High court to weigh partisan gerrymandering

Election maps have been struck down over race, but not politics.

The Supreme Court announced Monday that it would consider whether partisan gerrymandering violates the Constitution. The case could reshape U.S. politics.

In the past, the court has struck down election maps as racial gerrymanders that disadvantaged minority voters. But it has never disallowed a map on the ground that it was drawn to give an unfair advantage to a political party.

Some justices have said the court should stay out of such political disputes entirely. Others have said partisan gerrymanders may violate the Constitution. Justice Anthony M. Kennedy has taken a middle position, and the case could turn on his vote.

The court is quite likely to be closely divided when it hears arguments in the fall. Not long after the court agreed to hear the case, it issued an order suggesting as much.

The order granted a request to stay a decision by a lower court, which had struck down a legislative map as an unconstitutional partisan gerrymander, while the Supreme Court considers the case. The court’s four liberal members — Justices Ruth Bader Ginsburg, Stephen G. Breyer, Sonia Sotomayor and Elena Kagan — dissented. Kennedy was in the majority.

In a 2004 concurrence, Kennedy wrote that he might consider a challenge to political gerrymanders if there were “a workable standard” to decide when they crossed a constitutional line. But he said he had not seen such a standard.

The challengers in the new case, Gill v. Whitford, No. 16-1161, say they have found a way to separate partisanship from the many other factors that influence how districts are drawn.

The case arrives at the court in the wake of Republican victories in state legislatures that allowed lawmakers to draw election maps favoring their party.

The case started when Republicans gained complete control of Wisconsin’s government in 2010 for the first time in more than 40 years.

It was a redistricting year, and lawmakers promptly drew a map for the state Assembly that helped Republicans convert very close statewide vote totals into lopsided legislative majorities.

In 2012, Republicans won 48.6 percent of the statewide vote for Assembly candidates but captured 60 of the Assembly’s 99 seats. In 2014, 52 percent of the vote yielded 63 seats.

Last year, a divided three-judge U.S. District Court panel ruled that Republicans had gone too far.

The map, Judge Kenneth F. Ripple wrote for the majority, “was designed to make it more difficult for Democrats, compared to Republicans, to translate their votes into seats.”

The decision was the first from a federal court in more than 30 years to reject a voting map as partisan gerrymandering.

The new standard proposed by the challengers tries to measure the level of partisanship in legislative maps by counting “wasted votes” that result from the two basic ways of injecting partisan politics into drawing the maps: packing and cracking.

Packing many Democrats into a single district, for instance, wastes every Democratic vote beyond the bare majority needed to elect a Democratic candidate.

Cracking, or spreading, Democratic voters across districts in which Republicans have small majorities wastes all of the Democratic votes when the Republican candidate wins.

In a 2015 article, Nicholas O. Stephanopoulos, a law professor at the University of Chicago and a lawyer for the plaintiffs, and Eric McGhee devised a formula that measures partisanship.

The difference between the two parties’ wasted votes, divided by the total number of votes cast, yields an efficiency gap, they wrote.

In a world of perfect nonpartisanship, there would be no gap.

The gap in Wisconsin was 13.3 percent in 2012 and 9.6 percent in 2014, according to the formula.

The Wisconsin voters who sued to challenge the Assembly map argued that gaps over 7 percent violated the Constitution.

That number was meant to capture the likelihood that the gap would endure over a 10-year election cycle, but critics contend it is arbitrary.