RALEIGH, N.C. (AP) — North Carolina’s Republican-drawn congressional districts were challenged again Friday, this time on arguments that politics played too much of a role in boundaries that were redrawn this year after a court identified racial gerrymandering with a previous map.

The national election reform group Common Cause, the state Democratic Party and Democratic voters sued the state, Republican legislative leaders and Gov. Pat McCrory in federal court in Greensboro.

Those challenging the law want a three-judge panel to rule North Carolina’s 13 districts unconstitutional and prevent their use. A primary election was held in June using the boundaries. General election absentee ballots are to be distributed next month based on the maps, so blocking the maps for November’s election appears unlikely.

Some judges, even at the U.S. Supreme Court, have said partisan gerrymandering is incompatible with democratic principles. However, the term isn’t well defined in court rulings, and drawing district maps for political advantage has not been declared illegal.

But the time is ripe for a landmark ruling, Common Cause argues, after one of the authors of the updated map identified the new boundaries as a partisan gerrymander designed to maintain the Republicans’ 10-3 majority in the state congressional delegation.

“We believe the brazen partisan gerrymander in North Carolina has crossed the line and that the court will rule it unconstitutional,” said Common Cause President Karen Hobert Flynn said in a release. “This gerrymander has robbed hundreds of thousands of North Carolina Democrats and Republicans of their ability to elect the candidates of their choice to represent their interests in Washington.”

GOP legislators have called the current and previous congressional map legal and fair. They pointed out Friday the small number of counties and precincts the new boundaries split between districts.

The lawsuit “is just the latest in a long line of attempts by far-left groups to use the federal court system to take away the rights of North Carolina voters,” Rep. David Lewis and Sen. Bob Rucho, the General Assembly’s chief mapmakers, said in a release.

The lawsuit largely focuses on comments made by Lewis, R-Harnett, in February as the Republican-led General Assembly redrew maps first approved in 2011. They were redrawn in response to an earlier court ruling that struck down the majority black 1st and 12th Districts as illegal racial gerrymanders.

The updated map lowered the black voting-age population in the two districts well below 50 percent. Redistricting criteria agreed to by a committee determined racial data wouldn’t be used in drawing the maps, but election results since 2008 would.

The criteria also said the committee would seek to maintain the current 10-3 partisan makeup of North Carolina’s congressional delegation. The 2011 map had allowed state Republicans to take a majority and pad their advantage over time.

During committee debate, Lewis said he acknowledged “freely that this would be a political gerrymander,” but it “is not against the law.”

Lewis also proposed that “we draw the maps to give a partisan advantage to 10 Republicans and three Democrats because I do not believe it’s possible to draw a map with 11 Republicans and two Democrats,” the lawsuit said, citing the committee transcript.

Friday’s lawsuit contends the map violates four sections of the U.S. Constitution. The boundaries harm Democrats seeking to get elected to Congress in the 10 GOP-friendly districts and harms Democratic voters by spreading them out over the GOP-favored districts so their votes won’t matter, the lawsuit says.

Judges who struck down the 2011 congressional maps said in June they were troubled by Lewis’ comments but their hands were tied because no standards for judging partisan gerrymandering claims had yet emerged.

At the time, lawyers for the mapmakers denied there was any political gerrymandering, in part because Republicans must rely on Democrats and unaffiliated voters to win congressional seats. Republicans comprise 30 percent of registered voters in the state.

The redistricting lawsuit is one of several filed in North Carolina since 2011, when Republicans took over the legislature and drew congressional and legislative maps. A ruling following a federal trial on allegations of racial gerrymandering is pending. Common Cause identifies itself as a nonpartisan group and also has worked in Maryland against congressional districts favoring Democrats.