Supreme Court tackles the question of late-arriving mail-in ballots

With mail-in voting growing in popularity, one of the questions that has arisen is the ability of election boards to count votes postmarked before Election Day but received afterwards. In Watson v. Republican National Committee, the Supreme Court will consider that question on March 23, 2026, in a case coming from Mississippi.

Last fall, the Court also heard arguments in Bost v. Illinois State Board of Elections, a case about who can contest late-received ballots. In a 7-2 decision issued in January 2026, the Supreme Court—in an opinion by Chief Justice John Roberts—overturned a lower-court decision from Illinois that prevented a political candidate from challenging a state law that allowed postmarked ballots received up to two weeks after Election Day. Roberts said Michael Bost and two others had Article III standing under the Constitution to challenge the law permitting the late-arriving ballots.

Now, the Supreme Court turns to a related question: Do federal laws preempt a state law that allows ballots cast by federal election day to count if officials receive them after election day?

The Election Clause and the Watson Case

The Constitution’s Article 1, Section 4, the Elections Clause, allows individual states to establish the “Times, Places and Manner of holding Elections for Senators and Representatives.” However, Congress can at “any time by Law make or alter such Regulations.” Congress has passed statutes 2 U.S.C. § 7, 2 U.S.C. § 1, and 3 U.S.C. § 1, that set the Tuesday after the first Monday in November, in every even-numbered year, as the “election” day for federal offices. This year, the federal election day is Nov. 3, 2026.

In Watson, the state of Mississippi permits mail-in absentee ballots to be received and counted after Election Day in certain circumstances. The 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.” Mississippi Secretary of State Michael Watson is contesting a Fifth Circuit Court of Appeals decision striking down the late-counting provision of the state law.

In 2024, the Republican National Committee, the Mississippi Republican Party, and others sued Watson in his capacity as Mississippi Secretary of State and several county officials. They believe only federal statutes defining the power of Congress to set the date for federal elections can permit the counting of ballots received after election day. The state law, they argue, violates the rights of candidates to stand for office protected by the First and 14th Amendments.

A federal district court agreed with the state of Mississippi, deciding there was not a conflict between the state law and the federal statutes. The court explained, “All that occurs after election day is the delivery and counting of ballots cast on or before election day.” However, three Fifth Circuit judges came to a different conclusion. Citing text, precedent, and history, the judges ruled that federal election day “is the day by which ballots must be both cast by voters and received by state officials.” The full Fifth Circuit denied a case rehearing in a 10-5 vote. The Supreme Court accepted the case on Nov. 10, 2025.

The Arguments at Court

In their most recent brief at the Court, Mississippi state attorney general Lynn Fitch and solicitor general Scott G. Stewart note that most states allow timely cast ballots to be counted if election officials receive the ballots soon after election day. In their view, an election happens at the time when voters fill out and submit a ballot. They cite Newberry v. United States (1921), when Justice James Clark McReynolds concluded the word “election” “now has the same general significance as it did when the Constitution came into existence — [the] final choice of an officer by the duly qualified electors.” The brief also cites similar examples from historical dictionaries.

“An election thus occurs when voters make their choice of officers and that choice is conclusive—final. Under the federal election-day statutes, then, election day is the day by which voters must conclusively choose federal officers,” the state of Mississippi argues. “An election thus does not depend on when ballots are received.”

The state of Mississippi also points to the potential nationwide impact of letting the Fifth Circuit’s ruling stand. “The rule the court of appeals adopted would doom the laws of the nearly 30 States that today accept some ballots after election day—including for military voters,” it concluded. The state cites the Uniformed and Overseas Citizens Absentee Voting Act (UOCAVA), a law that permits the late receival of overseas military and absentee ballots.

The respondents paint a much different picture. Gilbert C. Dickey, counsel for the Republican National Committee and the Republican Party of Mississippi, tells the court that “[w]hen Congress designated a single ‘day for the election,’ it set a deadline. If a state law extends the election after that deadline, it conflicts with Congress’s timing decision and to that extent is void.”

Dickey cites Foster v. Love (1997), a Supreme Court decision in which Justice David Souter writing for a unanimous court said that Louisiana’s open primary system improperly extended an election deadline set by Congress and thus conflicted with the intent of lawmakers.

Unlike the state of Mississippi, Dickey believes that “the election concludes when all ballots are received,” and that the Fifth Circuit correctly held that Mississippi’s law allowing late-arriving ballots to be counted is void. “The election-day statutes govern when States must close the ballot box, not when voters must make their selection,” Dickey says.

Dickey also cites a concurring opinion from Justice Brett Kavanaugh in DNC v. Wisconsin State Legislature (2020), which said that “[f]or important reasons, most States, including Wisconsin, require absentee ballots to be received by election day, not just mailed by election day. Those States want to avoid the chaos and suspicions of impropriety that can ensue if thousands of absentee ballots flow in after election day and potentially flip the results of an election.”

The Issues at Stake

The outcome of Watson v. Republican National Committee will be closely watched with a federal election to be held this November, and especially if the Court’s decision is announced in late June 2026. The Court’s majority could strike down the Mississippi law on narrow grounds, invalidate similar state laws, uphold Mississippi’s right to determine how it counts mail-in, absentee, and overseas votes, or return the case to lower courts for reconsideration.

In either event, it may not be the last time the nine justices confront related issues since its decision in Bost gives aggrieved federal candidates the right to pursue similar legal claims. The biggest question will be if the Court will provide guidance or a rule that will be in place on Nov. 3, 2026, to help local election officials deal with late-arriving votes.

Scott Bomboy is the editor in chief of the National Constitution Center.