A conservative majority of the U.S. Supreme Court on Thursday overruled a lower court decision that a newly drawn South Carolina congressional map advantaging Republicans was an unconstitutional “racial gerrymander” that diluted the power of Black voters, triggering a fiery dissent from the court’s liberal wing.

In its 6-3 decision, the Supreme Court said a three-judge panel had committed “clear error” in concluding that GOP Rep. Nancy Mace’s congressional district was illegally drawn using racial data to the disadvantage of Black South Carolinians. The court, in a majority opinion by Justice Samuel Alito Jr., said the panel had ”paid only lip service” to legal principles governing racial gerrymandering cases.