Supreme Court Case Could Rewrite Rules for Mail and Military Voting

On November 10, 2025, the U.S. Supreme Court announced that it will hear Watson v. Republican National Committee — a case that could have sweeping implications for mail and military voters across the country.

---

---

At issue is whether federal statutes defining “Election Day” for federal elections can preempt state election laws that allow election officials to count mail ballots postmarked by Election Day and received shortly thereafter. 

If the Court upholds the ruling currently in place, dozens of states may have to change laws that accept ballots postmarked by Election Day. For military and overseas voters — and for voters living in states with limited mail ballot return options — this grace period is crucial to ensuring all eligible voters’ ballots are counted.

The Case Originates in Mississippi, but Has National Implications.

The Mississippi Republican Party, the Republican National Committee, and two Mississippi voters are challenging a Mississippi law that allows election officials to count mail ballots postmarked by Election Day. Under Mississippi law, completed mail ballots are counted as long as they are postmarked on or before Election Day and received within five business days after the election. The Fifth Circuit Court of Appeals ruled that federal law establishing a “single Election Day” requires all ballots to be received — not just postmarked — by Election Day. The state of Mississippi appealed that decision to the U.S. Supreme Court, which will hear the case.

Parties will have several months to brief the case before the U.S. Supreme Court hears oral argument, which will likely occur in late winter or early spring 2026. The Court will likely issue its ruling before the end of its term in late June or early July. Depending on the ruling, this case could significantly change election law in numerous states across the country.

Military and Overseas Voters, Voters With Disabilities, and Senior Citizens Could Be Most Affected

Voters who rely on mail voting, such as military and overseas voters, voters with disabilities, and older voters, would face the most significant impacts if postmark deadlines are struck down. These voters, who already face challenges not experienced by a typical voter, would have to overcome even greater obstacles to ensure that their votes count.

In states that lack alternative mail ballot return options (such as drop boxes), grace periods are crucial to ensuring that all eligible voters’ ballots are counted. In Mississippi, for example, where the case originated, the legislature has banned drop boxes, meaning voters can only return ballots by mail or in person at their election office. 

Concerns about timely postal service, domestically and internationally, underscore the need for grace periods to ensure that ballots completed by voters on or before Election Day are not discarded solely because of delivery delays. In recent elections in Pennsylvania and North Carolina, thousands of valid ballots cast by U.S. citizens arrived at election offices just a few days after Election Day. These ballots, all postmarked on time, are enough to sway election outcomes in close races. 

Dozens of States May Have to Change Their Laws. 

This case could upend election law in dozens of states right before the 2026 midterms, creating chaos for local election officials and confusion for voters. 

• Sixteen states and D.C. currently allow mail ballots postmarked by Election Day to be counted if they arrive within a specified grace period for all mail voters.
• Twenty-nine states offer similar postmark deadlines and grace periods specifically for military and overseas voters.

If the Supreme Court rules that federal statutes preempt these state laws, then these states will likely need to change their laws to comply. Since the Court will issue its opinion in the middle of a federal election year, states may have to move quickly ahead of primary or general elections, creating confusion and chaos for voters and election officials alike. 

For more Supreme Court cases that could reshape how Americans vote and who is represented, see our latest analysis.