By Colleen Jenkins
WINSTON-SALEM, N.C. (Reuters) - The Supreme Court on Monday threw out a lower court ruling that upheld a legislative redistricting plan in North Carolina decried by critics as an effort to diminish the influence of black voters.
Justices ordered the North Carolina Supreme Court to reconsider its December ruling, which found the voting maps drawn in 2011 by the state's Republican-led legislature constitutional, in light of a decision by the nation's highest court in a similar case in Alabama.
The Supreme Court in that case found the Alabama court erred in the way it evaluated the plan. The Supreme Court did not comment on the substance of the North Carolina ruling.
The groups challenging the North Carolina redistricting plan argue it constitutes unlawful racial gerrymandering designed to give Republicans a political advantage.
Critics say such plans are used by U.S. states to shift black voters into areas they already dominate to dilute their political influence elsewhere.
"We applaud this decision as an important step in overturning the biased redistricting plans that aggressively promote segregation in order to help a partisan political agenda," said the nonpartisan Democracy North Carolina, one of the groups contesting the voting maps.
The court's order stopped short of saying whether the plan violates the U.S. Constitution's guarantee of equal protection under the law by packing black voters, who tend to vote Democratic, into a small number of districts.
Instead, justices instructed the North Carolina court to revisit the case in light of their 5-4 decision in March that found an Alabama court's ruling backing that state's redistricting plan "legally erroneous."
Justice Stephen Breyer, writing for the majority in the Alabama case, said the lower court should have considered the claims district-by-district rather than the state as a whole.
The two legislators who chaired committees that authored North Carolina's maps said the justices' order on Monday did not indicate how they would rule on the merits of the case, which the lawmakers said involves different legal arguments than the Alabama case.
State lawmakers have argued their maps satisfied the requirements of the Voting Rights Act, a federal law aimed at protecting minority voting rights.
"Today’s procedural ruling is not unexpected, and we are confident that our state Supreme Court will once again arrive at the same result and the U.S. Supreme Court will affirm its decision," Representative David Lewis and Senator Bob Rucho said in a joint statement.
(Reporting by Colleen Jenkins; editing by Andrew Hay and Cynthia Osterman)