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Briefs Showing That Geography Does Not Account for the Partisan Bias in Wisconsin’s Map

To help court-watchers sort through more than one thousand pages of amicus briefs in Gill v. Whitford, the Brennan Center has prepared an annotated guide breaking down each brief’s most important arguments.

September 19, 2017

Brief of Political Geography Scholars in Support of Appellees

Summary: This brief, filed by several experts in political geography and statistical analysis, describes modeling techniques that can be used to assess the extent to which the relative distributions of partisans throughout a given state accounts for any observed partisan bias in that state’s electoral maps. Applying these techniques to Wisconsin’s state assembly map, the scholars tell the Court that the partisan asymmetry in Wisconsin was the product of intentional partisan manipulation, not a result of any geographic clustering of partisans. Professor Richard H. Pildes of the New York University School of Law and the law firm Sidley Austin are co-counsel for this brief.

Brief of Robin Best, Shawn J. Donahue, Jonathan Krasno, Daniel B. Magleby and Michael D. McDonald in Support of Appellees

Summary: This brief, filed by social scientists specializing in the quantitative study of American electoral systems, sets forth key findings from their analyses of Wisconsin’s state assembly map. Based on an analysis of 10,000 maps generated through a simulated mapping application, the authors determined that Wisconsin’s enacted map disadvantages Democratic voters substantially beyond any level explainable by the state’s residential geography. The law firm McLaughlin & Stern is counsel for this brief.

Brief for Eric S. Lander in Support of Appellees

Summary: This brief, filed by Professor Eric S. Lander, explains how courts can identify extreme gerrymanders by comparing partisan outcomes under actual maps to the expected outcomes produced by a range of simulated maps. The law firm Smith Duggan Buell & Rufo is counsel for this brief.