The Missouri Supreme Court upheld a new Republican-drawn congressional map on Tuesday, ruling that state law does not explicitly prohibit lawmakers from conducting mid-decade redistricting.

The map, which Missouri’s Republican governor signed into law last year, is designed to net the GOP a House seat in the 2026 midterm elections. Typically, states redraw their district lines every 10 years after a new census.

“The obligation to legislate congressional districts once a decade does not limit the General Assembly’s power to redistrict more frequently than once a decade. Simply put, ‘when’ does not mean ‘only when,'” Judge Zel M. Fischer wrote in the majority opinion, which was signed by four judges. Three other dissented.

It’s a win for President Donald Trump, who called on Republican-controlled states last year to redraw their congressional maps ahead of the midterms, where the GOP faces a tough battle to maintain control of the House. His calls triggered a national redistricting arms race between with both parties, with six states enacting new maps in 2025.

The fight is ongoing, with voters in Virginia set to weigh in on a Democratic-drawn map next month as Republican lawmakers in Florida are preparing for special special legislative session on redistricting.

Missouri’s new map aims to help Republicans unseat Democratic Rep. Emanuel Cleaver by moving parts of Kansas City into two more rural and Republican-leaning districts nearby. Six Republicans have filed to run for the newly drawn seat ahead of the August primary.

But opponents of the map are still hoping to block it through a voter referendum. While advocates say they have enough signatures to qualify their measure for the ballot, Republican Secretary of State Denny Hoskins, who supports the redrawn map, has not yet certified it.

The advocacy group People Not Politicians has sued to try to put the map on hold while that referendum is decided.

The NAACP has also appealed a separate lawsuit that challenges the map’s validity to the Missouri Supreme Court after losing their case at trial court last month.