Justice Ruth Bader Ginsburg has suggested that it might be the most important case of the upcoming term. On October 3, the Supreme Court will hear oral argument in Gill v. Whitford, a challenge to the redistricting plan passed by Wisconsin’s Republican-controlled legislature in 2011. A federal court struck down the plan last year, concluding that it violated the Constitution because it was the product of partisan gerrymandering – that is, the practice of purposely drawing district lines to favor one party and put another at a disadvantage. The challengers argue that the redistricting plan would allow Republicans to cement control of the state’s legislature for years to come, even if popular support for the party wanes; the lower court’s decision, they contend, merely corrected “a serious democratic malfunction that would otherwise have gone unremedied.” By contrast, the state of Wisconsin counters that if the lower court’s decision is allowed to stand, it will open the door to “unprecedented intervention in the American political process.”
The Wisconsin case is not the Supreme Court’s first foray into partisan gerrymandering. When the Supreme Court tackled the issue 13 years ago, in a challenge to Pennsylvania’s redistricting plan, the justices were deeply divided. Four justices – Justice Antonin Scalia, joined by then-Chief Justice William Rehnquist and Justices Sandra Day O’Connor and Clarence Thomas – agreed in Vieth v. Jubelirer that courts should never review partisan-gerrymandering claims, because it is too hard to come up with a manageable test to determine when politics plays too influential a role in redistricting. Four other justices – Justices John Paul Stevens, Ruth Bader Ginsburg, David Souter and Stephen Breyer – disagreed; they would have allowed courts to review partisan-gerrymandering claims. The key vote in the case came (as it so often does) from Justice Anthony Kennedy, who agreed that the Supreme Court should stay out of the Pennsylvania case but left open the door for courts to have a role in reviewing partisan-gerrymandering cases in the future if a workable standard could be found.
Over several decades, federal courts – rather than the Wisconsin legislature – drew the state’s redistricting maps, after politicians could not agree on a plan. But in 2010, Republicans won control of both houses of the state legislature and the governor’s office, which led to the legislature, instead of the courts, redrawing the maps after the 2010 census. Republicans fared well in the two elections that followed: In 2012, they won 48.6% of the statewide vote, giving them 60 seats in the state’s 99-seat assembly, while in 2014 they won 52% of the vote, giving them 63 seats. By contrast, in 2012, Democrats won 51.4% of the vote but secured 39 seats, while in 2014 they won approximately 48% of the vote, which gave them 36 seats.