A three-judge panel in North Carolina has ordered the state not to use the current congressional districts for the 2020 elections while the lawsuit against them proceeds. 

The preliminary injunction could delay the state’s March 3 congressional primaries, setting up a potentially messy primary season in a politically competitive state up and down the ballot in 2020.

The state court heard arguments that the map crafted by the Republican-led legislature was an illegal partisan gerrymander last Thursday, when the State Board of Elections endorsed the idea of an injunction.

The plaintiffs who filed suit against the maps in state court on Sept. 27 include Democratic and unaffiliated voters, as well as the national redistricting group connected to former President Barack Obama’s Attorney General, Eric Holder. Republican defendants have argued that it’s too close to the December candidate filing deadline to have a new map. 

North Carolina’s congressional delegation includes 10 Republicans and three Democrats. Republicans narrowly held onto the 9th District in a hotly contested special election last month. 

GOP Rep. George Holding, who defeated former Rep. Renee Ellmers when they were drawn into the same district in 2016, told the Raleigh News & Observer earlier this month that he hasn’t been raising much money locally because he expects the state will be forced to draw new lines. 

A federal court had previously ruled that the state racially gerrymandered its congressional districts after the 2010 Census. In response, the legislature drew new maps for the 2016 congressional primaries that retained the GOP’s partisan advantage in the House delegation.

Federal courts struck it down as a partisan gerrymander, but the Supreme Court ruled earlier this year that federal courts do not have jurisdiction over political gerrymandering. That ruling left open the option of challenges under state constitutions, which were pursued by opponents of the North Carolina map.

A bipartisan panel of state judges has already struck down the state’s legislative maps as unconstitutional. In that decision, the court mentioned the late Republican redistricting strategist Thomas Hofeller, whom Democrats have argued set out to draw maps that maximized the GOP advantage in the state. The court said he “targeted” Democratic voters based on their voting history. Plaintiffs in the congressional district case have partially relied on documents from Hofeller, too.

The three-judge panel on Monday said that it reserves the right to move the date of all of the state’s 2020 primaries, not just the congressional primaries.

Michael Macagnone contributed to this report.