The Supreme Court’s March 2026 oral arguments in Watson v. Republican National Committee have shaped trader consensus on whether the Court will bar states from counting mail ballots received after Election Day. During those proceedings, a conservative majority signaled that federal statutes setting Election Day as the Tuesday after the first Monday in November require ballots to be both cast and received by that date, casting doubt on grace periods in Mississippi and roughly a dozen other states. A ruling is expected by late June or early July, potentially affecting November midterm procedures in multiple jurisdictions. This procedural posture and the Court’s expressed concerns over uniform federal deadlines have driven the current 71% implied probability for a bar on post-Election Day counting.