Redistricting shapes the power of political parties. When states redraw their electoral maps every 10 years, they alter the relative power of parties by changing the partisan makeup of each district. And when states engage in gerrymandering by creating districts with the intent of reducing the electoral weight of certain categories of voters, we should be even more concerned. The U.S. Supreme Court heard oral arguments for a particularly important redistricting case on October 3. In this case, Gill v. Whitford, the Court addressed the legality of gerrymandering for partisan purposes. To answer these questions, the Court must resolve how lower courts can and should approach the use of scientific and statistical expertise regarding partisan gerrymandering.
Recent advances in computer-aided redistricting, fueled by “big data,” have raised the stakes for the court. Traditional districting principles such as compactness and respect for political boundaries can provide only a token check on the increasingly automated pursuit of maximal partisan advantage. By ruling in favor of the plaintiffs, the court could constrain partisanship in the redistricting process and require that elections officials give weight to nonpartisan scientific and statistical expertise. Indeed, it could use this case as a vehicle to define the legal standards governing redistricting nationwide in future elections.
If the court rules against the plaintiffs, however, it would allow elections officials to interject partisan considerations into the redistricting process virtually unimpeded, weakening the relationship between political participation and election results and overriding the compelling research findings of nonpartisan experts.