Just How Much Gerrymandering Is Unconstitutional? Wisconsin Plaintiffs Want the Supreme Court to Rule.

Advocacy groups and plaintiffs pushing a Wisconsin lawsuit, as well as political scientists around the country, hope to establish a standard for just how much politicians should be allowed to gerrymander political maps.

Arizona Independent Redistricting Commission attorney Mary O'Grady, left, speaks with Stephen Miller, a Casa Grande city council member, as they point to a possible map outlining the new congressional landscape during a 2011 meeting in Tempe. (AP Photo/Ross D. Franklin)

Every decade, when state legislatures across the country draw districts for themselves and their congressional delegations, some lawmakers violate voters’ constitutional rights by packing members of the minority party into as few districts as possible.

At least, that’s what the Supreme Court has hinted at in past rulings, when it wrote that extreme partisan gerrymandering can violate voters’ First and Fourteenth Amendment rights to freedom of speech and due process. The problem, the Court wrote in its 2006 League of United Latin American Citizens v. Perry decision, is that it can’t strike down gerrymandered maps without some sort of tool to determine exactly when district boundaries are skewed so drastically that they discriminate based on voters’ party affiliations. The winding, snake-like districts often used to illustrate gerrymandering aren’t necessarily signs of ill intent, and it’s often necessary to have some variation in how polarized or competitive districts are.

But the Wisconsin-based plaintiffs in a lawsuit filed this summer think that they have found the formula that the Court has been waiting for. And if they manage to push their case to the high court and win, the lawsuit’s consequences could extend from Wisconsin across the entire nation.

In a new U.S. District Court case, Whitford v. Nichol, the plaintiffs propose judging gerrymandering via a concept called the “efficiency gap,” based on an academic paper written in 2014 by political scientists Nicholas Stephanopoulos and Eric McGhee.

The proposal is surprisingly simple for such an arcane subject: Start by adding up each party’s “wasted” votes that don’t help them win a district. (If Party A wins 90 votes out of 100, 39 of its votes are wasted, since it only needs 51 for a majority. All 10 of Party B’s votes are also wasted in this scenario.) The difference between each party’s wasted votes, divided by the total number of votes cast, is the “efficiency gap.”

Across the Wisconsin State Assembly, Stephanopoulos and McGhee found a 13-percent efficiency gap in 2012 and 10-percent gap in 2014, both favoring Republicans. That translates to Republicans winning 13 percent more seats in 2012 and 10 percent more in 2014 than they would have under a map that treated members of both parties equally.

In Whitford, the plaintiffs use the efficiency gap to illustrate how steeply disadvantaged Democrats are in the state. But because Whitford is the first time that any plaintiffs have proposed this kind of test to measure the extremity of gerrymandering, the lawsuit’s repercussions could extend far beyond Wisconsin.

“A sweeping, nationwide Supreme Court victory is sort of the dream scenario,” said Stephanopoulos, who is also one of the lawyers working for the plaintiffs.

He added that he would also welcome a decision that only strikes down Wisconsin’s Assembly map, which would create a guideline for future lawsuits elsewhere. But Stephanopoulos expects the defendants to appeal to the Supreme Court if they lose.

If the Court rules in the plaintiffs’ favor, it could establish the efficiency gap test as an official measure for gerrymandering in all states. But in addition to having a measurement for how extreme gerrymandering is in any given state, the Court would have to actually define how big an efficiency gap would have to be in order to be unconstitutional.

Stephanopoulos’s and McGhee’s recommendation: 8 percent as the threshold for statehouses, and whatever percentage adds up to at least two seats for congressional maps.

By that measure, Florida, Ohio, Pennsylvania, and Virginia all have congressional maps that violate voters’ constitutional rights. At the state level, this measure would invalidate political boundaries in Idaho, Indiana, Kansas, Massachusetts, Michigan, Missouri, North Carolina, Ohio, Oklahoma, Rhode Island, Virginia, Wisconsin, and Wyoming.

These states won’t all necessarily have to draw new maps if Wisconsin’s Assembly map is ruled unconstitutional, though. The plaintiffs base their argument against Wisconsin’s map heavily—though not solely—on the efficiency gap measurement. Stephanopoulos said it’s possible a court will rule against Wisconsin’s maps without approving of this particular measurement or choosing a different percentage as the line in the sand against gerrymandering.

The efficiency-gap standard has already come under criticism. Its reliance on election results means that the standard could be thrown by uncontested races or the natural advantage that incumbents build up the longer they hold a seat, said Wisconsin Assistant Attorney General Brian Keenan, who is defending his state’s map. And if a “wasted” vote is a sign of discrimination, that would make nearly every vote for a third-party candidate a sign of gerrymandering, Keenan added.

Despite the Supreme Court’s hints that extreme gerrymandering could be unconstitutional, Keenan said it’s an inherent characteristic of having districts—rather than proportional representation—that the representation in legislatures isn’t equal to overall popular votes. Democrats now tend to live in more densely populated, urban areas, making it more natural to encircle a large number of them in a single district. The congressional district centered on Milwaukee, for example, is a deep-blue district where Rep. Gwen Moore has won at least 69 percent of the vote in every election since she first ran in 2004.

“Districting itself isn’t unconstitutional,” Keenan said. “By districting, you just group people, and what you’re supposed to do is look at communities of interest and grouping like people together. And if you do that properly and it ends up with certain groups not being able to convert seats as well, that’s just kind of the breaks, it seems like. It’s not a constitutional problem.”

If the efficiency-gap measurement is flawed, gerrymandering opponents have a backup plan. Common Cause, the political advocacy nonprofit, launched a competition this year for political scientists to submit their own gerrymander standards.

According to SUNY Binghamton professor Michael D. McDonald, who submitted the winning proposal along with assistant professor Robin Best, the competition’s goal was not necessarily to insert the standard into a lawsuit aiming for the Supreme Court. The standards could be accepted by independent state redistricting commissions or a state like Florida, where partisan gerrymandering was outlawed by constitutional amendment—but never actually defined.

McDonald and Best proposed comparing a party’s statewide vote with its percentage in the median district. Illegal gerrymandering will have occurred, by their standard, when a party consistently wins a majority of the statewide vote but loses the median district.

Once a court, commission, or legislature in some state accepts a gerrymandering standard, it will have significant long-term ripple effects, McDonald believes.

“Virtually every state, once they’re told that’s the standard, they play by those rules,” McDonald said.