Alabama’s Republican-backed congressional map illegally dilutes black residents’ voting power and must be redrawn, a panel of federal judges ruled on Tuesday, boosting Democrats’ chances to win back a US House majority in the 2024 election.

The ruling is the second time the court has thrown out a congressional plan enacted by the Republican-controlled state legislature, and the three-judge panel in Birmingham wrote that it saw little reason to give lawmakers a third chance. Instead, a court-appointed special master will be tasked with creating a new map ahead of next year’s vote.

“We have now said twice that this Voting Rights Act case is not close,” the judges wrote. “And we are deeply troubled that the State enacted a map that the State readily admits does not provide the remedy we said federal law requires.”

Under the Republican map, only one of the state’s seven congressional districts is majority black, even though black residents make up more than a quarter of the state’s population.

The panel first intervened in 2022, ruling that an earlier Republican plan was illegal. After the US Supreme Court upheld the panel’s decision in June, the Birmingham court ordered Alabama legislators to create a second district with either a black majority or “something quite close” to comply with the Voting Rights Act. The law bars lawmakers from drawing district lines in a manner that discriminates against minority voters.

The latest plan increased the number of black voters in a second district but fell far short of a majority, prompting civil rights groups to challenge the new map.