A panel of three federal judges Monday struck down state house district maps drawn in 2011 by Wisconsin's Republican controlled legislature, finding the resulting districts so blatantly partisan that they denied Democrats a fair shot at electing candidates of their choosing.

The case could now go directly to the U.S. Supreme Court, where Democrats hope it will provide the justices a legal test that has for decades proven to be elusive — a way to tell how much partisanship is too much.

"There is no question," said the 2-1 ruling, that the map drawn by Wisconsin's legislature "was designed to make it more difficult for Democrats, compared to Republicans, to translate their votes into seats."

The judges added, "It is clear that the drafters got what they intended to get."

The court said both the First Amendment and the Constitution's guarantee of equal protection prohibit redistricting plans that make it harder for members of a disfavored political party to elect their candidates and that cannot be justified on legitimate grounds.

Related: Supreme Court Upholds Arizona Redistricting Board

The disputed map was drawn after Wisconsin's 2010 election produced Republican control of the state assembly, state senate, and the governor's office for the first time in more than 40 years.

William Whitford, a retired law school professor, and 11 other Democrats challenged the resulting map as an unconstitutional partisan gerrymander.

Their lawsuit claimed that Republicans spread Democrats thin among some districts so that they could not achieve a majority. And in other areas, they said, Republicans packed Democrats into a few districts to limit their ability to control more seats.

The court found that the plan was intended to entrench one party in power over the life of the districting plan. As proof, the judge accepted a standard the Democrats offered in their lawsuit -- the voting "efficiency gap."

It was statistical measurement of how many votes in each party were wasted, either because they were so diluted in a district they could never achieve a majority or because they were so concentrated in a district that they were in excess of what was needed to get a majority.

Related: SCOTUS Unanimously Rejects Challenge to 'One Person, One Vote'

Ruth Greenwood of the Campaign Legal Center, who helped argue the case, called Monday's ruling historic.

"For the first time in thirty years, a federal court has found a district plan to be an unconstitutional partisan gerrymander. If this holds up on appeal, dozens of state legislative plans will be vulnerable," including maps drawn in Florida, Ohio, North Carolina, and Virginia.

Gov. Scott Walker and Wisconsin's attorney general were said to be reviewing the decision.

Paul Smith, a Washington, DC lawyer who has argued several redistricting cases before the Supreme Court, said the case is virtually certain to go before the justices.

"There's a meaningful chance this case could provide the kind of evidence needed to satisfy the court's quest for a standard, a way to tell how much partisanship is too much."

Monday's ruling was written by Judge Kenneth Ripple, appointed by Ronald Reagan. It was joined by Judge Barbara Crabb, a Jimmy Carter appointee.

Judge William Griesbach dissented. He said the test used by the majority is not an appropriate one in a system that gives the political branches of government the power to draw district maps.

"If political motivation is improper, then the task of redistricting should be constitutionally assigned to some other body."

The ruling gave both sides 30 days to propose a remedy. But if the state appeals, that process would likely be put on hold.

Editor's note: Because of a typographical error, this story originally said the districts were redrawn in 2001, rather than 2011.