SCOTUS Blocks USPS Mail-Ballot Rule Less Than 2 Months Before Midterms

For election-law and administrative-law practitioners, the order is less about the merits and more about the intersection of APA review, equitable stays, and election-timing principles. Justice Kavanaugh's opinion previews a roadmap: agencies can win on statutory authority but still lose on timing and implementation burdens. The conservative split reveals unresolved tensions on the Supreme Court's emergency docket.

The Supreme Court on Monday night declined to lift a nationwide preliminary injunction that blocks the U.S. Postal Service from implementing new mail-in ballot requirements for the November 2026 midterm elections. The unsigned order held that the Trump administration "is unlikely to succeed on the merits of its challenge to the" preliminary injunction issued by a federal judge in Boston in late August. The practical effect is that the USPS rule—developed under a March executive order—will not govern how state and local officials handle mail ballots this cycle.

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Two of the court's conservatives, Justices Samuel Alito and Clarence Thomas, dissented from the denial.

The contested rule would have established new standards for ballot envelopes and required states to create lists of voters eligible to receive mail ballots. Critics argued this would make voting by mail more difficult. The administration sought emergency relief at the high court, asking it to stay the district court's injunction so the rule could apply nationwide. The Supreme Court's denial leaves the status quo in place less than two months before an election that will decide control of both chambers of Congress, where Republicans currently hold slim majorities.

Justice Brett Kavanaugh, a Trump appointee, wrote separately to explain his concurrence in the denial. He said there "is at least a fair prospect that the final rule falls within the Postal Service's statutory authority." But, he continued, applying the rule in the 2026 elections "would be arbitrary and capricious in violation of the Administrative Procedure Act because state and local election officials do not have sufficient time to reasonably implement the rule before the elections." That framing is significant: it separates statutory authority from implementation timing. Kavanaugh did not endorse the rule's policy or full legality; he simply refused to let it take effect on the eve of a federal election.

The order's narrowness matters. The Supreme Court explicitly noted its decision only prevents the Postal Service rule from being used in November's elections. It did not strike down the rule, and the litigation over the rule's merits can continue. This leaves open the possibility that a later administration or the courts could allow a similar rule for future election cycles, provided there is sufficient lead time and the rule survives APA review. For election administrators and state officials, the ruling provides immediate relief from compliance obligations, but not permanent certainty.

Two of the court's conservatives, Justices Samuel Alito and Clarence Thomas, dissented from the denial. Their dissent signals an ongoing division on the emergency docket over how courts should handle election-related administrative rules. The order did not state the full vote or join line, but the public dissents indicate at least two justices would have granted the stay. The absence of a publicly noted vote from the other six justices leaves the exact alignment unclear, though Kavanaugh's concurrence suggests he was a decisive but case-specific vote.

The legal standards at play are important. To obtain a stay of a preliminary injunction in the Supreme Court, the applicant generally must show a likelihood of success on the merits, irreparable harm, and equities weighing in its favor. The unsigned order said the administration was unlikely to succeed on the merits "of its challenge to the" injunction—a somewhat opaque phrase that may refer to the challenge to the injunction itself rather than the underlying rule. Kavanaugh's concurrence clarified his view: the Postal Service might have statutory authority, but the timing made the rule arbitrary and capricious under the APA. That distinction avoids deciding the full merits while still denying emergency relief.

The decision also echoes the so-called Purcell principle, under which courts are reluctant to change election rules close to an election. Kavanaugh did not name Purcell, but his reasoning—that election officials lack sufficient time to reasonably implement the rule—tracks that concern. The Supreme Court in recent years has repeatedly grappled with late-breaking election rule changes, and this order continues the trend of courts acting cautiously as Election Day approaches.