Supreme Court upholds state laws counting mail ballots that arrive after Election Day

The Supreme Court on Monday upheld a Mississippi law that counts mail ballots received after Election Day, as long as they are postmarked by Election Day and arrive within five business days. The 5-4 decision in Watson v. Republican National Committee rejects the argument that federal law requires every mail ballot to be in hand by the close of Election Day, and it leaves grace-period laws in other states in place about four months before the 2026 midterm elections.

What the court decided

Justice Amy Coney Barrett wrote the majority opinion, joined by Chief Justice John Roberts and Justices Sonia Sotomayor, Elena Kagan, and Ketanji Brown Jackson. Barrett wrote that the federal statutes setting a single national Election Day fix the deadline for casting a vote, not the deadline for when an election office must receive it. "Election-day statutes say nothing about ballot receipt, and we cannot add to the words Congress chose," she wrote.

The majority held that Mississippi satisfies federal law because voters there must cast their ballots by Election Day. "The electorate's choice is made when voting is complete, not when ballots are received," Barrett wrote.

Justice Samuel Alito dissented, joined by Justices Clarence Thomas, Neil Gorsuch, and Brett Kavanaugh. Alito wrote that counting ballots that arrive later moves the moment the public's decision is made past the day Congress set. "The acceptance of these late-arriving ballots effectively postpones the date on which the electorate's choice is made," he wrote.

The law and the lawsuit

Mississippi passed the law in 2020, during the COVID-19 pandemic. It counts an absentee ballot that is postmarked on or before Election Day and reaches the county within five business days.

In 2024, the Republican National Committee and the Mississippi Republican Party, joined by a Mississippi voter and a county election official, sued in federal court in Gulfport to strike the deadline. The Libertarian Party of Mississippi filed a similar suit that was combined with the first. They argued the state law conflicts with the federal law, first passed in 1845, that sets the Tuesday after the first Monday in November as the day to choose presidential electors and members of Congress.

Senior U.S. District Judge Louis Guirola Jr. upheld the law. He wrote that Congress set a single Election Day to keep voters from having to go to the polls on different days for state and federal races, and to keep results in one state from influencing voting in another. "Neither of those concerns is raised by allowing a reasonable interval for ballots cast and postmarked by election day to arrive by mail," he wrote.

The 5th U.S. Circuit Court of Appeals reversed, holding that federal law requires all ballots to be received by Election Day. The full appeals court declined to rehear the case over a dissent from five judges. The Supreme Court agreed in November to take it up, heard argument, and on Monday reversed the 5th Circuit.

What it changes

The ruling keeps existing grace-period laws on the books. Fourteen states and the District of Columbia count mail ballots that are postmarked by Election Day but arrive afterward, NPR reported, with windows that run from a few days to about two weeks. Illinois counts ballots received up to 14 days later, California allows seven days, and Mississippi allows five business days. About 30 states keep a later-arrival window for ballots from military members and citizens living overseas, according to NPR.

The decision also points to the outcome of a companion case, Bost v. Illinois State Board of Elections. The court had ruled that Rep. Michael Bost, an Illinois Republican, could bring a challenge to his state's 14-day receipt window. The reasoning in Watson means that challenge will fail.

The 2026 midterm elections are set for November 3.