A three-judge panel on Thursday ruled that Michigan must use new congressional and legislative maps in 2020, potentially setting up a more favorable battlefield for House Democrats, who flipped two seats in the state last fall. 

The federal court invalidated portions of the existing maps, drawn by the GOP-controlled legislature in 2011, pointing to an unconstitutional partisan gerrymander that violates the First and Fourteenth Amendment rights of voters.

The League of Women Voters and some Democrats had challenged the state’s 162 legislative and congressional districts, but the final suit only targeted 34 of those districts. Michigan has 14 congressional districts. The plaintiffs challenged the 1st, 4th, 5th, 7th, 8th, 9th, 10th, 11th and 12th congressional districts.

After the 2018 midterms, Democrats now hold five of those nine seats, and the full delegation is evenly split between the two parties, 7-7. 

The court found that all nine of the challenged congressional districts are unconstitutional partisan gerrymanders “because they dilute the views of Democratic voters.” The court reached the same conclusion for seven state Senate districts and 11 state House districts. 

The state legislature has until Aug. 1 to draw new maps and have them signed into law by Democratic Gov. Gretchen Whitmer. The court will draw remedial maps itself if that doesn’t happen, or if the new maps fail to address the “constitutional harm” the court found. 

The Supreme Court heard oral arguments in two partisan gerrymandering cases last month and is expected to issue rulings at the end of June.