The U.S. Supreme Court has blocked a Republican-drawn congressional redistricting map in Missouri for the third time, ordering the state to use the same district boundaries that were in place during the 2022 and 2024 elections.
The ruling came as voting began in the midterm elections and as election officials had already started mailing absentee ballots using the older district lines.
The court warned that switching maps at this stage would cause "electoral chaos." The decision requires Missouri to revert to its previous congressional districts, even though a different map had been used in the state's primary elections last month.
The redistricting plan had been passed by Missouri lawmakers at the behest of President Trump. It was part of a broader national strategy to draw more Republican-leaning congressional seats and protect the party's majority in the U.S. House. Republicans currently hold only a narrow advantage in the chamber.
The new map was also designed in a way that could have affected Democratic Congressman Emanuel Cleaver's district by increasing the number of Republican voters within it.
The dispute triggered weeks of conflicting rulings in both state and federal courts. Opponents of the new map gathered enough citizen signatures to place the redistricting plan on the November ballot, subjecting it to voter approval.
The Missouri Supreme Court ruled earlier this month that the ballot petition meant the 2025 Republican-backed map had never legally gone into effect — even though it had been used in the August 4 primary elections. The state court blamed Republican Secretary of State Denny Hoskins for proceeding with the new map in the primaries before voters had approved it.
The U.S. Supreme Court's ruling on Friday backed that position, noting that the state court had said as early as May — before the primary — that the Republican map would require voter approval before it could be used.
The U.S. Supreme Court had previously declined on September 10 to intervene in the state court's ruling but allowed the legal challenge to continue.
Republicans simultaneously pursued the case in federal court, winning backing for their map from a federal judge and, last week, from a federal appeals court. That outcome sent the matter back to the U.S. Supreme Court, which ruled against Republican lawmakers on Friday.
Republicans argued their map should stand because more than one million Missourians had already cast primary votes using it. Opponents countered that voters had never approved the map and accused Republican officials of deliberately prolonging the process in an attempt to force the new boundaries into effect.
