Supreme Court Ruling Could Prove Decisive in Mississippi's Razor-Thin Senate Race

Mississippi's razor-thin Senate election could hinge on a Supreme Court ruling issued just four months ago that allows absentee ballots arriving after Election Day to be counted.

Democrat Scott Colom held a narrow lead of fewer than 2,000 votes over Republican incumbent Cindy Hyde-Smith on Thursday, with approximately 3,600 mail-in absentee ballots still outstanding – enough to potentially change the result. The ballots must be postmarked by Election Day and reach the circuit clerk’s offices by Nov. 10.

The five-day grace period survived a Republican legal challenge when the Supreme Court ruled 5–4 in June that federal law does not require mail-in ballots to arrive by Election Day.

Eligible absentee voters in Mississippi, like senior citizens, people with disabilities, incarcerated people who remain eligible to vote, and those who reside outside their home county, received 122,590 ballots from the state for this election. As of the night before the midterms, 116,453 of these absentee ballots had already been returned.

NBC News estimates that roughly 45,000 votes remain uncounted in Mississippi, including 10,000 to 15,000 affidavit ballots, according to the Colom campaign. These are cast by voters whose eligibility cannot immediately be verified at the time. Voters who lacked ID have until Nov. 10 to present it, while election officials review other affidavit ballots to determine whether they qualify.

In 2024, the Republican National Committee (RNC) and the Mississippi Republican Party sued Mississippi to try to prevent the state from counting absentee ballots postmarked by Election Day but received afterward. Mississippi is among 30 states which allow for absentee ballots that have been mailed by Election Day but received after to be counted.

The RNC’s main argument centered on the definition of the word election, alleging that an election constitutes both the casting and receiving of a ballot. So, a ballot received after Election Day, even if it was postmarked by the correct date, should not be allowed. The Fifth Circuit Court of Appeals, which has federal jurisdiction in Mississippi, agreed with the RNC. The Supreme Court, however, did not.

The Supreme Court’s decision came down on June 29, reversing the Fifth Circuit's finding. Justice Amy Coney Barrett wrote the majority opinion, joined by Chief Justice John Roberts and Justices Sonia Sotomayor, Elena Kagan and Ketanji Brown Jackson. According to Barrett, the case came down to the different roles of the federal and state governments when running congressional elections.

“While federal law dictates when the ballots must be cast, state law governs when they must be received,” Barrett wrote. In the decision, Barrett likewise explained that an election does not describe the act of casting and receiving a ballot, but rather the deadline for the electorate to choose a candidate. Election Day, Barrett contended, is the deadline to choose.

President Donald Trump deemed the court’s ruling a “tremendous loss” in a Truth Social post, and has continued to call for additional voting regulations, including proof of citizenship, voter ID, paper ballots and one-day voting.

In a Nov. 4 post on Bluesky, Democracy Docket – founded by Marc Elias, whose law firm is leading legal efforts for the Colom campaign – criticized the RNC’s attempt to test the waters of absentee ballot policies with their Mississippi lawsuit. “The RNC went shopping for the perfect place to sue over mail ballots that arrive after Election Day, even if they were cast on time,” Democracy Docket wrote.

Additionally, the RNC’s lawsuit narrowed Hyde-Smith’s ability to challenge the result should she lose by a tight margin. Because the Supreme Court has already ruled on the permissibility of absentee votes received after Election Day, the RNC’s lawsuit reduced the possible pathways that Hyde-Smith could use to challenge a narrow Colom victory.

Unlike most states, Mississippi has no procedure for a recount in a U.S. Senate race. Consequently, candidates must assert a due process or other constitutional violation – for instance by challenging “decisions to exclude or to include certain ballots in the tabulation under state or federal law,” as election law scholar Derek Muller explained — to force a recount.

Mississippi counties must certify their election results by Nov. 13. The state’s deadline is Dec. 3.