Skip Navigation

Briefs Explaining How Social Science Can Help Detect Partisan Gerrymanders

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 Bernard Grofman and Ronald Keith Gaddie in Support of Neither Party

Summary: This brief, filed by two redistricting experts (including one who helped develop the map at issue in Whitford), advises the Court that any workable standard for detecting unconstitutional partisan gerrymandering should include three elements—partisan asymmetry, lack of responsiveness, and causation—each of which can be reliably assessed using social-science techniques. The brief emphasizes that the social-science methods for assessing these elements have developed substantially since the Court last considered partisan-gerrymandering claims in the mid-2000s. The law firm Orrick, Herrington & Sutcliffe is counsel for this brief.

Brief of Heather K. Gerken, Jonathan N. Katz, Gary King, Larry J. Sabato, and Samuel S.-H. Wang in Support of Appellees

Summary: This brief, filed by the Dean of Yale Law School in tandem with several other leading scholars of elections, encourages the Court to incorporate the partisan symmetry principle into its test for determining unconstitutional redistricting. The scholars explain that courts can assess the symmetry of maps reliably, transparently, and easily without undue reliance on experts. Additionally, the brief asserts, the choice of the particular metric for measuring symmetry does not matter in this case, because Wisconsin’s state assembly map would fail under any metric. Dean Gerken and the law firm Goldstein & Russell are co-counsel on this brief.

Brief of Eric McGhee in Support of Neither Party

Summary: This brief, filed by Eric McGhee, developer of the “efficiency gap” measure of partisan advantage on which the plaintiffs and the court below rely, explains the utility of the efficiency gap for diagnosing extreme partisan gerrymandering, outlines the distinct advantages of the measure, and responds to objections to its use in gerrymandering cases.  Professor Christopher S. Elmendorf of the University of California, Davis School of Law and the law firm Davis Polk & Wardwell are co-counsel for this brief.