Several election-law scholars said the ruling was especially significant because it offered, for the first time, a clear mathematical formula for measuring partisanship in a district, something that had been missing in previous assaults on gerrymandering.The Western District of Wisconsin includes Madison, where the "natural political geography" is heavily Democratic. One way gerrymandering is done is by deliberately packing extra Democrats/Republicans into a district instead of spreading some of them around into districts where that party could become competitive. But Madison is a political unit that traditional principles of districting would keep together. So when is the party in power taking too much advantage — and how much should courts be trusted to push back that advantage?
The 2-to-1 ruling by the United States District Court for the Western District of Wisconsin said that the Legislature’s remapping violated both the First Amendment and the Equal Protection Clause of the 14th Amendment because it aimed to deprive Democratic voters of their right to be represented. “Although Wisconsin’s natural political geography plays some role in the apportionment process,” the court wrote, “it simply does not explain adequately the sizable disparate effect” of Republican gains in the State Assembly after the boundaries were redrawn.
In this case, the court was split 2 to 1. I would expect the Supreme Court — with its new Trump appointee — to reverse the decision. But I haven't yet read the case, and I'm wondering about this innovation that is the "clear mathematical formula for measuring partisanship."
Courts have generally agreed that some partisan advantage in redistricting is tolerable, in part because voters themselves are not spread equally across a state or district by party. But the plaintiffs in the case, 12 state Democrats represented by the Campaign Legal Center, had argued that the Wisconsin remapping was among the most sharply partisan in the nation.But isn't that because Democrats have gerrymandered themselves by living in Madison and Milwaukee? I can believe we are the most sharply geographically partisan state in the union. It didn't take power-grabbing legislators drawing new and devious lines to make that so. It can be partly or mostly the behavior of people choosing where to live and being like-minded with our neighbors.
Their lawsuit said that in the 2012 elections for the Assembly, Wisconsin Republicans won 48.6 percent of the two-party vote but took 61 percent of the Assembly’s 99 seats.That's like the way Hillary Clinton won the popular vote in the presidential election: Democrats crowd together in smaller parts of the overall territory. The math doesn't prove the lines were drawn aggressively to take partisan advantage. The state lines never move, and we see, in the national election, the effects of the people who are Democrats gerrymandering themselves. I'm skeptical of this "clear mathematical formula" as a measurement of what happened in the minds of the line-drawers.
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.That's simple, all right, but I'm very suspicious of the way that it is simple.