(CNN) The Supreme Court rejected on Wednesday a GOP request that it upend a congressional map adopted by the Wisconsin Supreme Court that was preferred by Democrats.
The justices gave no explanation for their decision not to intervene in the matter. That redistricting plan had a Republican lean but was still favored by Democrats because of the potential that it could give them at least one additional seat in the US House.
The Supreme Court, however, also on Wednesday issued an order in a separate Wisconsin redistricting case that blocked a state legislative map adopted by the Wisconsin Supreme Court that was backed by Democrats.
The US Supreme Court said that, in adopting the map, the Wisconsin Supreme Court had "committed legal error in its application of decisions of this Court regarding the relationship between the constitutional guarantee of equal protection and" the Voting Rights Act.
Justices Sonia Sotomayor -- in a dissent joined by Justice Elena Kagan -- called the move in the state legislative map case "unprecedented."
"This Court's intervention today is not only extraordinary but also unnecessary," she wrote.
The congressional map had been proposed by Democratic Gov. Tony Evers to the Wisconsin Supreme Court, which adopted it in a 4-3 ruling, after Evers and the legislature failed to come to an agreement on a new congressional plan.
The Supreme Court was asked by Republican members of the US House to toss that map. The Republicans accused the Wisconsin state Supreme Court of violating the US Constitution by allegedly changing midway through the litigation the standards the court would use to assess the maps proposed in the litigation.
"The Wisconsin Supreme Court's decision to hide the ball until after all parties had submitted maps clearly violates the Due Process Clause, under this Court's case law," the Republicans argued.
They also claimed that the map proposed by Evers violated Supreme Court precedent requiring that congressional districts be drawn with the equal numbers of people.
In its appeal to the US Supreme Court regarding the state legislative map, the GOP-legislature argued that the map adopted by the state supreme court was an unconstitutional racial gerrymander.
The map had been put forward by Evers, who asked the Supreme Court to leave the map the Wisconsin justices had chosen in place. Republican lawmakers, in their appeal, pointed specifically to how the governor's redistricting plan increased the number of majority-Black state assembly districts from six to seven.
The Republicans accused the Wisconsin Supreme Court of "maximizing" the number of majority-Black districts in the state plan, going beyond what was required by the Voting Rights Act and running afoul of the limits the US Constitution puts on the use of race, under US Supreme Court redistricting precedent.
On Wednesday, the US Supreme Court said in an unsigned order that its precedents for when race could be considered in redistricting had not been properly followed in the Wisconsin Supreme Court litigation. The US Supreme Court sent the case back to the Wisconsin court for another round of proceedings "not inconsistent with this opinion."
"On remand, the court is free to take additional evidence if it prefers to reconsider the Governor's maps rather than choose from among the other submissions. Any new analysis, however, must comply with our equal protection jurisprudence," the US Supreme Court's order said.
The US Supreme Court's latest move in the Wisconsin cases come after a mixed bag of rulings for Republicans. Alabama's GOP leaders secured an order last month from the five most conservative justices halting lower court rulings requiring that its congressional map be redrawn. The Supreme Court will hear that case -- in which Republicans are accused of diluting Black votes in violation of the Voting Rights Act -- in the coming months, with legal experts expecting the conservative court to further scale back the scope of the Voting Rights Act.
But Democrats scored two key victories in Pennsylvania and North Carolina cases that were appealed to the Supreme Court earlier this year. In those two cases, the US Supreme Court rejected GOP requests for intervention and left undisturbed Democratic-preferred maps that had been adopted by the state supreme courts in those states.