On Monday, November 10, 2025, the U.S. Supreme Court agreed to hear a case that could reshape how mail-in ballots are counted across the country, thrusting the issue of late-arriving ballots into the national spotlight just ahead of the pivotal 2026 midterm elections. The case, Watson v. Republican National Committee, stems from a challenge to a Mississippi law that allows mail-in ballots received up to five days after Election Day to be counted, provided they are postmarked on or before that day.
At first glance, the case might seem like a technical question about deadlines. But the stakes, as officials and advocates on all sides point out, are anything but small. In fact, the outcome could upend mail-in voting rules in dozens of states, potentially affecting millions of voters—including military personnel and expatriates—who rely on the flexibility of postal voting. As The Week notes, "a decision overturning Mississippi’s law could upend mail-in ballot rules in dozens of states in time to roil the 2026 midterm elections."
Currently, more than two dozen states—including major battlegrounds like Nevada, Colorado, Oregon, Utah, and Washington—accept mail-in ballots that arrive after Election Day as long as they are postmarked by the deadline. According to the National Conference of State Legislatures, Mississippi is one of 18 states plus the District of Columbia with such provisions. An additional 14 states allow late-arriving ballots from specific groups, such as overseas military members and their families, as AP and The Nevada Independent report.
The controversy began when a panel of the 5th U.S. Circuit Court of Appeals, all nominated by President Donald Trump, ruled that Mississippi’s law allowing late-arriving ballots violated federal law. The panel argued that Congress had established a "singular" Election Day for federal offices, meaning ballots must be both cast and received by that date. Judge Andrew Oldham, writing for the panel, stated, "Congress established a 'singular' Election Day for members of Congress and presidential electors, 'by which ballots must be both cast by voters and received by state officials.'" Judges James Ho and Stuart Kyle Duncan joined Oldham’s opinion, which invalidated Mississippi’s law and reversed a lower court decision that had found no conflict between state and federal law.
Mississippi Attorney General Lynn Fitch, a Republican, quickly appealed to the Supreme Court, warning that the appellate decision "would have destabilizing nationwide ramifications" if left in place. In her brief, Fitch wrote, "The stakes are high: ballots cast by—but received after—Election Day can swing close races and change the course of the country." According to AP, Fitch argued that upholding the 5th Circuit’s ruling would require scrapping election laws in most states and risk chaos in upcoming federal elections.
The political backdrop to this legal fight is as charged as ever. President Donald Trump, who has long claimed that late-arriving ballots and lengthy vote counts undermine public confidence in elections, signed an executive order in March 2025 requiring all votes to be both cast and received by Election Day. This order, however, faces its own court challenges, and several states, including Nevada, have resisted efforts to tighten deadlines. The Nevada Independent points out that in the state’s 2024 election, of roughly 587,000 mail-in ballots counted in Clark and Washoe counties, only 3.8%—about 11,875 votes—were received after Election Day but postmarked on time.
Efforts to restrict late-arriving ballots are not limited to Mississippi. Republican-led states such as Kansas and North Dakota have moved to stop counting these ballots, and Ohio’s state Senate has passed legislation requiring all ballots to be received by Election Day. In Nevada, Governor Joe Lombardo has echoed Trump’s call to end universal mail-in voting, stating in his 2025 State of the State address that all ballots should be received by the time polls close. However, no such bill passed in the state’s Democrat-controlled Legislature in 2025.
On the other side, Democratic officials and voting rights advocates argue that grace periods for late-arriving ballots are essential to ensure every eligible vote is counted, especially for voters facing mail delays outside their control. Washington Attorney General Nick Brown, a Democrat, joined other state attorneys general in filing a friend-of-the-court brief urging the Supreme Court to side with Mississippi and preserve the grace period. They noted that the 5th Circuit’s decision "jeopardizes the ability of military service members and their families stationed abroad to have their timely cast ballots counted," as The Seattle Times reported.
Washington, which conducts its elections almost entirely by mail, allows ballots to be counted up to 21 days after Election Day if they are postmarked on time. In the state’s most recent elections, nearly 120,000 valid ballots arrived after Election Day but were still counted. The state’s Secretary of State, Steve Hobbs, expressed support for the Supreme Court taking up the case, saying, "We view this as an important opportunity for the Court to provide clarity on the authority of states to accept ballots received after Election Day, provided they are mailed by Election Day and meet all other requirements established in state law."
The Republican National Committee and Libertarian Party of Mississippi, who led the challenge to Mississippi’s law, argue that a uniform national deadline is necessary to ensure fairness and public trust. They claim that allowing ballots to arrive after Election Day deprives voters of a clear, nationwide standard and can lead to confusion or allegations of impropriety in close races. As the appellate panel put it, the absence of a strict deadline "puts all voters on the same footing," a principle they believe is essential to election integrity.
Federal courts have been split on the issue. In Nevada, a federal judge dismissed a challenge to the state’s law allowing late-arriving ballots, but that decision is currently under appeal. The Supreme Court is also considering whether to revive a lawsuit by Rep. Mike Bost (R-Ill.), backed by the Trump administration, which challenges Illinois’ ballot receipt law. That case, however, focuses on whether the congressman has legal standing to sue rather than the underlying deadline issue.
The Supreme Court is expected to hear arguments in the Mississippi case in late winter or early spring of 2026, with a final decision likely by late June—just in time to set the rules for the midterm elections. As The New York Times observes, the ruling could be a "potential blockbuster" with the power to reshape the landscape for mail-in voting across the country.
With both sides warning of chaos and disenfranchisement if their opponents prevail, the coming months promise heated debate, legal wrangling, and, for millions of Americans, uncertainty about how their votes will be counted. As the nation awaits the Supreme Court’s decision, the future of mail-in voting—and, perhaps, the outcome of future elections—hangs in the balance.
