Updated 11:30 a.m.

The Virginia Senate cleared a controversial congressional redistricting plan Friday, sending it to Gov. Robert McDonnell (R) for his signature after months of partisan squabbling.

The map, which reflects the results of the 2010 Census, passed the Senate on a 20-19 vote, with one Democrat — Sen. John S. Edwards (Roanoke City) — absent from the evenly divided chamber. The plan was approved by the state House last week on a mostly party-line vote.

The plan, which was authored by Republicans, would mostly strengthen the state’s incumbents lawmakers, likely preserving the current delegation split of eight Republicans and three Democrats. The measure passed the House in 2011 but was never taken up by the Democratic-controlled Senate, which advanced its own plan that would have created a second district with a significant minority population to go along with Rep. Bobby Scott’s (D) current seat.

The Senate approved the bill Friday following a brief but heated debate in which Democrats accused Republicans of diluting the rights of minorities. Republicans defended the map and suggested it had bipartisan support outside of the Senate.

The plan “preserves the core of each of the 11 congressional districts, protects communities of interest and the cores of existing districts,” said Sen. Mark Obenshain (R-Harrisonburg), adding that the map got the approval of all of the state’s current members of Congress.

But Sen. Mamie E. Locke (D-Hampton) said the map was “clearly designed to protect incumbents without giving the minority population the opportunity to vote for candidates of their choice.”

Though the bill is ready to become law, it still must receive approval from the U.S. Justice Department to ensure it complies with the Voting Rights Act. And it is the subject of lawsuits in state and federal court, contenting that the General Assembly violated the Virginia Constitution, which says new district lines “shall” be drawn in 2011.

“The constitution is quite clear,” said Sen. George L. Barker (D-Fairfax). “It does not provide leniency, it does not provide latitude to get that done in any other year.”

Republicans countered that the General Assembly has passed redistricting bills in past years that didn’t immediately follow the census, and the Constitution permits allowed them to take Friday’s action.

“I respectfully submit that it is proper, indeed it is our duty, to act on this now,” Obenshain said.

U.S. House Majority Leader Eric Cantor (R-Va.), whose political aides played a key role in drafting the map, praised the Senate’s action.

“This legislation was the only plan presented which enjoyed both bipartisan and biracial support,” Cantor said in a statement. “It is a unity plan that represents compromise by both parties, and enjoys broad community support as well.”