Redistricting for Proportionality

Abstract

American democracy is currently heavily reliant on plurality in single-member districts, or PSMD, as a system of election. But public perceptions of fairness are often keyed to partisan proportionality, or the degree of congruence between each party’s share of the vote and its share of representation. PSMD has not tended to secure proportional outcomes historically, partially due to gerrymandering, where line-drawers intentionally extract more advantage for their side. But it is now increasingly clear that even blind PSMD is frequently disproportional, and in unpredictable ways that depend on local political geography. In this paper we consider whether it is feasible to bring PSMD into alignment with a proportionality norm by targeting proportional outcomes in the design and selection of districts. We do this mainly through a close examination of the “Freedom to Vote Test,” a redistricting reform proposed in draft legislation in 2021. We find that applying the test with a proportionality target makes for sound policy: it performs well in legal battleground states and has a workable exception to handle edge cases where proportionality is out of reach.

Geometry, inference, complexity, and democracy

“…Pegden was subsequently appointed by Governor Tom Wolf to serve on the Pennsylvania Redistricting Reform Commission, along with the more traditional group of elected officials and community leaders you might expect to find on a political panel like this. Wolf also enlisted Moon Duchin to help evaluate replacement districting plans [11]. In North Carolina, a state court similarly found that state legislative districts drawn by the majority in the state legislature violated both the Free Elections Clause and the Equal Protection Clause of the North Carolina Constitution.…”

A Partisan Solution to Partisan Gerrymandering: The Define–Combine Procedure

“…Parties and candidates need not account for uncertainty in future elections or shifting voter preferences over time with these assumptions.4 In practice, there will be a large number of maps in M (even in some of the simple examples here, there may be millions or billions of legal maps). Thus, M does not have to be the complete set of feasible maps, but rather a subset of all feasible maps in which Ui varies.5 Research on redistricting in URP states, such as Florida, Maryland, Wisconsin, and Pennsylvania, finds chosen plans to be extreme outliers in the distribution of possible maps(Chen and Rodden 2015;Cho and Liu 2016;Duchin 2018).6 Valid districts are contiguous and have equal population. Strict constraints on compactness, geographic splits, or other restrictions are not necessary, but such limitations could be included.…”