Supreme Court Blocks Trump USPS Mail Ballot Rules Ahead of 2026 Midterm Elections

Mail voting in the 2026 US midterm elections will proceed under existing state procedures after the Supreme Court on 14 September refused to reinstate new US Postal Service rules for federal ballot mail, dealing a setback to the Trump administration's plans to tighten standards before polling day.

In a brief order, the court denied the administration's request for a stay, finding that the government was unlikely to succeed on the merits of its challenge and that the balance of harms did not justify emergency intervention.

Justices Clarence Thomas and Samuel Alito dissented. Justice Brett Kavanaugh, concurring separately, said the USPS rule might fall within the agency's statutory authority, but that implementing it in time for the 2026 election would be unlawful under the Administrative Procedure Act, as state and local officials had not been given enough time to comply.

The order leaves in place a preliminary injunction issued by a federal judge in Boston on 4 September, which the First Circuit Court of Appeals later declined to stay. The appeals court found the rule was likely unlawful and that states faced serious practical difficulties in implementing it before the election.

How the Legal Fight Began

The case stems from an executive order signed on 31 March directing the Postmaster General to begin rulemaking on uniform standards for federal election ballot mail, including requirements on ballot-envelope design and the submission of lists of voters receiving mail ballots. The order envisaged states submitting such lists at least 60 days before a federal election.

The Postal Service published its final rule on 26 August. It required states using federal ballot mail to meet specified envelope standards and to submit voter information through a USPS portal.

Unlike the executive order, the final rule adopted a more flexible standard, generally calling for initial voter information at least 30 days before an election 'to the extent practicable', or by the date ballots could begin being mailed under state law, with supplemental submissions allowed later.

Outbound ballot mailings that failed to meet the requirements would generally not be accepted into the mailstream and could be returned to election officials for correction. The Postal Service said it would not determine voter eligibility or whether a completed ballot should be counted; that responsibility remained with state and local officials.

States and voting-rights groups first challenged the executive order itself, but the Supreme Court found that dispute premature, as the Postal Service had not yet issued or implemented a final rule. Once the rule was published, plaintiffs argued the alleged harms were now concrete enough to support judicial review, and litigation resumed.

What the Supreme Court Did And Left Open

The 14 September order does not finally resolve whether the Postal Service had the statutory authority to issue the rule. That question remains open in the continuing litigation. Justice Kavanaugh's concurrence made clear there was, in his view, 'at least a fair prospect' the rule fell within USPS's authority, even as he agreed its rollout for this year's election could not proceed.

Election officials and voting-rights organisations had warned that the 30-day timetable risked clashing with state voter-registration and ballot-request deadlines, which vary widely and in some states extend much closer to polling day. They also raised concerns that rejected or delayed mailings could prevent some ballots from reaching voters or election offices in time to be counted.

For now, the injunction prevents the administration from enforcing the challenged rule for the 2026 midterm elections, meaning states will continue using their existing mail-voting procedures. The broader legal questions remain unresolved as the underlying case continues in the lower courts.