WASHINGTON – The Supreme Court ruled Thursday that Alabama’s new congressional map likely violated the Voting Rights Act, handing a win to black voters in a a closely-watched case that will now force the state to create a second House district with a large minority population.

Chief Justice John Roberts and Justice Brett Kavanaugh split from their conservative peers, joining the court’s three liberals in affirming a lower court’s ruling that Alabama’s current district lines unlawfully diluted the state’s black vote.

About a quarter of Alabama’s population is African-American, but just one of the seven congressional districts contested in the 2022 elections has a majority black population.

A group of black voters, aided by the National Redistricting Foundation, challenged the map under Section 2 of the 1965 civil rights law, which prohibits voting practices that discriminate based on race.

Ultimately, the Court agreed with the lower court’s decision that Alabama’s map would “likely” meet the three conditions to prove a violation of the law: the minority group is “sufficiently large and [geographically] compact,” “politically cohesive” and the white majority “votes as a bloc to sufficiently … defeat the minority’s preferred candidate.”

Attorney General Merrick Garland hailed the decision, saying it “preserves the principle that in the United States, all eligible voters must be able to exercise their constitutional right to vote free from discrimination based on their race.”

“The right to vote is the cornerstone of our democracy, the right from which all other rights ultimately flow,” he said in a statement.

Alabama had contended that the Court could not use Section 2 to decide the case because its map was protected under the 1980 ruling in City of Mobile v. Bolden, which found that voting structures not purposely made to discriminate do not violate the act, even if it is effects are discriminative in practice.

The majority rejected the notion, with Roberts writing: “This understanding of Section 2 cannot be reconciled with our precedent … we have applied Section 2 to States’ districting maps in an unbroken line of decisions stretching four decades.”

The chief justice cited case law that found a voting district “is not equally open … when minority voters face—unlike their majority peers—bloc voting along racial lines, arising against the backdrop of substantial racial discrimination within the State, that renders a minority vote unequal to a vote by a nonminority voter.”

Alabama further denied that the map was intentionally drawn to discriminate against black voters, arguing that it “sufficiently ‘resembles’ the [roughly two million] ‘race-neutral’ maps created by the state’s experts – all of which lack two majority-black districts.”

Roberts was unimpressed, writing: “Alabama’s insistent reliance on that number, however powerful it may sound in the abstract, is thus close to irrelevant in practice. What would the next million maps show? The next billion? The first trillion of the trillion trillions? Answerless questions all.”

The other four conservative justices dissented Thursday.

Justice Clarence Thomas wrote that the decision forces “Alabama to intentionally redraw its longstanding congressional districts so that black voters can control a number of seats roughly proportional to the black share of the State’s population. Section 2 demands no such thing, and, if it did, the Constitution would not permit it.”

The outcome was unexpected in that the court had allowed the challenged Alabama map to be used for the 2022 elections, and in arguments last October the justices appeared willing to make it harder to challenge redistricting plans as racially discriminatory under the Voting Rights Act of 1965.

Alabama Republican Party Chairman John Wahl said in a statement that state lawmakers would comply with the ruling.

“Regardless of our disagreement with the Court’s decision, we are confident the Alabama Legislature will redraw district lines that ensure the people of Alabama are represented by members who share their beliefs, while following the requirements of applicable law,” Wahl said.

Louisiana’s congressional map had separately been identified as probably discriminatory by a lower court.

That map, too, remained in effect last year and now will have to be redrawn.

The National Redistricting Foundation said in a statement that its pending lawsuits in Georgia and Texas also could be affected.

With Post wires