The U.S. Supreme Court on Sept. 25 ruled against Republicans seeking to use Missouri’s 2025 congressional map in the Nov. 3 midterm elections, the same map lines that were used in the Aug. 4 primaries.

The nation’s highest court allowed a 2022 map, which gave Republicans a 6–2 edge over Democrats, to take effect. The 2025 map gave Republicans a 7–1 advantage.

The court issued an unsigned, five-page opinion in People Not Politicians v. Onder. No justices dissented.

“In short, as a matter of state law, the 2022 map—not the 2025 map—must be used in the 2026 congressional election,” the court said.

In recent weeks, the nation’s highest court issued two rulings against the 2025 map.

On Sept. 3, the Missouri Supreme Court ruled unanimously that the state must use the 2022 map for the November elections. County clerks have already begun sending military and overseas ballots using the 2022 map.

The U.S. Court of Appeals for the Eighth Circuit reinstated the 2025 map on Sept. 21, ruling that using a congressional district map in the November general elections that is different from the one used in the August primary elections would violate the U.S. Constitution.

Judge Stephen Clark of the U.S. District Court for the Eastern District of Missouri had issued a temporary restraining order barring Missouri Secretary of State Denny Hoskins from using any congressional map other than the one the Legislature approved in 2025. On Sept. 21, a three-judge Eighth Circuit panel affirmed Clark, ordering him to enter a permanent injunction blocking Hoskins from using any congressional map other than the 2025 map.

The panel administratively stayed that injunction until 5 p.m. Central Time on Sept. 28 to give the other side the opportunity to seek U.S. Supreme Court review. At the time that the administrative stay was issued, a Sept. 10 U.S. Supreme Court stay had blocked Clark’s original temporary restraining order.

Advocacy group People Not Politicians, which opposes the 2025 map and wants a referendum on it, submitted an emergency motion to the U.S. Supreme Court late on Sept. 22.

The group asked the U.S. Supreme Court to block the Eighth Circuit ruling, arguing that its Sept. 10 stay “precludes enforcement of the replacement injunction—or any additional federal court injunctions contrary to the stay order—so long as that stay remains in effect.”

In the high court’s new opinion, the justices summed up the legal theory argued by the federal plaintiffs—Rep. Bob Onder (R-Mo.), Republican congressional nominee Rick Brattin, and two Republican voters.

Their argument was that three parts of the U.S. Constitution—Article I, Section 2, which establishes the fundamental rules governing the U.S. House of Representatives; the elections clause; and the equal protection clause of the 14th Amendment—combine to forbid Missouri from using different congressional maps in the primary and general elections.

The justices did not reject Onder’s constitutional theory. Instead, they said they did not have to rule on it.

“On the merits, the Court’s precedents have not previously stated that Article I, Section 2 requires a state to use the primary election map in a general election, and given that the equities heavily favor staying this late-breaking intervention, it suffices that the merits are not entirely clearcut,” they said.

The justices did not hold that using different maps in the primary and general elections is constitutional; they held that the claim was too unsettled—and the election too far along—to justify an injunction.

The justices then turned to the Purcell principle, the doctrine that federal courts should not change a state’s election rules close to an election. The justices said the principle “applies with even greater force here” because the election “is not merely upcoming; it has already started.”

Local election officials told the courts it was “practically impossible to revert” to the 2025 map.

“At this late date, ordering reversion to the 2025 map in the midst of an ongoing election would usher in electoral chaos,” they said. “Purcell protects against such disorder.”

The Eighth Circuit argued the opposite: that Purcell favored the 2025 map because that was the map used in the August primary and that the Missouri Supreme Court’s Sept. 3 ruling constituted the last-minute disruption.

The justices said that federal courts’ interpretation of Purcell was incorrect because Purcell constrains federal courts, not states.

“Even though federal courts should not impose changes close to an election, States are free to decide for themselves whether last-minute changes to an election are in their best interests,” the justices said, quoting Allen v. Milligan (2023).

The Missouri Supreme Court, the justices said, was not the source of the late change. In opinions issued in May 2026—months before the primaries—the state high court had already said the 2025 map would not take effect unless voters approved it in a referendum, as long as the petition calling for it was legally sufficient.

“[Hoskins] was well aware that conducting the August primary election with the 2025 map carried significant risks,” the justices said.

“The Secretary nonetheless chose to proceed with the 2025 map for the primary.”