The Supreme Court heard oral arguments Monday in Watson v. Republican National Committee, a case centered on whether states may count mail-in ballots that arrive after Election Day if they were postmarked by Election Day. Mississippi allows such ballots to be counted up to five days after the election — a policy shared by 13 other states and Washington, D.C. Conservative justices signaled strong skepticism of the practice. Fox News reported that Chief Justice John Roberts asked, "If Election Day is the voting and taking, then it has to be that day." Justice Samuel Alito drew an analogy to other national holidays — Labor Day, Memorial Day, George Washington's Birthday — arguing each refers to a single calendar day. NBC News confirmed the conservative justices' posture, reporting that the case could affect voting procedures in more than 30 states ahead of the November midterms for House and Senate control.

Justice Brett Kavanaugh, citing election-integrity concerns, warned that delayed ballot counting could undermine public confidence: "If the apparent winner the morning after the election ends up losing due to late arriving ballots, charges of a rigged election could explode." The Trump administration argued in an amicus brief that late-ballot rules erode voter confidence. Mississippi Attorney General Lynn Fitch countered that the election legally occurs when voters cast ballots — not when officials receive them — and emphasized that the stakes are high in close races. Justice Amy Coney Barrett, a potential swing vote, questioned whether federal law actually prohibits the practice, even while acknowledging "really good policy reasons" for requiring Election Day receipt.

Liberal justices pushed back sharply. Justice Elena Kagan called it "inconceivable" to reject a practice now entrenched across roughly 30 states. Justice Ketanji Brown Jackson warned the court against resolving a policy question that Congress should address through legislation. The case also affects military and overseas voters: 29 states allow extended deadlines specifically for those constituencies, creating a potentially awkward line-drawing problem if the court rules broadly against late-arriving ballots.

A notable sidebar to the case: NBC News reported that President Trump himself cast a mail ballot in Florida's recent special election, even while publicly calling mail voting "mail-in cheating." The White House called it a "non-story," noting Trump is a Florida resident. The Daily Wire reported the SCOTUS ruling could be the most consequential election-procedure decision since Bush v. Gore. Hundreds of thousands of mail ballots arrived after Election Day in 2024 and were counted under existing state laws; a ruling for the RNC could force rapid system changes before November 2026.