WASHINGTON (CN) - In a case Justice Ruth Bader Ginsburg referred to as the "most important" that will come before the court this term, the Supreme Court will hear a partisan gerrymandering challenge Tuesday that could change the drawing of U.S. political districts.
Gill v. Whitford comes to the Supreme Court from Wisconsin, where a federal court struck down the state's legislative map last year. The court held Republicans meticulously carved up the districts for the state Legislature to systematically favor their party over Democrats.
The Wisconsin government has defended the map by saying it is the result of an inherently political process that dates back to 19th century Massachusetts, when Gov. Elbridge Gerry and his fellow Democrat-Republicans carved out a district people at the time said looked like a salamander. The combination of Gerry's name and the shape of the district led to the term still in use today.
While challenges to racial gerrymandering have built decades of precedent for courts to follow, the casebook for political gerrymandering cases is thinner. Tuesday’s hearing in Gill v. Whitford will mark the first time in over a decade that the Supreme Court has heard a major partisan gerrymandering case.
In the 2004 case Vieth v. Jubelirer, the Supreme Court held 5-4 that the judiciary branch should stay out of partisan gerrymandering cases because of the lack of an appropriate test to determine when a legislature has gone too far.
"There have been cases since,” Loyola Law School professor Justin Levitt said in an interview of the 2004 case, “but that was the last time that the court as a whole really confronted the issue."
There are two reasons why the decision in Vieth might not spell doom for William Whitford and the other plaintiffs in the new challenge. First, of the justices on the court when Vieth was decided, only Clarence Thomas, Ruth Bader Ginsburg, Stephen Breyer and Anthony Kennedy remain on the bench, bringing new minds to the issue.
Second is Kennedy's concurring opinion in the case, where he said he was open to courts having a role in partisan gerrymandering cases if someone could develop a reliable test to determine when a legislature has gone too far with its map.
Whitford and his group have presented Kennedy with what they hope will be just such a test. Endorsed by the federal court that struck down the Wisconsin map, the test requires people challenging a map to show it was designed with "discriminatory intent" to produce a "large and durable" discriminatory effect that cannot be explained in any other way.
"All of the three elements of the test are built on what the court and different justices have said at different times that they're looking for," University of Chicago Law School professor Nicholas Stephanopoulos said in an interview.
Whitford's group uses a host of social-science metrics to support their claim that the Wisconsin map meets all three prongs of the test. One of the more important metrics is called the efficiency gap, and it measures the number of "wasted" votes in a given district, defined as votes cast either for a losing candidate or for a winning candidate in excess of the bare minimum needed to win the district.
There are two major ways legislatures can divide maps to favor one party over another. One strategy, called cracking, scatters a party's votes across multiple districts, spreading out the influence of a heavily partisan area and limiting its impact. The other strategy, called packing, bunches together large numbers of voters for one party to create a single, landslide district.
The efficiency gap, which Stephanopoulos developed, accounts for both of these differences, with a high number indicating a less efficient district. Whitford and the group do not propose a specific threshold number that determines when a partisan gerrymander is unacceptable.
"Now that we have quantitative metrics, it's possible to rank the different plans, to really assess the magnitude and the persistence of their partisan edge in a really rigorous way," said Stephanopoulos, who helped write the brief for Whitford.
Levitt compared the metric to a radar gun. While a police officer is likely to let a car go if he clocks it going 36 mph on a street with a 35 mph speed limit, he is unlikely to be so lenient on a car doing 65 down the same street.
"A big number is a way of saying hey, there's something funny here," Levitt said. "It's a way of raising a flag. Because a really big number indicates that things were probably not coincidental."
Often seen as the swing vote in contentious cases, Kennedy's opinion in Vieth showing his openness to a test for partisan gerrymandering means he is even more likely to garner the full focus of court watchers during Tuesday's arguments.
"This is a pure Kennedy," Richard Briffault, a professor at Columbia University Law School, said in an interview. "Unless somebody does something astonishing of the other eight, it's a pure Kennedy."
Gerry Hebert, who argued Whitford in the lower courts, described the arguments in the case as a "letter to Justice Kennedy" in an interview last month. Stephanopoulos agreed that the focus should be on the Reagan nominee.
"I think the conventional wisdom here is that it's likely to be a significantly divided court and if past opinions are any guide, it may well be Justice Kennedy who's the swing vote," Stephanopoulos said. "He's been the swing vote in the last couple of partisan gerrymandering cases and so there's not a lot of reason to think that the composition will have changed on this issue since the last couple of cases.”
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