A panel of three federal judges said on Monday that the Wisconsin Legislature’s 2011 redrawing of State Assembly districts to favor Republicans was an unconstitutional partisan gerrymander, the first such ruling in three decades of pitched legal battles over the issue.
Federal courts have struck down gerrymanders on racial grounds, but not on grounds that they unfairly give advantage to a political party — the more common form of gerrymandering. The case could now go directly to the Supreme Court, where its fate may rest with a single justice, Anthony M. Kennedy, who has expressed a willingness to strike down partisan gerrymanders but has yet to accept a rationale for it.
In Monday’s ruling, the court was swayed by a new and simple mathematical formula to measure the extent of partisan gerrymandering, called the efficiency gap. The formula divides the difference between the two parties’ “wasted votes” — votes beyond those needed by a winning side, and votes cast by a losing side — by the total number of votes cast. When both parties waste the same number of votes, the result is zero — an ideal solution. But as a winning party wastes fewer and fewer votes than its opponent, its score rises.The case will automatically go to the Supreme Court and we will have to watch this carefully, since gerrymandering for clearly political purposes was undertaken by many states after the 2010 census because Republicans won a lot of seats that year both in Congress and in state legislatures. Since the latter groups still draw the boundaries in a majority of states, this has almost certainly influenced politics in America, as things suggested they would back in 2011 as redistricting was taking place throughout the country. If boundaries are required to change in ways so that one party is clearly not benefitting more than another, this could affect elections in 2018 and 2020, which could then influence how the 2020 census data will be used for redistricting.