Ohio’s new map of congressional districts is facing a constitutional challenge alleging it represents partisan gerrymandering by Republicans.

The lawsuit was filed in the Ohio Supreme Court by the National Democratic Redistricting Committee’s legal arm on behalf of a group of Ohio voters.

It challenges a map of U.S. House districts passed last week without Democratic support and signed into law Saturday by Republican governor Mike DeWine.

According to the suit, the map is “even more rigged than its predecessor.”

Ohio’s ruling Republicans assert that the map does not unduly favor either political party.