The U.S. Supreme Court on Monday left intact a lower court decision blocking the U.S. Postal Service from enforcing new regulations for mail voting in the November 2026 midterm elections, rejecting an emergency push by the Trump administration to implement the requirements.
In a brief unsigned order, the high court determined that the government “is unlikely to succeed on the merits of its challenge to the District Court’s preliminary injunction.” The decision keeps the implementation of the new Postal Service rules on hold while ongoing legal challenges proceed through the courts, clearing the way for states to continue sending out mail-in ballots as planned.
Mail ballots have already gone out to voters in some states, and election officials at both state and local levels had warned that adapting to the new postal requirements in time for the upcoming elections would prove extraordinarily difficult.
## Legal Arguments and Court Division
The Trump administration defended the regulations as “plainly constitutional,” arguing they impose only modest design and review requirements on states. Solicitor General D. John Sauer argued in court filings that the rules address the risk of fraud in mail voting, which he described as a “particularly pernicious species of fraud” that dilutes lawful votes and undermines public confidence. The administration did not present evidence of widespread voter fraud in its filings, and President Donald Trump himself has voted by mail in Florida elections this year.
Democratic-led states and voting rights groups challenged the rules, arguing they unconstitutionally infringe on states’ authority to administer elections and that the Postal Service lacks the power to set rules for federal elections. In court briefs, the challengers warned that complying with the new standards in time for the midterms would be “impossible” and would lead to “chaos,” with millions of voters potentially disenfranchised due to technical breakdowns and delays.
The Supreme Court’s justices split on the matter, resulting in a fractured bench. Justices Samuel Alito and Clarence Thomas dissented from the majority. In an eight-page dissent, Justice Alito wrote that the policy falls within the Postal Service’s broad authority to regulate the mail and that the agency is broadly exempted from administrative law challenges regarding “arbitrary and capricious” actions. Both dissenting justices concluded that the plaintiffs failed to meet the high bar required to block the policy, characterizing the legal challenge against it as a “Hail Mary pass.”
Justice Brett Kavanaugh sided with the majority to block the rules, though he parted ways with the challengers’ core rationale regarding statutory authority. In his opinion, Justice Kavanaugh wrote that “there is at least a fair prospect that the final rule falls within the Postal Service’s statutory authority.” However, he concluded that applying the rule in the 2026 midterm 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.”
## Implementation Hurdles and Next Steps
Under the finalized Postal Service regulations, mail ballot envelopes must meet specific design standards, including unique barcodes. Additionally, state and local election officials are required to submit voter information—such as names and home addresses—to an online portal for individuals receiving mail ballots. Postal workers would then deliver only those ballots addressed to voters appearing on the state-provided list, with the agency warning that non-compliant ballot mailings would be rejected and returned to election offices.
With the preliminary injunction remaining in place, the immediate legal barrier to mailing out midterm ballots has been removed. The underlying litigation over the Postal Service regulations continues to move forward, with the broader legal battle effectively deferred beyond the November contest.
