The US Court of Appeals for the Fifth Circuit on Friday invalidated a Mississippi election law that allowed mail-in and absentee election ballots as long as they were sent on or before Election Day. The ruling overturned the lower court’s decision that upheld the law.

The unanimous appeals court ruled that the Mississippi law was invalid because it violated the Electors Clause of the US Constitution, which sets Election Day as the same day throughout the United States. The court interpreted this day to mean the day when an election was “consummated,” meaning closed and ready to tabulate votes. The court stated: “Federal law requires voters to take timely steps to vote by Election Day. And federal law does not permit the State of Mississippi to extend the period for voting by one day, five days, or 100 days. The State’s contrary law is preempted.” The court viewed the impugned provision as effectively continuing the election beyond Election Day, in violation of federal law and the Elector’s Clause.

The court has jurisdiction over federal matters in the states of Texas, Louisiana, and Mississippi. This decision, which may be appealed to the US Supreme Court, is likely to be closely watched by courts in critical “swing states,” which are states where the election outcome is a toss-up, as well as the 21 states which have laws similar to the now invalid Mississippi law. If these laws are challenged, the court’s ruling would be a persuasive precedent in those challenges.

The US States are involved in the administration of elections through the Elections Clause, located in section 4 of the US Constitution, which by default gives Congress the power to regulate national elections. However, if there is an absence of federal law regulating a particular aspect of an election, the Elections Clause imposes a duty on states to organize the remaining details of federal elections, including the “time, place and manner of electing Representatives and Senators.” The Constitution’s Electors Clause states that “[election] day shall be the same throughout the United States.”

Given the rise in legal challenges and political controversies surrounding the 2024 US election, more issues are anticipated to arise both before and after the presidential election scheduled for November 5, 2024.