For the last decade, the Supreme Court of the United States has openly refused to police partisan gerrymandering even in egregious cases where the state legislature or its congressional delegation bears little resemblance to the will of the people. A new study out of Duke University, however, casts serious doubts on the reasoning of the justices who have thus-far refused to strike down unconstitutional gerrymanders.
In 2012, Democratic U.S. House candidates in North Carolina received 81,190 more votes that Republicans. Republicans received just under half of the votes earned by the two parties. And yet, the GOP walked away with 9 of the state’s 13 congressional districts. So, despite the fact that they earned just over 49 percent of the two-party vote, Republicans won nearly 70 percent of the state’s congressional seats.
Common sense dictates that the legislative maps that could produce such a result must be deeply flawed — and that they must be biased towards Republicans, the same party that controlled both houses of the state legislature when these maps were drawn (although the state had a Democratic governor at the time of the redistricting, the governor has no veto power over congressional maps). A new study by Duke Mathematics Professor Jonathan Mattingly and undergraduate Christy Vaughn seems to confirm this insight. Their study confirms that it is highly unlikely that a fair redistricting process would have produced a map as skewed towards one political party as North Carolina’s congressional map is.
Mattingly and Vaughn’s study redrew numerous random congressional maps, all of which complied with three rules: the districts must be “connected,” they must “come as close as possible to having [an] equal number of people,” and “they should be as compact as possible.” They then ran eight different simulations, some of which gave greater preferences to compact districts over equal population, while others placed greater emphasis on maintaining exact population. Seven of the eight simulations did not produce a single map where Democrats won less than five congressional seats, assuming that every voter who cast a vote for a Democrat or a Republican in 2012 would have cast the same vote under the simulated maps. The one simulation that did produce a handful of outlier maps where Democrats won only four seats did so “in less than 5% of the samples.”
Thus, the actual result of the 2012 elections — four Democratic congressional seats in North Carolina — did not even show up in all but one of Mattingly and Vaughn’s simulations. In the simulation where it did arise, it did so only in a few unusual cases. It is exceedingly unlikely that North Carolina’s GOP-friendly maps could have arisen organically. Rather, as Mattingly and Vaughn demonstrate, they are almost certainly the product of a legislature that carefully designed the maps to produce a desired result. The study’s authors argue that this result cries out for an independent check on redistricting — “The fact that the election outcomes are so dependent on the choice of redistrictings demonstrates the need for checks and balances to ensure that democracy is served when redistrictings are drawn and the election outcome is representative of the votes casted.”
Which brings us back to the Supreme Court. In the 2004 case Vieth v. Jubelirer, a total of four conservative justices joined an opinion by Justice Antonin Scalia arguing that federal courts should not get involved in partisan gerrymandering cases. The essence of Scalia’s argument in Vieth is that courts are simply unable to come up with a legally manageable standard for determining which gerrymanders cross the line when they become impermissible. According to Scalia, “no judicially discernible and manageable standards for adjudicating political gerrymandering claims have emerged.”
Justice Anthony Kennedy wrote a separate opinion in which he also lamented the fact that such a standard has not yet emerged — although he seemed more open than Scalia to the possibility that it could emerge in the future. “When presented with a claim of injury from partisan gerrymandering,” Kennedy wrote, “courts confront two obstacles.” The first is a “lack of comprehensive and neutral principles for drawing electoral boundaries,” and the second is “the absence of rules to limit and confine judicial intervention.” While judges might have an intuition that a particular gerrymander crosses the line where it unconstitutionally favors the members of one party over another, Kennedy was not aware of any “comprehensive and neutral principles” that could be used to judge each congressional map to determine whether it crossed the line.
That is the genius of Mattingly and Vaughn’s study. It creates an objective methodology for assessing whether a map is impermissibly gerrymandered. Admittedly, judges would still have to apply some discretion to determine how skewed a map must be before it must be struck down. What if 10 percent of the maps produced using Mattingly and Vaughn’s methodology were in line with actual election results? What the number were 20 percent? But in truly egregious cases like North Carolina, any reasonable judge can recognize that the map could not have resulted from a fair and neutral process.
That doesn’t mean, of course, that the Court’s present majority — all five members of the Court’s current conservative bloc have expressed at least some reluctance to decide partisan gerrymandering cases — will allow judges to reach this question. Should the Court’s majority change in the coming years, however, Mattingly and Vaughn may have provided that new majority with the tools they need to eliminate North Carolina-style gerrymandering in the future.