Public Choice Principles of Redistricting

This paper uses fundamental principles of public choice, mainly the median voter theorem, to develop a simple theory of redistricting. The focus is on how closely policy outcomes correspond to majority rule. The main results are: (1) Potential policy bias in favor of nonmajority groups is structurally linked to the number of legislative seats and the population, and the structure of most states puts them very close to the theoretically maximum bias. (2) Random districting, which might seem like the essence of neutrality, does not eliminate policy bias on average. (3) Traditional principles of compact, contiguous districts that respect existing political boundaries, stressed in the Supreme Court’s Shaw v. Reno decision, minimize the chance of nonmajoritarian outcomes. Our analysis also offers a gerrymandering explanation for the positive relation between seats and spending that is usually taken as support for the “Law of 1/n.”