North Carolina’s congressional map can’t be used in 2020 because it’s so severely gerrymandered, a panel of three state judges ruled on Monday. The judges said the gerrymandering, which benefits Republicans in the state, was so severe that it ran afoul of the state’s constitution.

The ruling, a preliminary injunction, is a victory for advocacy groups, and blocks the state from using its current plan in 2020. Republicans drew the map in 2016 and openly talked about the advantage it gave to Republicans. The GOP controls 10 of the state’s 13 congressional seats.

The judicial panel cited the state constitution’s guarantee of free elections, equal protection under the law and freedom of speech and assembly.

“Extreme partisan gerrymandering ― namely redistricting plans that entrench politicians in power, that evince a fundamental distrust of voters by serving the self-interest of political parties over the public good, and that dilute and devalue votes of some citizens compared to others ― is contrary to the fundamental right of North Carolina citizens to have elections conducted freely and honestly to ascertain, fairly and truthfully, the will of the people,” the panel wrote.

The ruling comes after the same three-judge panel struck down the state’s map for legislative districts in September, saying they too violated the state’s constitution.

The ruling is a particularly significant victory for anti-gerrymandering advocates because they had tried to have the same districts struck down in federal court. A lower court struck the districts down, but in June, the U.S. Supreme Court ruled on a case involving the very same districts, saying partisan gerrymandering was a question beyond the reach of the federal courts.

Despite that decision, the five-justice majority at the Supreme Court said that state courts and state constitutions may be able to act against gerrymandering. Advocates now believe that bringing suits in state court may be the most effective legal strategy for combatting gerrymandering. The two gerrymandering victories in state court bolsters that theory.

The districts blocked on Monday were obviously and severely drawn to favor Republican candidates. When Republicans drew the districts in 2016, one of the explicit criteria for the plan was that it had to produce a map that gave Republicans a 10-3 advantage in the congressional delegation. State Rep. David Lewis (R), one of the chairs of the redistricting committee, said he wanted to draw a map with that 10-3 advantage because he did not think it was possible to draw one that gave Republicans an 11-2 advantage.

North Carolina’s primary elections are set for March, and the candidate filing period begins Dec. 2. Though the court said it would try to quickly resolve the case to avoid confusion, it urged the state legislature, where Republicans still have a majority, to come up with new districts.

Read the ruling below: