Research shows redistricting commissions reduce gerrymandering
To avoid partisan gerrymandering, a number of states removed redistricting from the legislature and found another way to draw their maps. In 10 states, redistricting commissions draw congressional districts; in 12 states, commissions draw state legislative maps.
For all, the goal is to make constituencies fairer, and also more competitive (in other words, which are not so tilted one way or the other that they always elect whoever wins the primary d one party or another). In general, commissions draw fairer maps, according to the research, although the evidence is more mixed on whether they improve political competition.
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Committees drew fairer 2022 maps than legislatures
So how far have commissions fared in the current round of redistricting? In recent research, we found that commissions achieved both goals: they drew fairer legislative maps of Congress and states than state legislatures, and they drew fewer districts that were a slam dunk for one party or state. ‘other.
Here’s how we know. We looked at all redistricting plans for the US House and state legislatures using a measure called the “efficiency gap.” The efficiency gap determines whether a party maximizes its share of seats by efficiently distributing its voters across many constituencies while consolidating the other party’s voters into a few constituencies that the party is guaranteed to win. When the efficiency gap is large, it is a sign that a political party has rigged the card.
We then looked at how the efficiency gap varied depending on who drew the map, focusing on states with three or more congressional districts where we could more easily measure partisan bias in their district map.
Not surprisingly, we found that plans made by Democrats were biased in favor of Democratic candidates, while plans made by Republicans were biased in favor of Republican candidates. In fact, supporters almost always drew plans that gave their party an advantage when translating votes into seats. Plans drawn by Democrats tended to have a pro-Democrat effectiveness gap of about 10%, while plans drawn by Republicans had a pro-Republican effectiveness gap of 10%. In contrast, we found that plans made by commissions, divided governments, or courts were much fairer – with average efficiency gaps that were indistinguishable from zero, meaning that districts across the state gave no advantage to one party.
State judges — especially Republican judges — tend to favor their own party’s district cards
We found the same pattern when we compared the new maps to previous maps from 2011 and thousands of nonpartisan computer-drawn maps from Project ALARM, which don’t take politics into account. No matter how we measured it, we found that courts and commissions created maps that were less biased than maps drawn by partisans.
Commissions also attracted more competitive districts
Redistricting commissions also attracted more competitive districts. For congressional plans, they drew competitive districts about 10 percentage points more often than those drawn by partisan legislatures. And commissions drew competitive state legislative seats about 2.5 percentage points more often than politicians did in their maps.
Will more states adopt redistricting commissions?
Of course, politicians are unlikely to adopt commissions on their own. They prefer to control the process themselves and give the advantage to their party.
But voters could take that into their own hands, passing ballot initiatives requiring redistricting commissions, as they did in Arizona, Colorado, California, Michigan and Virginia. Oregon could vote on the issue in 2024, and voters in Arkansas, Florida and Massachusetts also have the power to put redistricting commissions on their ballots. The Ohio chapters of Common Cause and the League of Women Voters are discussing a ballot initiative that would transform its politician-led redistricting commission into an independent, nonpartisan commission.
New Gerrymandered Maps Might Hurt Democrats Less Than You Think
However, this mandate, the Supreme Court will hear Moore v. Harperin which the North Carolina State Legislature challenges the ability of the State Supreme Court to review the legality of Congressional maps and other rules for federal elections. At issue is the so-called “independent state legislature theory,” which holds that the Constitution explicitly gives state legislatures the power to designate congressional districts. If it sides with the North Carolina legislature, the Supreme Court could find most state precinct commissions for congressional elections unconstitutional.
Removing redistricting commissions would almost certainly lead to fewer fair and competitive elections, according to our research. If fairness and competition are the goals, the country needs more redistribution commissions, not less.
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Christopher Warshaw is an associate professor of political science at George Washington University and co-author of Dynamic Democracy: Public Opinion, Elections, and Policymaking in American States.
Eric McGhee is a Senior Fellow at the Public Policy Institute of California.
Michael Migursky is the executive director of PlanScore.