Sixteen plaintiffs, supported by the National Redistricting Foundation, sued the US state of Missouri on Sunday, alleging that a new law redistricting federal congressional seats violates the state’s constitution.

Missouri Governor Mike Kehoe signed the new legislation, enthusiastically backed by President Donald Trump, into law that same day. It aims to redistrict a Democrat-held federal congressional seat for Kansas City and turn it into a Republican-leaning seat. Missouri is one of several states around the US looking to change the landscape of the US House of Representatives ahead of the 2026 midterm elections.

NRF executive director Marina Jenkins said in a statement that the law does not reflect that of Missouri residents but rather that of conservative politicians in both Missouri and Washington DC. “The new gerrymander undermines representation for rural and urban communities by forcing these very different communities into districts that stretch hundreds of miles across the state,” Jenkins said. “This is a clear-cut case, and we are confident Missourians will see justice delivered.”

Kehoe touted the passage of the new map, called the “Missouri First Map,” saying he was proud to sign the legislation into law ahead of the 2026 midterm election.

“Missourians are more alike than we are different, and our values, across both sides of the aisle, are closer to each other than those of the congressional representation of states like New York, California, and Illinois,” Kehoe said. “We believe this map best represents Missourians, and I appreciate the support and efforts of state legislators, our congressional delegation, and President Trump in getting this map to my desk.”

The new law affects Missouri’s Fifth congressional district, which Democratic US Representative Emanuel Cleaver has represented since 2005. Cleaver had called the new map an “unconstitutional gerrymander.”

The NRF argues the new legislation violates the Missouri’s Constitution, Article III, Section 45, by redistricting before the next scheduled United States Census that would have to show the districts should change. There was also no court order requiring the state to redraw its congressional districts. The last new congressional map adopted in 2022 by Missouri’s Legislature followed the 2020 census.

This is the latest redistricting effort ahead of the 2026 midterm elections. Texas passed a similar initiative in August, as has California, which will place its proposed new map on the state’s election ballot this fall.