Optimal Districting with Endogenous Party Platforms

Abstract

This paper proposes a theory of socially optimal districting in a legislative-election model with endogenous party platforms. We generalize the model of Coate and Knight (2007), allowing parties to strategically condition their platforms on the districting. The socially optimal districting re ects the ideological leaning of the population, so that parties internalize voters' preferences in their policy platforms. The optimal seat-vote curve is unbiased when voters are risk-neutral, and -contrary to previous findings-biased against the largest partisan group when voters are risk-averse. The model is then calibrated by an econometric analysis of the elections of U.S. State legislators during the 1990s.