In a 6-3 decision, the justices upheld a redistricting map drawn by South Carolina’s Republican Legislature and overturned a lower court ruling that called it a “stark racial gerrymander.”

At issue was whether the state legislators drew the districts for political or racial reasons.

All six Republican appointees were in the majority and said the legislators were motivated by partisan concerns, while the three Democratic appointees dissented and said voters were shifted based on their race.

In the past, the court had said that partisan gerrymandering is legal and as old as the nation, but racial gerrymandering is discriminatory and unconstitutional.

The justices reasoned that the Constitution permits elected officials to make decisions based on political considerations, but the 14th Amendment forbids the government from making decisions based on race.

Not surprisingly, however, those two principles come into conflict in the drawing of election districts. At issue in the South Carolina case was a congressional district in the Charleston area held by Republican Rep. Nancy Mace.

That district had regularly elected Republicans, but a Democrat won it in 2018 in what was described as a major upset. Mace ran in 2020 and won a narrow victory.

When the South Carolina Legislature redrew its seven districts in response to the 2020 Census, the mapmakers sought to shore up her district as a Republican stronghold. They shifted more than 30,000 Black voters from Mace’s district in Charleston into a Black-majority district held by Rep. James E. Clyburn, the state’s lone Democrat.

Lawyers for the NAACP Legal Defense Fund and the ACLU sued and argued the state’s redistricting plan was unconstitutional. They won a ruling from a three-judge court which said “race was the predominant motivating factor” in the drawing of Mace’s district.

Justice Samuel A. Alito Jr, speaking for the court, said the evidence showed that partisan motives were driving force.

“To untangle race from other permissible considerations, we require the plaintiff to show that race was the predominant factor motivating the legislature’s decision to place a significant number of voters within or without a particular district,” Alito said. He added that the plaintiffs did not show race was the dominant factor in drawing the districts.

Justices Elena Kagan, Sonia Sotomayor and Ketanji Brown Jackson dissented.

“What a message to send to state legislators and mapmakers about racial gerrymandering,” Kagan said in dissent. “Go right ahead, this court says to states today.”

Unlike other redistricting cases from Alabama and Louisiana, the immediate impact of the South Carolina case looks to be limited.

Civil rights lawsuits in Alabama and Louisiana led to the creation of a second Black-majority district where a Democrat could be elected. The South Carolina litigation did not involve a possible second Black-majority district.

In March, the three judges who had struck down Mace’s district issued an order that allows this year’s election to proceed using the state’s preferred map.