4 WATSON v. REPUBLICAN NATIONAL COMMITTEE Opinion of the Court expanded throughout the 20th century, and today, every State lets at least some residents vote absentee. In fact, federal law requires States to permit absentee voting in certain circumstances. See 52 U. S. C. §10502(d). Due dates for absentee ballots have shifted over time. During the Civil War, States that allowed absentee voting imposed an election-day deadline for ballot receipt. See infra, at 11–12. But during World War I, States began counting absentee ballots received after election day. See 1918 Md. Laws p. 130; 1919 Kan. Sess. Laws pp. 252–253; see also Cal. Political Code ch. 14, §§1359(b)–(c), 1360, pp. 363– 364 (1923). Today, roughly 30 States count at least some absentee ballots mailed by election day but received afterward. See National Conference of State Legislatures, Table 11: Receipt and Postmark Deadlines for Absentee/Mail Ballots (May 18, 2026), https://www.ncsl.org/elections-andcampaigns/table-11-receipt-and-postmark-deadlines-forabsentee-mail-ballots. Mississippi is among them. In Mississippi, certain residents, like college students away from home and senior citizens, may vote in federal elections by absentee ballot. Miss. Code Ann. §23–15–713 (Cum. Supp. 2025). These voters may dispatch their ballots by mail or common carrier. See §§23–15–637(1)(a), (3). All absentee ballots must be “postmarked on or before the date of the election and received by the registrar no more than five (5) business days after the election.” Ibid. In 2024, the Republican National Committee, the Mississippi Republican Party, and various individuals sued the Mississippi secretary of state and several election officials, contending that federal law prevents Mississippi from counting absentee ballots received after election day. According to plaintiffs, the election-day statutes use the word “election” to refer to two acts: ballot casting and ballot receipt. So by setting the day for the “election,” plaintiffs argue, these statutes set the deadline for both. The