The U.S. Supreme Court will hear arguments Monday on a Mississippi case that challenges whether ballots received after Election Day can be counted in federal elections, a decision that could significantly impact Alaska and other states with similar mail-in voting practices.

The case, brought by the Republican National Committee and others, argues that grace periods for late-arriving ballots improperly extend elections for federal office. Mississippi defends its law by stating that no voting occurs after Election Day, only the delivery and counting of already completed ballots.

Alaska currently counts ballots if they are postmarked by Election Day and received within 10 days, or 15 days for overseas voters in general elections. The state is one of 14 that allow all mailed ballots postmarked by Election Day to arrive days or weeks later and be counted, with an additional 15 states providing grace periods for military and overseas ballots.

Alaska's geography and logistics make the case particularly significant for the state. Many of Alaska's rural communities, including Alaska Native villages, rely on air service for mail delivery and basic supplies. About 50,000 Alaskans voted by mail in the 2024 presidential election. In the 2022 general election, between 55% and 78% of absentee ballots from certain House districts arrived after Election Day, and statewide about 20% of all absentee ballots were received after Election Day.

Senator Lisa Murkowski, a Republican, said Alaska could face more detrimental impacts than any other state if the Supreme Court rules against late-arriving ballots. Alaska Attorney General Stephen Cox filed a brief outlining the state's geographic and logistical challenges, including connectivity issues that sometimes prevent poll workers from relaying results by phone on election night.

Advocates warn that requiring ballots to be received by Election Day could disproportionately affect Alaska Native voters, as limited postal service in rural areas means some ballots might not be postmarked until they reach major cities like Anchorage or Juneau. The case comes as the Senate debates legislation requiring proof-of-citizenship to register to vote and photo ID to cast ballots.