The dispute centers on an executive order Trump issued in March directing the Postal Service to develop new requirements for delivering mail-in ballots. The resulting rules would require states to submit information about eligible mail voters through a federal online system and use standardized ballot envelopes with voter-specific Intelligent Mail barcodes. The Postal Service would be able to refuse delivery of ballots that did not meet the requirements. 

The administration argued that the Postal Service had the authority to regulate ballot delivery and that the new procedures could be implemented before the election. Democratic-led states, voting rights organizations and other challengers argued that the measures exceeded federal authority over elections and could prevent valid ballots from reaching voters. Federal judges in Massachusetts and Washington, D.C., blocked enforcement, citing legal concerns and the limited time available for election officials to adapt. 

The Supreme Court’s action maintains the existing system as mail voting is already underway in some states, including Alabama, North Carolina and Wisconsin. The ruling is significant because nearly one-third of U.S. voters cast ballots by mail in the 2024 presidential election, making the delivery of absentee and mail-in ballots an important part of the electoral process.