A bid by voting-rights activists in a heavily Trump-favoring state to stop a plot to rig the midterm elections took a big step this week — but Republicans are doing everything in their power to thwart it.

The fight is playing out in Missouri, where Republican state lawmakers and Gov. Mike Kehoe, following President Donald Trump's direction, passed a mid-decade partisan gerrymander that eliminates the Kansas City district held for years by Democratic Rep. Emanuel Cleaver.

However, unlike in Texas, where Republicans pushed a similar redraw, there is a process in Missouri to block such a map from taking effect. A group known as People Not Politicians has started a signature drive to qualify a ballot referendum that would let voters decide whether or not to adopt the new map.

If that referendum gathers enough signatures to qualify, 5 percent of the registered voters in 6 out of 8 congressional districts by Dec. 11, the map would automatically be suspended until voters decide on it.

On Wednesday, Missouri's Republican Secretary of State Denny Hoskins approved the signature petition, a major step that lets it move forward — but with a massive caveat. Hoskins declared all the signatures already gathered by People Not Politicians are invalid, and gathering must start over from zero. Any signatures turned in from before today, he warned, would be treated as a "misdemeanor election offense."

Meanwhile, according to Democracy Docket, Missouri Republicans, including Hoskins and Attorney General Catherine Hanaway, have filed a lawsuit in federal court seeking to block the referendum altogether as an invalid delegation of power away from the state legislature. Meanwhile, a lawsuit is also underway against the Missouri gerrymander itself.

All of this is unfolding as the Supreme Court takes on a case that could determine the future of Section 2 of the Voting Rights Act, the provision that prohibits discrimination against minority voters in the electoral process, including redistricting.