The Supreme Court’s conservative majority appeared ready to overturn a Mississippi law that allows mail-in ballots to be counted as long as they are postmarked by, and then received within five business days of, Election Day after just over two hours of oral argument in Watson v. Republican National Committee on Monday.
Because more than a dozen states have similar laws, the court’s ruling – which is expected by late June or early July – could have significant implications for federal elections, beginning as soon as November . The lawsuit against Mississippi’s practice was brought by the Republican National Committee in 2024 and puts into jeopardy the mail ballot deadlines of several other states. Thirteen other states and the District of Columbia also set mail ballot receipt deadlines after Election Day .
The case centers on Mississippi’s law, passed in 2020 in response to the COVID-19 pandemic , which allows officials to count mail-in ballots received up to five business days after Election Day if they were postmarked by that day . The Republican National Committee, the Mississippi Republican Party, a Mississippi voter, and a county election official went to court to challenge the law, arguing that Mississippi’s law clashed with a federal law, enacted by Congress in 1845, that establishes the Tuesday after the first Monday in November as “election day” .
During oral arguments, several conservative justices, including Justice Amy Coney Barrett, often seen as a possible swing voter, latched on to a line of questioning put forward by Justice Clarence Thomas implying that permitting Mississippi’s law would also allow a voter have his ballot counted if he simply handed his ballots to his neighbor by Election Day. Justice Brett Kavanaugh, another sometimes-swing vote on the court, also leaned into the arguments against grace periods for mail ballots .
Justice Samuel Alito expressed broader concerns about election timing. “We don’t have Election Day anymore,” said Justice Samuel Alito. “We have election month, or we have election months” . Kavanaugh raised the possibility that those regulations erode confidence in elections if late-arriving ballots determine the outcome and pointed to the fact that the practice expanded greatly during the Covid-19 pandemic, suggesting that undermined the idea that it has a long-established history .
U.S. Solicitor General D. John Sauer argued on behalf of the Trump administration, which filed a “friend of the court” brief supporting the challengers. Sauer told the court that “Mississippi’s theory of election is so general and permissive that it would authorize statutes that Congress could not possibly have approved in the 19th century” .
The court’s liberal justices pushed back strongly. Justice Sonia Sotomayor pointed out that “nothing in federal law” explicitly prohibits Mississippi’s grace period and reminded the court the law is “very consistent with what has happened for over a hundred years” .
Justice Ketanji Brown Jackson pushed back on the idea that federal law locks states into a single, rigid understanding of Election Day, cautioning that the legal theory advanced by the Republican National Committee “imperils a lot of different things, not just post-Election Day ballot deadlines” .
Mississippi Solicitor General Scott Stewart defended the state’s position, arguing “This is ultimately a federalism case. The question is whether, as I think Justice Jackson put it, did Congress in 1845 block states from adopting a practice that no one had reason to consider at the time” .
The stakes extend far beyond Mississippi. Fourteen states, Washington, D.C., and three U.S. territories allow grace periods for mail-in ballots that are postmarked by Election Day, though the exact lengths of those windows vary. Additionally, 29 states allow extra time for mail-in ballots cast by service members and Americans abroad .
Election officials across the country warned that a switch could lead to mass confusion in this year’s election — and higher costs. A group of local election officials told the justices that 13 other states, and Washington, DC, have similar ballot laws on the books and that changing their procedures to comply with the court’s ruling could be a tricky task. “Eliminating post-election ballot receipt deadlines would affect nearly every aspect of the preparation for and administration of the general election in these states in 2026, just months before it is set to occur,” the group said in an amicus brief .
The case has already prompted legislative action. On March 19, Mississippi Gov. Tate Reeves (R) signed HB 908 into law. If the U.S. Supreme Court overturns Mississippi’s mail-in ballot law, HB 908 would require mail-in ballots to be received the day before an election (rather than up to five days after an election if they were postmarked on or before the election) .
The timing concerns extend to implementation. When Justice Brett Kavanaugh asked if the court were to rule for the challengers in a decision issued in June, would it be too late to implement that decision for the 2026 elections, attorney Paul Clement responded that it would not be. Under