Cite as: 609 U. S. ____ (2026) 1 Opinion of the Court NOTICE: This opinion is subject to formal revision before publication in the United States Reports. Readers are requested to notify the Reporter of Decisions, Supreme Court of the United States, Washington, D. C. 20543, pio@supremecourt.gov, of any typographical or other formal errors. SUPREME COURT OF THE UNITED STATES _________________ No. 24–1260 _________________ MICHAEL WATSON, MISSISSIPPI SECRETARY OF STATE, PETITIONER v. REPUBLICAN NATIONAL COMMITTEE, ET AL. ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE FIFTH CIRCUIT [June 29, 2026] JUSTICE BARRETT delivered the opinion of the Court. Three federal statutes set the day for the election of Representatives, Senators, and the President. A Mississippi law permits the counting of absentee ballots postmarked by election day but received up to five days later. We must decide whether the federal election-day statutes preempt Mississippi’s law. They do not. I A The Constitution’s Elections Clause empowers state legislatures to “prescrib[e]” the “Times, Places and Manner of holding” congressional elections. Art. I, §4, cl. 1. Congress may “ ‘override’ ” most of these choices. Foster v. Love, 522 U. S. 67, 69 (1997) (quoting U. S. Term Limits, Inc. v. Thornton, 514 U. S. 779, 833 (1995)). By “default,” however, “responsibility for the mechanics of congressional elections” belongs to States. Foster, 522 U. S., at 69. As Alexander Hamilton put it, the Constitution lodges power over congressional elections in state legislatures “primarily” and