U.S. Chief Justice John Roberts Jr. hates gerrymandering cases. When courts overturn legislatures’ redistricting maps, “you’re taking these issues away from democracy” and deciding them on what “I can only describe as sociological gobbledygook,” Roberts said in October during oral arguments in a Wisconsin redistricting case, Gill v. Whitford.

For years the U.S. Supreme Court has been unwilling to tackle partisan gerrymandering. That left state political parties free to redraw voting maps in egregious ways using ever more powerful software. But the high court may finally be ready to crack down on extreme cases of gerrymandering. It’s taking up two cases this term, including the one in Wisconsin, where Democrats are challenging the Republican-drawn map used to elect the state assembly. The other, Benisek v. Lamone, which it will hear this spring, concerns a Democrat-drawn congressional district in Maryland.

Political scientists, statisticians, and other number-crunchers have worked hard to reassure the justices that it’s possible to decide cases in a way that won’t expose them to accusations of playing politics. The same sophisticated tools that legislatures use to give their party an advantage can also be used to judge when a party has verged into the realm of unconstitutional bias. “We totally know how to do this,” says Gary King, a political scientist at Harvard, who’s consulted for both major parties as well as independents and courts on redistricting issues.

Lower courts are also pressuring the high court to act. On Jan. 9 a three-judge federal panel came down against gerrymandering in a North Carolina case, saying judges should be open to “new academic theories”—a message that seemed to be aimed at the Supreme Court.

Those theories aren’t all new. King and a co-author, Robert Browning, came up with the principle of “partisan symmetry” in 1987. It says, simply enough, that districts should be drawn so the parties would achieve the same outcomes given the same number of votes. For example, if the lines are drawn such that Republicans win 80 percent of a state’s seats when they have only 55 percent of the votes, that’s fine—as long as Democrats would also win 80 percent of the seats when they have 55 percent of the votes.

King and two colleagues offered the partisan symmetry standard to the Supreme Court in a 2006 redistricting case, LULAC v. Perry. By King’s count, it was discussed and positively evaluated in three of the opinions, including the plurality one. Justice John Paul Stevens (since retired), joined by Justice Stephen Breyer, said it could be “a helpful (though certainly not talismanic) tool.” In the Wisconsin case, the Democrats say one way to assess partisan symmetry is through a measure called the “efficiency gap,” which looks at how many votes a party “wastes” by winning one district with a large margin while losing another by a whisker.

King argues that the Supreme Court should avoid drawing a sharp line between what’s acceptable and not, because that would encourage redistricters to “crawl right up to the edge.” Instead, he says, it should state the principle of partisan symmetry and make clear to both parties that if they violate it, the courts could take over redistricting in their states. “They’ll be scared to death” and will stay well away from the edge, King says.

As usual, the swing vote could be Justice Anthony Kennedy. In a 2004 case, Vieth v. Jubelirer, he joined a majority in upholding a Pennsylvania congressional map. But he refused to say that partisan gerrymandering claims aren’t “justiciable”—that is, courts aren’t capable of resolving them. That left open the possibility a standard could be developed. In the Gill v. Whitford arguments, Kennedy pushed a lawyer for the Republicans to concede that it would be unconstitutional for a state to pass a redistricting law explicitly written to favor one party or the other. That’s a step toward saying that extremely partisan redistricting could also be unconstitutional.

Kennedy, 81, is “getting older, and there’s a good reason to think he might want to establish a legacy to American democracy” by helping craft a standard for partisan gerrymandering, King says. If the court doesn’t come down on gerrymandering this term, it’s hard to see when it would. Says Richard Hasen, an election-law expert at the University of California at Irvine School of Law: “This is the use-it-or-lose-it moment.”

BOTTOM LINE - Two redistricting cases this term are raising the odds that the Supreme Court will finally say some voting maps are so partisan they violate the Constitution.