A exterior of a voting booth in Beaver County, Pennsylvania.
Changes to mail-in and absentee ballot envelopes will make it easier for Bucks County voters and Board of Elections staff to spot “naked” ballots before Election Day.

WASHINGTON − The Supreme Court will decide whether mailed ballots must be received by Election Day and not just postmarked by then, agreeing to review the Republican Party’s so-far successful challenge to a Mississippi law that could affect similar rules in many other states.

In asking the court to hear their appeal, lawyers for Mississippi warned there could be “electoral chaos” nationwide unless the justices stop the GOP challenge before the next election.

The Republican National Committee said it’s states like Mississippi that are risking chaos because absentee ballots received after Election Day can flip the results, leading to distrust in elections.

In addition to the Republican Party's various challenges to state laws, President Donald Trump has sought to block states from accepting mailed ballots after Election Day. He issued an executive order in March that is being contested in separate litigation.

Mississippi's appeal is the fourth case the high court agreed to hear this term that could affect future elections.

The justices are also deciding whether to overturn restrictions on coordinated spending between parties and candidates, whether to curtail protections against racial discrimination in voting, and when candidates can contest an Illinois election law similar to Mississippi’s.

Sixteen states allow ballots postmarked by Election Day but received after it to be counted, according to the National Conference of State Legislatures. Other states have similar rules just for military service members or for all voters living overseas.

In Mississippi, any absentee ballot that is mailed on or before Election Day can be received up to five business days after the election.

Republicans argue that such rules violate federal law, which sets a specific date for U.S. elections.

Attorneys for Mississippi counter that the “election” is when voters make their choice. As long as they do that through a ballot postmarked by the federally designated day, their vote should be counted, Mississippi Attorney General Lynn Fitch told the Supreme Court.

Groups representing veterans and retired Mississippians joined the state’s defense of the law.

“Our legislature got it right when they said that no voter should have their ballot thrown out simply because of delays in the mail,” James Sims, president of the Mississippi Alliance for Retired Americans, said when the group joined the case after Republicans and the Libertarian Party of Mississippi challenged the law in 2024.

A federal district judge upheld Mississippi’s law last year, but the Louisiana-based 5th U.S. Circuit Court of Appeals sided with the challengers. A panel of appeals court judges said election day “is the day by which ballots must be both cast by voters and received by state officials.”

Although the state and national Republican parties are challenging Mississippi’s law, it was approved by the GOP-controlled legislature and is being defended by Fitch, a Republican.

The high court is expected to hear the case next year and issue an opinion by summer.

This story has been updated.

This article originally appeared on USA TODAY: Supreme Court to decide major challenge to mail-in ballots in case started by GOP

Reporting by Maureen Groppe, USA TODAY / USA TODAY

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