Mississippi Mail-In Ballot Lawsuit: Supreme Court Case Explained

The Mississippi mail-in ballot lawsuit is a case now before the U.S. Supreme Court, Watson v. Republican National Committee, that asks whether states can count absentee ballots mailed by Election Day but received a few days later. It began as a Republican National Committee challenge to a Mississippi law giving mailed absentee ballots a five-business-day grace period to arrive. The Court heard argument on March 23, 2026, and a decision is expected by the end of the term. The ruling could reshape mail voting rules in roughly 30 states.

What the Mississippi Law Does

Mississippi counts a mail-in absentee ballot if it is postmarked on or before Election Day and received by the county registrar within five business days afterward. The rule dates to House Bill 1521, passed in 2020, and was made a permanent feature of state election law through 2024 legislation.¹²

Mississippi’s absentee system is otherwise restrictive. Mail absentee voting is limited to specific categories, including voters temporarily outside their county, people with disabilities, voters aged 65 and older, and certain incarcerated individuals. The application generally requires a notarized witness signature.³

How the Case Reached the Supreme Court

In January 2024, the Republican National Committee and the Mississippi Republican Party sued in the U.S. District Court for the Southern District of Mississippi. They argued that three federal statutes — 2 U.S.C. § 1, 2 U.S.C. § 7, and 3 U.S.C. § 1 — set a single Election Day for federal offices, and that counting ballots received after that day effectively extended the election past the congressional deadline. They also argued that because mail voting tends to skew Democratic, the grace period disadvantaged Republican candidates.⁴

The Vet Voice Foundation and the Mississippi Alliance for Retired Americans intervened to defend the law. In July 2024, U.S. District Judge Louis Guirola Jr. granted summary judgment for the defendants, finding that “election” in federal law refers to the act of casting a ballot, not receiving it, so the Mississippi statute did not conflict with federal law.⁵

A three-judge panel of the Fifth Circuit reversed in October 2024. Drawing on the Supreme Court’s 1997 decision in Foster v. Love, the panel held that federal Election Day statutes require ballots to be both cast and received by the close of Election Day, reasoning that an election is not “consummated” until officials possess the ballots. The full court denied rehearing en banc by a 10–5 vote in March 2025.⁶

Mississippi Secretary of State Michael Watson petitioned for review. The Supreme Court granted certiorari on November 12, 2025, docketing the case as Watson v. Republican National Committee, No. 24-1260.⁵⁷

The Legal Question

The question presented is whether the federal Election Day statutes — 2 U.S.C. § 7, 2 U.S.C. § 1, and 3 U.S.C. § 1 — preempt a state law allowing ballots cast by federal Election Day to be received by election officials after that day.⁷

Mississippi’s Argument

Watson argues that federal law only requires voters to cast their ballots by Election Day, and that casting occurs when a voter marks and submits a ballot, not when officials physically receive it. Counting, on this view, is inherently a post-Election-Day activity. Watson also points to state authority over election mechanics and to Congress’s historical practice of deferring to state-set receipt deadlines, citing the Uniformed and Overseas Citizens Absentee Voting Act of 1986. He warned that the Fifth Circuit’s rule would invalidate laws in roughly 30 states and the District of Columbia.⁸⁹

The RNC’s Argument

Paul Clement, arguing for the RNC, told the Court that an election is complete only when all ballots are in officials’ hands and the ballot box is closed. He said that when Congress fixed a uniform Election Day in the 1800s, casting and receipt were inseparable because voters placed paper ballots in a box in front of an official, and that there is an “unbroken historical tradition” from the 19th and early 20th centuries requiring receipt by Election Day. Clement also argued that grace periods “hampered the efficiency and integrity of elections.”¹⁰¹¹

U.S. Solicitor General D. John Sauer appeared as amicus for the United States on the side of the RNC. In March 2025, President Trump had signed an executive order directing the Attorney General to enforce federal Election Day statutes against states counting mail ballots received after Election Day, citing the Fifth Circuit’s ruling.¹²¹³

What the Oral Argument Signaled

Mississippi Solicitor General Scott Stewart argued for Watson. Several conservative justices pressed him with hypotheticals. Justice Thomas asked what counts as a “final choice” and whether handing a ballot to a neighbor would qualify as casting it. Justice Gorsuch posed a scenario in which a voter films themselves postmarking a ballot on Election Day and then has a relative deliver it three weeks later. Stewart repeatedly returned to the argument that the U.S. Postal Service is different because it is a “highly regulated government entity” with a duty to deliver. Under questioning from Justice Alito, Stewart conceded that under Mississippi’s reading there is essentially no federal statutory limit on how long after Election Day a state may count ballots cast by that day, though practical deadlines like the meeting of presidential electors would impose their own constraints.¹²

