A group of Democratic voters in Wisconsin filed suit against the state’s elections commission on Friday, asking a federal court in Madison to declare the state’s current legislative and congressional districts unconstitutional for use in imminent redistricting efforts.

The lawsuit, which came less than a day after the Census Bureau released its detailed decennial population data to states, argued in particular that Wisconsin’s current districts are “unconstitutionally malapportioned” and based on old data. It further asked the U.S. District Court for the Western District of Wisconsin to intervene with a plan of its own in the event that Democratic Gov. Tony Evers and the Republican-led state legislature fail to reach a deal on a redistricting plan.