The Supreme Court’s March 2026 oral arguments in Watson v. Republican National Committee have driven the current 69% implied probability that the Court will bar states from counting mail ballots received after Election Day. During the session, the conservative majority voiced skepticism that federal statutes setting Election Day as the deadline allow grace periods for postmarked ballots arriving days later, a practice now used in 14 states. A ruling is expected by late June or early July, potentially requiring immediate policy shifts ahead of the 2026 midterms and prompting election officials to adjust deadlines and voter communications. This judicial posture, reflecting a textualist reading of federal Election Day requirements, has shaped trader consensus without a final decision yet issued.