The Wisconsin Supreme Court said on Friday that the state’s heavily gerrymandered legislative maps that favor Republicans are unconstitutional. It ordered new maps before the 2024 election in a ruling that could produce a seismic political shift in a crucial presidential swing state.

Justice Jill J. Karofsky, writing for the majority, said that Wisconsin’s current maps violate a requirement in the State Constitution “that Wisconsin’s state legislative districts must be composed of physically adjoining territory.”

“Given the language in the Constitution, the question before us is straightforward,” she wrote. “When legislative districts are composed of separate, detached parts, do they consist of ‘contiguous territory’? We conclude that they do not.”

The decision was widely expected from a court that flipped to a 4-to-3 liberal majority this year after the most expensive judicial election in U.S. history. The winner of that election, Justice Janet Protasiewicz, a former Milwaukee County judge, was openly critical of the current legislative maps, calling them “rigged” and “unfair” during her campaign.