The Supreme Court on Tuesday will consider whether a state’s legislative maps are so politically skewed to favor one party that they violate the Constitution.
The justices have never thrown out a state’s maps because of partisan gerrymandering. But challengers from Wisconsin say they have the evidence that Republican leaders of their state drew maps to ensure enduring GOP control of the legislature, and a test for deciding when political advantage goes too far.
The outcome could change the way American elections are conducted. Wisconsin officials say if their maps, which follow traditional redistricting standards, are illegal, dozens of state plans will need to be thrown out.
Waiting in the wings are gerrymandering complaints from North Carolina and Maryland. The Maryland case alleges that the state’s Democratic leadership drew congressional maps that put Republicans at a disadvantage.
The Supreme Court routinely makes states redraw maps when there is evidence that drawing of legislative maps harms racial minority voters by making it more difficult to elect representatives of their choice.
Individual justices have said partisan gerrymandering is harmful as well. But even some of those who agree have said redistricting is a political question between representatives and their constituents, and the courts should stay out.
Others — most importantly Justice Anthony M. Kennedy, the key to the Wisconsin case — have said extreme partisan gerrymandering can violate constitutional rights. But in the court’s most recent look at the issue in 2004, he did not find a workable test for deciding what is excessive.
In the Wisconsin case, a panel of three federal judges ruled 2-to-1 that the state’s leaders had used a secretive process for drawing the maps after the 2010 census that went too far.
The lower court concluded that the districting plans were drawn to create districts favorable to Republicans, that the advantage would be “enduring” even when Democrats outperformed Republicans at the polls and that the drawing of the districts could not be explained by nonpartisan reasons.
They said Republicans packed Democrats into some districts and spread them out across others as a way to create more districts conductive to a GOP candidate.
The plans, developed in 2011 by Republican leaders who controlled the legislature and signed by Gov. Scott Walker (R), were effective.
In the election held after the new district maps were adopted, Republican candidates got just 48.6 percent of the statewide vote, but captured a 60-to-39 seat advantage in the State Assembly.
Evidence uncovered during lawsuits over the redistricting found that models showed Democrats would have to win about 53 percent of the statewide vote to capture a bare majority of the seats.
Republicans counter that it is political geography that explains the Democrats’ uphill task. They say their political opponents are clustered in the cities of Milwaukee and Madison, making it impossible to draw maps that would give them an advantage.
The case is Gill v. Whitford.