Nine Maryland voters filed a lawsuit at the U.S. District Court in Greenbelt Thursday, alleging that the state’s new congressional district map violates the Voting Rights Act by diluting the electoral strength of minorities.

Organized by the Fannie Lou Hamer Political Action Committee and a handful of other groups, the complainants want the current plan — which was signed into law by Gov. Martin O’Malley (D) last month — thrown out. They asked the court for “the creation of congressional redistricting plans that will not cancel out, minimize or dilute the voting strength of African American voters in Maryland.”

Democrats in Annapolis drew the new map with an eye toward making reelection difficult for Rep. Roscoe Bartlett (R) in the 6th congressional district. In the process, they split Montgomery County into three districts all currently represented by white men, and took away the portion of Montgomery currently held by African-American Rep. Donna Edwards (D).

Edwards was highly critical of the map and tried unsuccessfully to rally support against it in the state Legislature. Republicans also attacked the map as a classic example of partisan gerrymandering, and the state party said Thursday it supported the lawsuit.

“We join the Fannie Lou Hamer PAC, the Legacy Foundation, Marylanders for Fair and Coherent Representation, and citizens from across Maryland to reaffirm our belief that redistricting should not be done solely on partisanship or incumbent preference,” said Maryland Republican Party Chairman Alex Mooney. “We are eager to see the Governor’s map remedied so that the rights of all Marylanders, regardless of race, geography or political affiliation, are not denied.”

While the new map has its critics, defenders point out that it preserves the two current African-American majority districts and sets up the possibility that a third seat, held now by Rep. Steny Hoyer (D), could be won by a black candidate when Hoyer retires.