WASHINGTON — The Supreme Court on Wednesday further weakened the Voting Rights Act, ruling that a congressional map in Louisiana was a racial gerrymander even though it was drawn to comply with the landmark law aimed at protecting minority voters.

The justices, split 6-3 with the court's conservatives in the majority, told states they can almost never consider race when drawing maps to comply with Section 2 of the Voting Rights Act, which was enacted to protect minority voters who long faced discrimination in elections.

Conservative Justice Samuel Alito, writing for the majority, said that while there may be extreme situations where the use of race can be justified to draw a map, no such conditions existed in the Louisiana case. As a result, the new map was an "unconstitutional racial gerrymander," he added.

The decision means Louisiana will need to redraw its map. Other states could try to do so as well, although there is little time this year with primaries underway ahead of November’s midterm congressional elections. Louisiana's primary is May 16, just two weeks away.

Longer term, the ruling could lead to fewer minority-majority districts not just in Congress but also in state and local government, reducing the number of non-white elected officials.

While the court had previously assumed that states could consider race in seeking to comply with the Voting Rights Act, Alito wrote that "allowing race to play any part in government decision-making represents a departure from the constitutional rule that applies in almost any other context."

In justifying the court's change of course, Alito highlighted developments in recent years, including "social change" in the South, where most of the race-based redistricting challenges arise. He also cited the court's 2019 decision that paved the way to unfettered partisan gerrymandering.

As a result, when civil rights plaintiffs challenge newly-drawn maps, the state can argue as a defense that it was merely seeking to maximize partisan advantage. In the South in particular, party preference is often aligned with race, with most Black people voting for Democrats.

In a separate concurring opinion, conservative Justice Clarence Thomas, a longtime critic of the Voting Rights Act, said the ruling should "largely put an end" to a system that he saw as unlawfully dividing people into districts based on race.

The three liberal justices dissented, with Justice Elena Kagan writing that the "consequences are likely to be far-reaching and grave and that the ruling effectively "renders Section 2 all but a dead letter."

"Under the court’s new view of Section 2, a state can, without legal consequence, systematically dilute minority citizens’ voting power," Kagan said.

In interviews, voting rights advocates characterized the ruling as the end of redistricting cases under Section 2, arguing they will be impossible to win.