Redistricting for Proportionality

TL;DR

This paper explores the feasibility of designing single-member district systems that achieve proportional representation, analyzing a proposed reform to improve fairness and legal robustness in U.S. redistricting.

Contribution

It introduces a targeted approach to redistricting that aims to align district outcomes with proportionality norms, using the 'Freedom to Vote Test' as a case study.

Findings

Applying the test improves proportionality in key states

The approach performs well in legal challenges

An exception mechanism handles difficult cases

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 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.