Missouri first to adopt fairness test against gerrymandering
JEFFERSON CITY, MO. >> The votes won’t be cast for another four years, yet Democrats already appear likely to gain seats in Missouri’s Republican-dominated Legislature in 2022.
The reason: a one-of-its kind redistricting initiative approved by voters in the recent midterm elections.
Missouri’s initiative marks a new frontier in a growing movement against partisan gerrymandering that has now notched ballotbox victories in eight states over the past decade.
Other states have created independent commissions and required bipartisan votes to redraw legislative and congressional districts. Missouri will be the first to rely on a new mathematical formula to try to engineer “partisan fairness” and “competitiveness” in its state legislative districts; the Legislature will continue drawing the state’s congressional districts.
An Associated Press analysis of the new Missouri formula shows it has the potential to end the Republicans’ supermajorities in the state House and state Senate and move the chambers closer to the more even partisan division that is often reflected in statewide races. But the size of the likely Democratic gains remains uncertain, partly because the formula has never been put to a test.
“Missouri’s engaged in an experiment,” said Sam Wang, director of the Princeton University Gerrymandering Project, which uses math to measure partisan advantages in redistricting.
“Democrats have a fighting chance in a way that they didn’t before,” Wang added. But “a lot of it depends on what they do with it.”
After the 2010 census, Republicans nationwide controlled more state legislatures and governor’s offices than Democrats. They used that power to draw legislative and congressional districts that benefited the GOP.
Since then, advocates have been trying to reform the system to eliminate or greatly reduce partisan gerrymandering, which has been used by both parties over the years to draw political boundaries in ways that give the dominant party a disproportionate hold on power. They have succeeded in making the process less partisan in a number of states, mostly through ballot initiatives approved by voters.
Nov. 6 was the latest example of the trend, when voters in Colorado, Michigan and Utah joined Missouri in approving new redistricting systems.
All states must redraw their congressional and state legislative districts after the 2020 census. Those new maps generally will kick in for the elections two years later. Although the criteria vary by state, most require districts to contain similar populations, keep communities together when possible and give minorities a chance to elect candidates of their choice.
The constitutional amendment approved by Missouri voters in November keeps those criteria. But it also requires a new nonpartisan state demographer to base state House and Senate districts on the votes cast in the previous three elections for president, governor and U.S. senator — races that are decided by voters statewide and are not affected by gerrymandering.
The districts must come as close as practical to achieving “partisan fairness” as measured by a formula called “the efficiency gap.”
That formula was created earlier this decade by Eric McGhee, a researcher at the nonpartisan Public Policy Institute of California, and University of Chicago law professor Nick Stephanopoulos. It compares the statewide share of the vote a party receives with the statewide percentage of seats it wins, taking into account a common political expectation: For each 1 percentage point gain in its statewide vote share, a party normally increases its seat share by 2 percentage points.