(CNN)A federal court ordered Michigan to redraw its congressional and state legislative districts Thursday, raising the possibility that the state's Republican-drawn maps could be tossed ahead of the 2020 election.
Federal court strikes down several redistricting plans for Michigan
But similar battles over legislative maps in Maryland and North Carolina are already before the Supreme Court, and appear likely to instead determine how the Michigan case will proceed.
A panel of federal judges on Thursday ruled that many of Michigan's districts -- including nine of its 14 congressional districts, two of which were previously held by Republicans but picked off by Democrats in last year's midterm elections -- were unconstitutionally gerrymandered to favor the GOP. The challenge was brought by the League of Women Voters of Michigan and several individual voters.
The court held the plans violated the plaintiffs' 14th Amendment equal protection rights and the First Amendment. The suit was brought against Jocelyn Benson, the Democratic Michigan secretary of state.
"Today, this Court joins the growing chorus of federal courts that have, in recent years, held that partisan gerrymandering is unconstitutional," the panel of three judges held. They added that federal courts "must not abdicate their responsibility to protect American voters from this unconstitutional and pernicious practice that undermines our democracy."
But it's not clear if the legislative maps in the Great Lakes State will actually be redrawn, given that the Supreme Court is considering two other partisan gerrymander cases out of North Carolina and Maryland.
Election law expert Rick Hasen, of the University of California Irvine, said on a blog post that it "seems likely" that the Michigan decision could be stayed pending the outcome of the Supreme Court cases.
He said that the Michigan court based its ruling both on an equal protection and First Amendment theory, "the two main theories the Supreme Court is considering in the pending partisan gerrymandering cases out of North Carolina and Maryland."
If it stands, the ruling would be a huge boost to Democrats' chances of winning a "trifecta" -- control of the governorship and both chambers of the state Legislature -- for the first time in decades in a state that has traditionally favored the party.
The court's ruling would require special elections for the state Senate in 2020, rather than 2022, when they would otherwise be held. Moving those contests into the same cycle as the presidential election would almost certainly boost Democrats' chances of shifting the makeup of the chamber, where Republicans hold 22 seats to Democrats' 16, in their favor.
The national organization that steers Democratic investments in state legislative contests vowed Thursday to make Michigan a priority in 2020.
"The Democratic Legislative Campaign Committee is committed to flipping Michigan's Legislature and giving Governor Gretchen Whitmer the partners she needs to improve education and fix the state's infrastructure," executive director Jessica Post said in a statement.
Thursday's decision will be appealed, state Senate Republican leaders told Michigan news outlets.
The redistricting plans in Michigan affected by the ruling comprise those for nine congressional districts, seven state Senate districts and 11 state House districts.
"The Court concludes that the Enacted Plan was designed with the predominant purpose of advantaging Republicans and discriminating against Democrats," the judges wrote. "The Court further finds that the Enacted Plan achieved its intended effects because it discriminated against Democratic voters in numerous elections across multiple election cycles. Therefore, the Enacted Plan constitutes a durable partisan gerrymander."