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."

The Republicans’ heavily disproportionate share of legislative seats has represented a particularly blatant trampling of the popular will, critics say. For example, in Wisconsin’s 2012 Assembly races, Democratic candidates gathered 1.4 million votes to the Republicans’ 1.2 million. Yet the Republicans walked away with 60 state Assembly seats, while the Democrats were left with just 39. In 2014, Walker won re-election as governor with 52 percent of the vote, but Republicans won 63 of 99 Assembly seats, while the number Democrat-held seats shrank to 36.

The dramatic gap between Republicans’ actual share of the electorate and their vastly higher level of representation threatens democratic representation, the plan’s critics say.

In his closing statement May 27 to the judges in defending the GOP electoral map, Wisconsin Assistant Attorney General Brian Keenan insisted that this is what democracy looks like. “This is actually democracy,” Keenan stated. “The Republicans won the 2010 election. The Constitution gives them the right to [draw district lines].”

But the plaintiffs countered that the plan subverts democracy. “When a minority party stays in power, even though they garner fewer votes, then the health of our democracy depends on our courts to fix the problem,” declared Earle Peter, an attorney for the plaintiffs, at a news conference. “We have one of the worst partisan gerrymanders in modern political history.”

In drawing their controversial Wisconsin map, state Republicans ignored the successful model used in neighboring Iowa for the past 35 years. That state uses a nonpartisan state agency to adjust districts to keep pace with population shifts reflected in the Census held every 10 years.

But back in Wisconsin, the GOP super-majority created by the map has pushed through a conservative agenda that arguably does not enjoy strong public support. Even the right-of-center Milwaukee Journal Sentinel in 2015 noted in an editorial the close linkage between the GOP-drawn map and Walker’s successful enactment of legislation that severely weakened unions: Wisconsin’s new “right-to-work” law “is a reminder of the role redistricting has played in forging the party’s ironclad legislative majorities.”

The heavily-tilted Wisconsin redistricting has its roots in a national effort known as REDMAP (the Redistricting Majority) project, launched shortly after Obama’s 2008 election by the the Republican State Leadership Committee, a tax-exempt political group that backs GOP state legislative candidates. Led by former Republican National Committee chairman Ed Gillespie and supported by GOP operative Karl Rove, REDMAP coordinated a national effort to provide sophisticated technical support to Republicans drawing district lines at the state level. The project was designed to both magnify Republican representation in state legislatures and to carve up U.S. House districts in such a way as to give the Republicans a pronounced edge.

In developing their redistricting plan, Wisconsin Republicans received assistance from such friendly experts as University of Oklahoma political science professor Ronald Keith Gaddie. In testimony videotaped for the Seventh District judges considering the case, Gaddie explained that he had provided detailed data based on sophisticated mathematical formulae so that Republicans could shape districts to strengthen their hold on the legislature. Gaddie called the redistricting plan approved in 2011 “a map that makes an assertive move towards a Republican advantage.”

Gaddie’s work, like the entire redistricting process, was conducted without any public scrutiny. The immensely significant electoral map was crafted entirely behind closed doors at the Republican-linked law firm of Michael Best & Friedrich. The process of developing the plan, which cost state taxpayers about $2 million, was so secretive that Republican legislators were required to sign a pledge of confidentiality before being permitted to look at the map. And even then, the GOP legislators were allowed only to see the maps for their individual districts.

No members of the general public, news media, or Democratic legislators, were permitted to review the redistricting plan until days before it was rushed through the legislature with only one hearing by the Republicans in charge. The shroud of secrecy continued to envelop the districting plan when the redistricting plan was first challenged in 2011 by a lawsuit brought by the AFL-CIO, the Fair Elections Project, and Latino rights group Voces del la Frontera. In 2012, the three-judge panel considering that suit fined the Michael Best firm nearly $17,500 and warned its lawyers to stop “the sort of disinformation, foot-dragging, and obfuscation now being engaged in.”

In 2013, the judges again found that “fraud, misrepresentation, or misconduct” had likely taken place, and ordered a post-trial investigation into thousands of missing records. Ultimately, however, the federal judges in that lawsuit ordered only limited changes, to protect two primarily Latino districts covered by the Voting Rights Act. However, the judges’ ruling excoriated the Republicans’ redistricting process, and stated that “the people of Wisconsin deserve better” than this “peculiarly furtive process adopted by the majority party.”

Five years later, political scientists are testifying in the current lawsuit that Republicans employed strategies known as “cracking” and “packing” to diminish the number of seats that Democratic candidates could plausibly win, and throwing their legislative representation out of whack with their share of the popular vote. “Cracking” refers to breaking up concentrations of Democratic votes and diluting Democratic strength by parceling them out in small pieces to larger GOP bastions to virtually guarantee that Republicans win election. “Packing” is the process of concentrating as many Democratic voters as possible into a limited number of districts, so that their votes affect the outcomes of only a limited number of races.

The success of the Republican plan can be measured in what the plaintiffs’ lawyer and University of Chicago Law Professor Nicholas Stephanopoulos labeled, in remarks to the judges, the “efficiency gap.” This is the percentage of votes that effectively do not count when districts are so thoroughly dominated by one party. In almost 800 state legislative elections that Stephanopoulos has studied over the last 40 years, the average “efficiency gap” has actually been zero, suggesting that neither party gained an advantage from redistricting.

But the “efficiency gap” in Wisconsin after the state’s 2011 redistricting plan went into effect was a full 13 percent in favor of the Republicans in 2012 and 10 percent in 2014, according to research by Stephanopoulos.

“The 2012 figure is the 28th worst score in modern American history, out of nearly 800 total plans,” Stephanopoulos testified.

Defying precedent, the Republican-drawn electoral map splits up 58 of the state’s 72 counties, points out Matt Rothschild, director of the clean-government group Wisconsin Democracy Campaign.

But Democrats aren’t the only ones complaining about Wisconsin’s electoral map. While filed by Democrats, the lawsuit is backed by several former Republican legislators who have denounced the redistricting plan. The GOP ex-legislators argue that the imbalanced redistricting has made incumbent Republican lawmakers more vulnerable than ever to pressure from big-money campaign contributors. Since the lawmakers no longer have to pay attention to a diverse constituency, special-interest donors expect that legislators will automatically deliver on legislation that serves their narrow agendas, says Rothschild, of the Wisconsin Democracy Campaign.

“The majority of our legislators have been relegated to nothing more than pawns awaiting bills written by special interests themselves, and told how and what to do,” former Republican state Senator Dale Schultz told the Wisconsin State Journal.

The Wisconsin case illustrates one of the ways Republicans engage in voter disenfranchisement, voting rights advocates say. While progressives have focused heavily on the proliferation of “voter suppression” laws in Republican-controlled legislatures, redistricting has given the GOP yet another, if subtler, means to block the popular will and negate voting rights.

“Their [the plaintiffs’] right to vote is fundamental,” thundered the Campaign Legal Center’s Gerry Hebert, one of the lawyers representing the plaintiffs, in his closing arguments before the court. “It's our voice in the government. It's the only voice many of us have. It's not right to target people and harm them because of their voting history. What did they do? They had the nerve to participate in the political process and go to the polls.