By Mark Sherman, AP

WASHINGTON (AP) — The Supreme Court on April 29 struck down Louisiana’s second majority Black congressional district in a decision that could open the door for Republican-led states to eliminate Black and Latino electoral districts that tend to favor Democrats and affect the balance of power in Congress.

In a 6-3 ruling, the court’s conservative majority found in Louisiana v. Callais that the district, represented by Democrat Cleo Fields, relied too heavily on race. Chief Justice John Roberts had described the district as a “snake” that stretches more than 200 miles to link parts of the Shreveport, Alexandria, Lafayette and Baton Rouge areas.

“That map is an unconstitutional gerrymander,” Justice Samuel Alito wrote for the six conservatives.

The decision weakens a landmark voting rights law’s protections against discrimination in redistricting. It’s unclear how much is left of the provision, known as Section 2, the main way to challenge racially discriminatory election practices.

Not much, Justice Elena Kagan wrote in a dissent for the three liberal justices. “The consequences are likely to be far-reaching and grave. Today’s decision renders Section 2 all but a dead letter,” Kagan wrote.

The 1965 voting rights law, the centerpiece legislation of the Civil Rights Movement, succeeded in opening the ballot box to Black Americans and reducing persistent discrimination in voting.

Nearly 70 of the 435 congressional districts are protected by Section 2, election law expert Nicholas Stephanopoulos has estimated.

Alito wrote that “allowing race to play any part in government decisionmaking represents a departure from the constitutional rule that applies in almost every other context.” He said Section 2 is effectively limited to instances of intentional discrimination, a very high standard.

Kagan said the upshot of the decision is that states “can, without legal consequence, systematically dilute minority citizens’ voting power.”

The court heard the case for a second time in October and it’s not clear whether the decision was issued early enough for some states, including Louisiana, to consider a new round of redistricting ahead of the 2026 midterm elections, in which Republicans are trying to preserve a thin majority.

President Donald Trump had already touched off a nationwide redistricting battle to boost Republican chances.

Legislatures already are free to draw extremely partisan districts because of a 2019 Supreme Court decision.

The court’s decision was released as Florida legislators debated a proposed redrawing of the state’s congressional lines, submitted by Republican Gov. Ron DeSantis and intended to give the GOP a chance to pick up as many as four seats in the state’s U.S. House delegation.

Democrats in the Florida Senate urged the Republican supermajority to delay debate to at least offer lawmakers a chance to read the decision and consult lawyers on how it might affect DeSantis’ proposal. Republicans refused.

In the Supreme Court’s Louisiana ruling, the justices did an about-face from a decision in a similar case from Alabama in 2023 that led to a new congressional map for the state that sent two Black Democrats to Congress.

Roberts and Justice Brett Kavanaugh joined the three liberals to form a majority in the Alabama case. Both joined Alito’s opinion on April 29.

The Alabama decision also prompted Louisiana lawmakers to add a second majority Black district. About a third of Louisianans are Black and they now form majorities in two of the state’s six congressional districts. Alabama has a separate appeal pending at the Supreme Court.

Associated Press writer Sara Cline in Baton Rouge, La., contributed to this report.