A federal lawsuit challenging the constitutionality of Wisconsin’s Republican-drawn state legislative district lines could have sweeping implications for gerrymandered districts nationwide.

After a century as a trailblazer for progressive democracy reforms, Wisconsin has become what one local union leader ruefully calls “a kind of laboratory for oligarchs to implement their political and economic agenda.”

This assessment, delivered by David Poklinkoski, president of International Brotherhood of Electrical Workers Local 2304, captures Wisconsin Democrats’ dim view of the brazenly partisan redistricting plan masterminded by GOP Governor Scott Walker.

But the redistricting plan, so central in empowering Walker and his legislative allies to roll back social reforms in Wisconsin, is now the target of a federal lawsuit. First heard by federal judges in May, the suit is now before an appeals court that is expected to rule this summer. That ruling could reverberate in other states around the country with heavily GOP-tilted electoral maps. While a few Democratic-controlled state governments have district maps that favor their party, the 2010 Republican electoral sweep set off a nationally-coordinated and harshly partisan round of redistricting in states where both the governor and legislative majorities were Republican.

Now, Republican-imposed plans in a number of other states—including Michigan, Ohio, Pennsylvania, Virginia, North Carolina, Florida, and Texas—stand to be affected by Wisconsin’s redistricting ruling, which will be handed down by the U.S. Seventh Court of Appeals. Such redistricting experts as Michael Li, chief counsel on the issue for the Brennan Center for Justice, predict the case could eventually land before the Supreme Court. The death of conservative Justice Antonin has altered the ideological balance on the now evenly divided court, and Li says Justice Anthony Kennedy has shown a strong interest in the case.

“The Wisconsin lawsuit is the most significant gerrymandering challenge in 30 years,” says Li. “This lawsuit could be a rare opportunity to contest unfair redistricting. It comes at a time when both the Supreme Court and the public are aware of the dysfunctionality of our legislative bodies.”

In Wisconsin, the redistricting plan imposed in 2011 was conceived in tight secrecy behind a private law firm’s closed doors as part of a large-scale national Republican strategy to block Democrats from power through the careful manipulation of state legislative district lines. The plan exaggerates actual GOP electoral strength and marginalizes Democratic voters, critics say. Indeed, it takes partisan gerrymandering to new heights, transforming what would otherwise be majority votes for Democrats into overwhelming Republican victories.

The Republican-rigged electoral map has been crucial in enabling Walker and the state’s GOP-controlled legislature to gut labor laws, weaken environmental protections, bestow new tax breaks on corporations, attack women’s reproductive rights, and reduce funding for the University of Wisconsin and public education in general.

Known as Whitford v. Nichol, the suit was brought by 12 Democratic plaintiffs who argue that the plan unfairly discounts the values of votes cast by Democrats. The Wisconsin Attorney General’s office has defended the map on the grounds that it is not a “gerrymander,” typically defined as a set of district lines with illogical and strangely-shaped borders, and drawn for ideological advantage.

But the state’s district map exemplifies the extremes to which Republicans have taken the political practice of gerrymandering districts for maximum political advantage. The result has been an indirect form of voter disenfranchisement.The plaintiffs charged that the redistricting violated their right to equal protection under the 14th Amendment. Further, as they asserted in their brief: “Extreme partisan gerrymandering is also contrary to core democratic values because it enables a political party to win more legislative districts—and thus more legislative power—than is warranted by that party’s popular support.”

Refracted through the lens of redistricting, electoral outcomes in Wisconsin fail to reflect voters’ intent, the suit alleges. “By distorting the relationship between votes and assembly seats, it causes policies to be enacted that do not accurately reflect the public will,” the plaintiffs asserted. “In the end, a political minority is able to rule the majority and to entrench itself in power by periodically manipulating election boundaries.”