The Post editorial: The political battle to curb gerrymandering will continue, as steep as it may be.

Politicians have been manipulating legislative district lines in order to tip electoral results their way for about as long as the Republic has existed. The term “gerrymander” was coined 205 years ago. But the tools and methods have become far more sophisticated, resulting in extremely warped electoral maps that curb the ability of many Americans to obtain meaningful political representation.

For decades, the Supreme Court has kept its distance from this issue. But last Monday, the court announced that it will hear a challenge to one of the most egregious examples of partisan mapmaking, raising hopes that, after two centuries, the justices may find their way to setting some limits on this increasingly corrupt practice.

Wisconsin’s state legislative map, which the court agreed to consider, is epically unbalanced. “Wisconsin’s Assembly,” the map’s challengers note, “… bears no resemblance to its evenly split electorate. In 2012, Republicans won a supermajority of sixty seats (out of ninety-nine) while losing the statewide vote. In 2014 and 2016, Republicans extended their advantage to sixty-three and sixtyfour seats, respectively, even though the statewide vote remained nearly tied.” Democrats could gain a majority only with a massive electoral swing far outside historical norms. And if they don’t, Republicans will remain in charge after the next census, again will draw district boundaries in an abusive fashion and so will perpetuate the inequity indefinitely.

It is no big leap to conclude that a map in which one party has dramatically more “wasted” votes than another, on purpose — a map designed so that a 55 percent vote for one party results in a remark- ably different outcome from a 55 percent vote for another — offends the Constitution’s guarantee of equal protection and possibly free-speech rights, too, given that gerrymandering effectively punishes certain voters for their past political choices. “That is precisely why judicial intervention was necessary here,” the challengers assert, “to correct a serious democratic malfunction that would otherwise have gone unremedied.” If the court were to quash Wisconsin’s legislative map, it would deter future bad behavior by putting statehouses across the country on notice: Don’t go too far in rigging the system.

This is far from an easy call. How can judges distinguish between acceptable and excessive politicization? The challengers recommend that courts determine whether voting-map bias is significant, purposeful and has no legitimate justification. The state of Wisconsin argues that this test is still vague, relying on an “unspecified brew” of factors that would give judges far too much flexibility in tossing out lawmakers’ work. “One third of all legislatively drawn plans would fail” the test, the state reckons. Once involved, the court might trigger a long-running judicial intervention in the workings of the political branches of government. Redistricting, a power assigned to the legislative branch, could effectively become a judicial enterprise.

Yet from Maryland and Virginia to North Carolina and beyond, state legislatures controlled by both parties have been disgracefully willing to prioritize incumbent protection over voter rights. The justices may take a long time to rule, and they might well decline to strike down the Wisconsin map. In the meantime, then, the political battle to curb gerrymandering must continue, steeply uphill though it may be. The members of The Denver Post’s editorial board are William Dean Singleton, chairman; Mac Tully, CEO and publisher; Chuck Plunkett, editor of the editorial pages; Megan Schrader, editorial writer; and Cohen Peart, opinion editor.