Cutting Through the Thicket: Redistricting Simulations and the Detection of Partisan Gerrymanders

Abstract Social scientists have made progress in providing the courts with useful measures of partisan asymmetry in the transformation of votes to seats, but have thus far left a larger question unanswered: how can partisan gerrymandering be distinguished from a state legislature's acceptable efforts to apply traditional districting criteria, keep communities of interest together, and facilitate the representation of minorities? This article demonstrates how a straightforward redistricting algorithm can be used to generate a benchmark against which to contrast a plan that has been called into constitutional question, thus laying bare any partisan advantage that cannot be attributed to legitimate legislative objectives. We use the controversial 2012 Florida Congressional map to show how our approach can be used to demonstrate an unconstitutional gerrymander.