On Tuesday, the U.S. Supreme Court is scheduled to hear arguments in a Wisconsin case that could reshape Congress and state legislatures if a majority of justices embraces a new formula to identify legislative districts that unfairly favor one political party.
In Gill v. Whitford, the high court will examine what constitutes partisan gerrymandering in redistricting, the once-a-decade re-drawing of legislative boundaries to reflect demographic changes revealed in the census.
With redistricting looming as the 2020 census nears, statehouses nationwide will be watching the case for guidance on how to create electoral maps that pass legal muster while retaining the legislative advantage of the majority party.
The 12 plaintiffs in Gill say Republicans in Wisconsin’s state assembly went too far in 2011 by drawing political districts that favored GOP candidates. Republicans won 60 percent of state assembly seats in 2012, but received only 49 percent of statewide votes.
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In a 2004 case, Vieth v. Jubelirer, the Supreme Court said excessive partisanship in redistricting is unlawful, said Justin Levitt, a professor at Loyola Law School in Los Angeles.
But the justices couldn’t agree on the two most important questions: How do you know what’s excessive? And whose job is it to say?
“Four justices said “we can’t ever tell, so it’s not our job to say,’” Levitt said. “Another four said ‘of course, we can tell, and here's how.’ And Justice (Anthony) Kennedy, playing the center Hollywood Square, said ‘I think it’s our job, but I haven’t heard a standard (to measure unfair partisanship) that I like yet. Feed me something.’”
Enter the “Efficiency Gap,” a mathematical formula that measures the effect of partisan gerrymandering through “wasted votes” cast for losing candidates — and a winning candidates beyond what was needed for victory.
If Democrats and Republicans wasted votes at an equal rate, an electoral map would have an efficiency gap of zero. But if one party wasted votes at a lower rate, the efficiency gap would be in their favor, indicating their voters were distributed more efficiently in order to translate their ballots into legislative seats.
In 2012, Wisconsin had an efficiency gap of 13.3 percent in favor of Republicans. Efficiency gaps higher than 7 percent reflect excessive unconstitutional partisan bias, according to Simon Jackman, a former Stanford University political science and statistics professor who now heads the U.S. Studies Centre at the University of Sydney.
In the first federal ruling to strike down a redistricting plan for partisan gerrymandering in more than 30 years, a three-judge district court panel held that Wisconsin’s efficiency gap data was “corroborative evidence of an aggressive partisan gerrymander that was both intended and likely to persist for the life of the plan.”
Efficiency gap data is also figuring prominently in legal challenges to electoral maps in North Carolina.
“The efficiency gap is a modestly good radar gun” for detecting partisan gerrymandering,” Levitt said. “If you want to know what’s excessive, it’s a pretty good tool to flag the especially bad actors.”
While both parties indulge in partisan gerrymandering, Democrats’ problems with redistricting stem more from their personal choices, according to a recent blog co-authored by Chris Winkelman, general counsel to the National Republican Congressional Committee.
“The biggest single problem with the efficiency gap is that it assumes that political populations are relatively evenly dispersed geographically,” Winkelman wrote, adding that Democrats are mainly clustered in urban areas, while Republicans dominate suburban and rural areas that encompass larger sections of electoral maps.
“Yet, in this case, the challengers are asking the court to force state legislatures across the country to fix the Democrats’ political geography problem….The court should roundly reject this invitation,” Winkelman wrote.
The Supreme Court has struck down redistricting plans that were drawn along racial lines, but have treaded lightly in cases alleging excessive partisan bias.
In the 2004 Vieth v. Jubelirer case, Justice Antonin Scalia argued that partisan gerrymandering cases shouldn’t be heard by the court because there’s “no judicially discernible and manageable standards for adjudicating” the claims.
Attorneys for the state of Wisconsin cite that glaring shortcoming as the basis for their Supreme Court appeal. They also claim the district court lacked authority to consider the case and that the disputed electoral map complied with traditional redistricting principles.
But plaintiffs in the Gill case lean heavily on Wisconsin’s efficiency gap data as part of a proposed three-part standard that could be used to evaluate partisan gerrymandering cases nationwide.
“There's no standard right now for winning partisan gerrymandering cases. None whatsoever,” said Danielle Lang, an attorney with the Campaign Legal Center, a Washington-based group representing the Gill plaintiffs. “It is certainly the goal of this case to set a standard that would say ‘you have to prove partisan intent. You have to prove an extreme and durable gerrymander that has an effect of partisan asymmetry. And you have to prove that there's no justification.’ And certainly, the efficiency gap is a useful tool in proving that standard."
If Justice Kennedy agrees that the efficiency gap and other corroborating evidence establish a sound legal standard for proving partisan gerrymandering, he’s widely expected to break a presumed 4-4 split in the case among the conservative and moderate justices.
“The conventional wisdom is it all comes down to Kennedy,” said Rick Esenberg, founder and general counsel of the Wisconsin Institute for Law and Liberty, a conservative group that filed a friend-of-the-court brief in support of the state of Wisconsin.
Kennedy sided with Scalia and the majority in Vieth. And in a concurring opinion, Kennedy wrote about “the failings of the many proposed standards for measuring the burden a gerrymander imposes.”
That’s why “courts must be cautious about adopting a standard,” Kennedy wrote. But if “workable standards do emerge,” he added, “courts should be prepared to order relief.”
The majority party in the state legislature typically controls the redistricting process and creates legislative districts with safe majorities of their likely voters. Minority party voters are often spread into multiple districts to dilute their influence or clustered into a few districts, which can limit their impact.
Both tactics, known as “cracking” and “packing” can allow the party in power to hold more seats.
The efficiency gap is actually the difference between both parties’ wasted votes in an election, divided by the number of votes that were cast.
“It aggregates all of a plan’s cracking and packing choices into a single number,” according to a 2014 article by efficiency gap creators Nicholas Stephanopoulos, a law professor at the University of Chicago, and Eric McGhee, a political scientist with the Public Policy Institute of California.
In a national analysis of state legislative and congressional districts from 1972 to 2012, Stephanopoulos and McGhee found the median efficiency gap was close to zero, suggesting both parties had an equal chance for fair representation.
“Contrary to claims that Republicans benefit from redistricting because of their more efficient spatial allocation, the typical (redistricting) plan in recent decades has not been notably skewed in either party’s favor,” Stephanopoulos and McGhee wrote.
It wasn’t until 2012, that they noted an “alarming rise” in the efficiency gap.
After routing Democrats in the 2010 elections, Republicans nationwide used 2010 census data along with high-tech computer software and mapping technology to craft favorable political districts at the expense of Democratic voters.
The national redistricting effort, dubbed “Operation REDMAP,” helped Republicans capture more seats in Congress and in state-level races in 2012, 2014 and 2016. Today, Republicans control both state legislative chambers in 31 states, while Democrats lead both chambers in just 12 states.
“The severity of today’s gerrymandering is therefore unprecedented in modern times,” Stephanopoulos and McGhee wrote.
The nation’s five most partisan-gerrymandered states, as measured by the efficiency gap, all benefit Republicans, according to an analysis by Azavea, a Philadelphia data analysis firm.
The GOP holds three additional congressional seats in North Carolina and in Pennsylvania, and two each in Michigan, New York and Texas, due to partisan gerrymandering, Azavea found.
Of the 21 other states where partisan gerrymandering provided one additional congressional seat, Republicans benefited in 13 states while Democrats won the advantage in eight.