomed the decision. Massachusetts Attorney General Joy Campbell said states should not be forced to disrupt their mail-voting systems because of the president’s political agenda. Common Cause President and CEO Virginia Kase Solomón said the ruling protects voters who rely on mail ballots, including elderly, rural and disabled Americans. California Gov. Gavin Newsom, whose state led the lawsuit, described the decision as a victory for democracy and the rule of law. California and Colorado are among eight states that mail ballots to every registered voter. The Postal Service and the Justice Department, which represented the administration, had not responded to requests for comment late Monday.