Eric Kashdan

Computer Modeling the Gerrymander

On October 3, the Supreme Court will hear oral arguments in Gill v. Whitford, a case that demonstrates both the promises and pitfalls that arise when modern technology meets election law. On appeal is a 2016 decision by the U.S. District Court for the Western District of Wisconsin, in which a three-judge panel found that Wisconsin’s 2010 legislative redistricting plan was an unconstitutional partisan gerrymander.1 It was the first such ruling in thirty years.2 The promise of technology is apparent in this case because the district court, in part, reached its verdict with the aid of advanced computer modeling that statistically demonstrated the partisan skew of Wisconsin’s legislative maps.3 The pitfall arose earlier in the creation of these challenged districts, for Wisconsin political operatives had used similar software to create the most effective gerrymander possible.4

Partisan gerrymandering is among our nation’s oldest political problems.5 Long predating computers, it traditionally works in one of two ways. “Either a party cracks (that is, splits) the other party’s voters among many districts in which their preferred candidates lose by relatively narrow margins. Or a party packs the other side’s voters into a few districts in which their preferred candidates win by overwhelming margins.”6 Whichever party controls a majority in the state legislature controls the redistricting process, and can thus create maps that favor their electoral candidates.

Wisconsin legislators demonstrated how modern technology can enhance gerrymandering during their 2010 redistricting process. State Republican leaders hired political operatives to create computer modeling programs to measure partisanship across territorial and demographic areas, draw proposed legislative maps, and run regression analyses to assess how these districts would perform across a range of conceivable electoral outcomes.7 The results of these algorithmic calculations “allowed the mapmakers to distribute voters with maximum advantage for Republicans, without fear of spreading their own supporters too thinly and thus imperiling safe seats.”8 The success of these operations showed in the next elections; Republicans captured sixty of Wisconsin’s ninety-nine state assembly seats with only 48.6% of the statewide vote in 2012, and sixty-three seats with just 52% of the vote in 2014.9

Options for fighting such biased redistricting tactics are limited. Although the Supreme Court previously held that partisan gerrymandering could be unconstitutional under principles of equal representation, the Justices have never agreed on a justiciable standard for measuring when partisan redistricting has gone too far.10 Thus, in the last partisan gerrymandering case heard before the Court, Vieth v. Jubelirer, a plurality of Justices argued that the failure to find a standard must mean one does not exist, and partisan gerrymandering is outside the scope of judicial review.11

Importantly, however, Justice Kennedy cast the deciding fifth vote and did not agree with this reasoning. Instead, he wrote a concurring opinion proclaiming, “[t]hat no such standard has emerged in this case should not be taken to prove that none will emerge in the future.”12 Ever since, advocates have searched for a working standard that would persuade Justice Kennedy to join the minority from Vieth in adopting a constitutional test that could end partisan gerrymandering.13

The plaintiffs in Gill v. Whitford are now proposing a technological solution. As part of a three-part test, an essential component of the plaintiffs’ case is statistical evidence of partisan bias generated using the plaintiffs’ own computer algorithms. Specifically, by using modern software to simulate legislative districts drawn along nonpartisan lines, the plaintiffs compared Wisconsin’s recent election results with what those results would have been in alternatively drawn districts with the same vote count.14 This facilitated a statistical comparison that the plaintiffs call an “efficiency gap,” a figure that ultimately demonstrated the breadth of Wisconsin’s partisan gerrymandering.15 The district court was persuaded and found Wisconsin’s districts unconstitutional, leading to the current appeal.16

Ultimately, technology may not be the deciding factor in Gill v. Whitford. Nevertheless, the role of computer modeling and advanced algorithms in this case firmly demonstrates the growing impact of modern technology on election law. No matter the outcome for gerrymandering, these two fields will continue to intersect, ensuring that similar promises and pitfalls will arise again.

GLTR Staff Member; Georgetown Law, J.D. expected 2019; Boston University, B.A. 2014. ©2018, Eric Kashdan.