The Missouri House on Monday sent the Senate a proposed constitutional amendment that would erase parts of Amendment 1 that voters adopted last November.
The measure passed Monday by a vote of 104-49; eight Republicans voted in opposition.
Supporters of that Amendment 1, also known as "Clean Missouri," wasted little time in urging people to contact their senators and ask them to oppose the resolutions.
"This new constitutional amendment would not only undo the voters' mandate for fair maps and fair redistricting," Clean Missouri Director Sean Soendker Nicholson wrote in an email, "it would make our redistricting process more political than it was before the landslide passage of Amendment 1."
And Lauren Gepford, executive director of the Missouri Democratic Party, said in a separate statement: "This is yet another example of the Republican majority in the legislature asserting that they know better than the people of Missouri."
In November, more than 1.4 million Missourians — or more than 62 percent of those who cast ballots — approved the "Clean Missouri" plan.
It made several changes to Missouri's Constitution, including:
The proposed new amendment mainly targets the redistricting changes.
Before Amendment 1, Missouri's Constitution required those districts to be "composed of contiguous territory as compact as may be," with an extra requirement that state Senate districts don't cross county lines except in areas where the population is too large to be in one district.
Amendment 1 added a criteria of partisan fairness and competitiveness, and an objective to keep cities within the same district unless they were too large for one district.
Nicholson said Monday: "Lobbyists and political appointees could split communities in the name of 'compactness.'"
The proposed new amendment would require districts to be composed of contiguous territory and as compact as possible, and that they approximate squares, rectangles or hexagons to the extent permitted by natural or political boundaries.
The proposed new amendment also would create new redistricting commissions for the House and Senate, with members appointed by the governor based on recommendations from the congressional committees of the two political parties with the most votes in the previous election.
That mirrors the process the state has used for years, but with smaller committees.
Nichols said: "Political appointees could rig maps to advance their own interests."
If the Senate also passes the measure before May 17, it would be placed on a statewide ballot next year, and would have to be approved by a simple majority of the voters before it could go into effect.
Gepford said: "Members of the Missouri Senate should tread carefully because Clean Missouri passed in every single Senate district last November."