Liberal justices intervened to support Mississippi’s framing. Justice Jackson said the long tradition of states running their own elections “actually is pointed in your favor.” Justice Sotomayor argued that states have authority to designate any entity as an acceptable ballot recipient, “a notary, a military officer,” so long as the voter acts by Election Day, and said historical sources cited by the challengers were taken out of context.¹⁴¹⁵

SCOTUSblog’s analysis concluded that the justices “appeared ready to overturn state law allowing for late-arriving mail-in ballots.”¹¹

What a Ruling Against the Law Would Change

The impact would extend well beyond Mississippi. According to the National Conference of State Legislatures, 14 states plus the District of Columbia, Guam, Puerto Rico, and the U.S. Virgin Islands allow all absentee voters a post-Election-Day receipt window, with grace periods ranging from one day in Texas to 21 days in Washington. An additional 16 states provide grace periods specifically for military and overseas voters.¹⁶ The Brennan Center reported that in 2024, at least 750,000 ballots were postmarked by Election Day and counted within grace periods, not counting military and overseas ballots covered by separate grace-period rules.¹⁵

Amicus filers supporting the law warned about specific voter groups. A brief from the League of Women Voters, ACLU, Rural Coalition, American Association of People with Disabilities, and Disability Rights Mississippi argued that eliminating grace periods would disproportionately affect rural voters facing long mail delivery times, voters with disabilities, and older Americans, noting that nearly 25% of Mississippi residents are over 60.¹⁷⁹¹⁸

Not everyone views the disruption as large. Harvard Law professor Nicholas Stephanopoulos said the electoral stakes are “not enormously high” because most voters would adjust by mailing ballots earlier, and the number of ballots arriving after Election Day is relatively small.¹⁹

A decision would technically apply only to federal elections. In practice, analysts note that running two different receipt deadlines on the same ballot would be unworkable, so states would likely apply any new rule across the board.¹⁹ With federal midterms in November 2026, timing matters. The Court could make a ruling immediately effective or set a prospective date to let states update materials, retrain staff, and notify voters.¹⁸ Clement told the Court that states would have enough time to educate voters even if the decision came down this summer.¹⁰

Where the Case Stands

As of June 2026, Watson v. Republican National Committee is undecided. Argument was held March 23, 2026, and a decision is expected by the end of the Court’s term, likely late June or early July 2026. The district court has stayed further proceedings pending the ruling.⁷⁵

1
Mississippi Legislature. HB 1521, 2020 Regular Session
2
Courthouse News Service. Watson v. RNC Merits Brief
3
Mississippi Secretary of State. Absentee Voting Information
4
Mississippi Today. Republican Mail-In Ballot Lawsuit
5
Civil Rights Litigation Clearinghouse. Republican National Committee v. Wetzel
6
U.S. Court of Appeals for the Fifth Circuit. Republican National Committee v. Wetzel, 120 F.4th 200
7
SCOTUSblog. Watson v. Republican National Committee
8
U.S. Supreme Court. Watson v. RNC Petition and Appendix
9
Brennan Center for Justice. Watson v. Republican National Committee
10
CBS News. Supreme Court Mail Ballots Mississippi Law
11
SCOTUSblog. Court Appears Ready to Overturn State Law Allowing for Late-Arriving Mail-In Ballots
12
U.S. Supreme Court. Watson v. Republican National Committee Oral Argument Transcript
13
The White House. Preserving and Protecting the Integrity of American Elections
14
New York Post. Supreme Court Lawyer Nearly Stumped in Mississippi Mail-In Ballot Case
15
Brennan Center for Justice. Supreme Court Arguments Involved Misleading Claims About Mail Ballots
16
National Conference of State Legislatures. Receipt and Postmark Deadlines for Absentee Mail Ballots
17
U.S. Supreme Court. Watson v. Republican National Committee Amicus Brief
18
Bipartisan Policy Center. What Could the Supreme Court’s Decision in Watson v. RNC Mean for Mail Voting
19
Harvard Law School. Can Mail-In Ballots Be Counted After Election Day