Updated November 11, 2025 at 8:11 AM MST
The U.S. Supreme Court announced Monday it will hear a case that could decide whether states can count postmarked mail ballots that arrive after Election Day — something that about 20 states and territories currently allow.
Mississippi is one of those states, and in June, its top election official asked the court to hear a lawsuit filed by the Republican National Committee that argues the state's five-day mail ballot grace period violates federal law.
An appeals court sided with the RNC. The ruling, which came while voters were casting ballots in last year's presidential election, did not go into effect immediately.
Sixteen states plus Guam, Puerto Rico, the Virgin Islands and Washington, D.C., currently accept and count mail-in ballots that are received after Election Day — typically, only if those ballots are postmarked on or before Election Day. More states have grace periods like that just for military and overseas voters.
States provide this wiggle room to voters in case they forget to return their mail ballots ahead of time, if there are issues with the postal service, or if there are other unforeseen issues like bad weather and natural disasters.
The GOP has argued that Congress alone — not states — has the right to decide when elections end, and that Congress established a uniform Election Day.
The RNC filed multiple legal challenges to various state grace period laws ahead of the 2024 election, including in the swing state of Nevada. Since then, GOP-led states including Utah have eliminated their mail ballot grace periods, and President Trump has sought to end them nationally via executive order.
During the 2024 election, hundreds of thousands of mail ballots were counted that were received by officials after Election Day. In Washington state, for instance, where the vast majority of voters cast mail ballots, officials reported that "more than 250,000 Washington ballots postmarked on time arrived after Election Day."
Joyce Vance, a professor at the University of Alabama School of Law, told NPR last year that Republicans are "trying to set up a possible rule for the future where only ballots that are cast and counted on Election Day count," which she said made more sense for voting patterns a hundred years ago.
"It doesn't reflect the modern reality where we have early voting days and have mail-in voting days precisely to accommodate the fact that not everybody can get away during normal business hours on a Tuesday to vote," she said.
The Mississippi case becomes the third related to voting taken up by the Supreme Court this term.
Justices are considering another mail-ballot case that centers on whether candidates have standing to sue over voting regulations, and a high-profile challenge to the Voting Rights Act.
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