Automated Redistricting and Partisan Strategic Interaction: Lessons from Mexico

• In Event: Redistricting and Electoral Administration

Abstract

In the U.S. redistricting is deeply politicized and often synonymous with gerrymandering —the manipulation of boundaries to promote the goals of parties, incumbents, and racial groups. In contrast, Mexico’s independent electoral management board has implemented a federal redistricting process since 1996 that features plans created according to non-partisan criteria using an automated algorithm. Although observers often describe Mexico’s process as transparent and objective, the political parties are permitted to make private counter-proposals to the algorithmically generated plans. The discrepancy between a purportedly open process and the closed partisan bargaining interaction raises a broad set of questions about the objectivity of the process, its transparency, and the conduct of the parties. How objective is this process on the whole? How well does the algorithm achieve the desired goals as defined, and how robust are the results to small changes in the measurement of the goals? Does the formulation of criteria, and/or the rules of the proposal process advantage specific parties? How does the closed-door partisan bargaining affect the drawing of electoral districts? Did parties behave strategically -- and what effect did party action have on the final outcomes? Is there evidence the rules were contested, interpreted uniformly, or subverted? Were specific parties able to use this process to their advantage? How much did party proposals affect potential indigenous representation? We address these questions by utilizing a novel dataset that has remained unavailable outside the Mexican bureaucracy. This dataset comprises the entire set of plans proposed by political parties during the 2013 and the 2017 redistricting processes. Our analysis offers a unique insight into the internal workings of an independent election board and the ways in which parties strategically interact to secure their electoral interest. Our work provides guidance for those aiming to delegate the redistricting process to independent commissions while still including political parties in the deliberation process.

Authors

• Alejandro Trelles, Brandeis University

• Eric Magar, Instituto Tecnologico Autonomo de Mexico

• Michael P. McDonald, University of Florida

• Micah Altman