BOEHM: Approach provides way to measure gerrymandering

Keywords Forefront / Opinion

The first federal constitutional challenge to a partisan gerrymander, Davis v. Bandemer, was tried in Indianapolis in 1982. The plaintiffs prevailed in the district court, but the Supreme Court reversed in a 4-3-2 decision. Until this year, all subsequent challenges were rejected on motion.

In January, this column reported that the federal court in Madison, Wisconsin, had denied pretrial motions to dismiss Whitford v. Gill, which challenged the 2011 redistricting of the Wisconsin Legislature as a partisan gerrymander that violated the U.S. Constitution. A trial was held in the Whitford case in May, and the three-judge court rendered its decision, with one dissent, shortly after the November election.

The majority concluded a successful claim required proof that a districting plan was drawn with the purpose and effect of creating partisan advantage. The majority found partisan purpose was obvious from the evidence. But what is required to prove an unconstitutional effect is a different matter. Prior cases established only what was insufficient, not what would be sufficient.

In recent rulings, four of the current eight U.S. Supreme Court justices have indicated a willingness to strike down partisan gerrymanders and offered views on what would violate the constitution. A fifth, Justice Kennedy, has rejected the view that districting is a subject the courts cannot address, but he has also rejected all of plaintiff’s proposed “standards” to judge a gerrymanderunconstitutional.

The majority in Whitford concluded that the flaw in prior plaintiffs’ cases was the failure to prove the partisan effect of the maps was greater than a single election. But the majority found the record in Whitford established that “in any likely electoral scenario, the number of Republican seats would not drop below 50 percent.”

Whitford plaintiffs proposed the efficiency gap as a measure of a gerrymander’s effectiveness. This compares the total of each party’s votes that made no difference, i.e. votes cast for losing candidates, and those for winners greater than the number required to win the seat. Otherwise stated, it compares the number of the two parties’ voters who could have stayed home without unseating a winner.

The efficiency gap is expressed as the percentage by which votes for candidates of one party are wasted compared to those wasted for the other. If 1 million voters for one party were wasted, and 1.1 million for the other, the gap is 10 percent.

The beauty of the efficiency gap is, it measures with precision exactly what a gerrymanderer sets out to accomplish: “Pack” as many of the opposing party’s voters into a minority of districts that the opponent wins by large margins and “crack” the opponents’ votes in those districts that are competitive to create as many as possible either “safe” or “leaning” districts for the gerrymanderer’s party.

A study of hundreds of elections revealed that, if the first election under a new map had an efficiency gap of 7 percent or more, there was a 95 percent or higher likelihood that the majority party would keep its majority throughout the decade until the next census required a new map.

The Wisconsin court will likely take some time to determine the appropriate remedy for the constitutional violation. Although an appeal to the Supreme Court is extremely likely, it might be 2018 before that court addresses these potentially groundbreaking issues with major implications for many states, including Indiana.•


Boehm is a retired Indiana Supreme Court justice who previously held senior corporate legal positions and helped launch amateur sports initiatives in Indianapolis. Send comments on this column to

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