March 23 (Reuters) – The U.S. Supreme Court is set on Monday to hear Mississippi’s defense of a state law challenged by Republicans that allows a five-day grace period for mail-in ballots received after Election Day to be counted in a case that could lead to stricter voting rules around the country.
Republican President Donald Trump’s administration is backing the challenge to Mississippi’s law, which permits mail-in ballots sent by certain voters to be counted if they were postmarked on or before Election Day but received up to five business days after a federal election. Absentee voting by mail is limited to a few categories of voters under the law including elderly people, the disabled and those living away from home.
The Supreme Court is due to hear arguments in Mississippi’s appeal of a lower court’s ruling that deemed the law illegal.
Trump last year vowed to end the use of mail-in ballots nationwide before the 2026 U.S. midterm elections, a move that likely would disproportionately benefit his party given that Democratic voters traditionally have been more likely to use mail-in ballots than Republican voters.
Republicans have taken a skeptical view toward mail-in ballots. Trump has sought to cast doubt on the security of these ballots, although evidence of voter fraud is rare. Trump has continued to make false claims of widespread voting fraud in the 2020 presidential election that he lost to Democrat Joe Biden.
About 30 states and the District of Columbia accept at least some ballots that are postmarked on or before Election Day but received afterward.
The Republican National Committee, the Mississippi Republican Party and other plaintiffs filed a lawsuit in 2024 seeking to invalidate Mississippi’s law.
During the first year of the COVID pandemic, the Republican-controlled Mississippi legislature in 2020 passed the law on a bipartisan basis.
The New Orleans-based 5th U.S. Circuit Court of Appeals in 2024 ruled in favor of the Republican challengers. It declared that the measure was preempted by federal laws setting Election Day for federal elections as the “day by which ballots must be both cast by voters and received by state officials.”
Federal law “does not permit the state of Mississippi to extend the period for voting by one day, five days or 100 days,” the 5th Circuit stated.
The 5th Circuit did not immediately block Mississippi’s procedures, but instead sent the case back to a trial judge for further review. The litigation is currently on hold pending the Supreme Court’s consideration.
Though the 5th Circuit’s action applied only in the three states where the regional federal appeals court has jurisdiction – Mississippi, Louisiana and Texas – it called into question the voting practices in the other states with similar mail-in ballot policies.
The 5th Circuit’s decision would “override countless state laws from the past 165 years and largely require citizens to vote in person, on Election Day, in their home districts, without the secret-ballot system,” Mississippi said in its appeal.
(Reporting by Andrew Chung; Editing by Will Dunham)
Copyright 2026 Thomson Reuters.