The U.S. Supreme Court on Wednesday delivered a devastating blow to one of America's most significant civil rights protections, ruling that Louisiana's congressional map violated the Constitution and fundamentally weakening the Voting Rights Act's ability to prevent racial discrimination in elections.

In a 6-3 decision in Louisiana v. Callais, the conservative-led court struck down a map that created two majority-Black congressional districts, holding that the state lacked sufficient legal justification to prioritize race when drawing electoral lines. The ruling is expected to unleash a wave of redistricting across Republican-controlled states in the South, potentially eliminating dozens of seats held by Black and Latino representatives in Congress.

The decision reinterprets Section 2 of the 1965 Voting Rights Act, a cornerstone of the Civil Rights Movement designed to protect minority voters from having their political power diluted through gerrymandering. Rather than allowing courts to examine whether maps have a discriminatory effect, the justices now require plaintiffs to prove states intentionally discriminated—a far more difficult legal standard.

"Under the Court's new view of Section 2, a State can, without legal consequence, systematically dilute minority citizens' voting power," Justice Elena Kagan wrote in dissent, joined by Justices Sonia Sotomayor and Ketanji Brown Jackson.

The case centered on a Louisiana map that Black voters and civil rights groups had fought for after the 2020 census. Following years of litigation, the state eventually agreed to create a second majority-Black district to reflect the state's 30 percent Black population. That compromise led Democratic Cleo Fields, a former member of Congress, to win election in 2024.

But white voters sued, claiming the map itself constituted unconstitutional racial gerrymandering. The Supreme Court sided with them, finding that because the Voting Rights Act did not require Louisiana to create a second majority-minority district, "none of the historical evidence presented by plaintiffs came close to showing an objective likelihood that the State's challenged map was the result of intentional racial discrimination."

The ruling immediately triggered redistricting efforts. Louisiana Gov. Jeff Landry announced the state would postpone its May primary elections to allow lawmakers to redraw the congressional map and eliminate the second majority-Black district. Florida lawmakers passed a new redistricting map hours after the decision that could secure Republicans up to four additional seats.

Democrats called for Congress to pass new voting rights legislation, but President Donald Trump would likely veto such measures. Some voting rights advocates urged more ambitious reforms, including expanding the Supreme Court itself.

An NPR analysis suggests up to 19 congressional seats held by Black Democrats could be at risk, potentially triggering the largest decline in Black representation in Congress since Reconstruction. At least 15 House districts from Louisiana eastward to North Carolina face potential elimination, according to experts.

The Court's majority opinion was written by Justice Samuel Alito and joined by Chief Justice John Roberts and Justices Clarence Thomas, Neil Gorsuch, Brett Kavanaugh and Amy Coney Barrett. The decision marks another chapter in a years-long assault on voting rights protections, following a 2013 Supreme Court decision that gutted the preclearance provision requiring certain states to obtain federal approval before changing voting rules.