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Story highlights

Supreme Court held North Carolina illegally drew two congressional districts to pack them with African-American voters

Republicans control 10 US House seats; Democrats three

(CNN) —  

The Supreme Court struck down two congressional district maps in North Carolina Monday, holding that the state had engaged in an unconstitutional racial gerrymander.

The ruling is a victory for the black North Carolina voters who had argued the plans packed African-Americans in districts that already had a high percentage of African-Americans, thus diluting their presence in other districts.

As a result, the ruling sends the North Carolina legislature back to the drawing board – with significant potential implications for the 2018 midterm elections. The state has been nearly split along partisan lines in recent statewide elections – such as for governor and president – but Republicans control 10 US House seats compared to only three for Democrats.

“The Constitution entrusts states with the job of designing congressional districts,” Justice Elena Kagan wrote for the majority. “But it also imposes an important constraint: A state may not use race as the predominant factor in drawing district lines unless it has a compelling reason.”

RELATED: Supreme Court tackles racial gerrymander cases

“North Carolina voters deserve a level playing field and fair elections, and I’m glad the Supreme Court agrees,” said Gov. Roy Cooper, a Democrat elected last November.

“The North Carolina Republican legislature tried to rig congressional elections by drawing unconstitutional districts that discriminated against African-Americans and that’s wrong,” he added.

The case was heard before Cooper took office, and attorneys for North Carolina argued that the state finds itself in a bind. The Voting Rights Act requires that the legislature take race into consideration when drawing district lines.

Two districts were at issue and the court split differently on its votes. In District 1, the legislature increased black voting age population from 47.6% to 52.65%. The court struck that map 8-0. The black majority voting population was also increased in District 12 from 43.7% to 50.66%. The court struck that map down 5-3.

Justice Neil Gorsuch didn’t participate because he was not on the bench when the case was heard.

Steve Vladeck, CNN legal analyst and professor of law at the University of Texas School of Law, contributed to this report.