The Supreme Court building in Washington, D.C. (Andrew Harrer/BLOOMBERG)

The Supreme Court on Friday set aside court-drawn redistricting plans for Texas that were favored by minorities and Democrats, saying the lower court “exceeded its mission” by not deferring to maps drawn by the state legislature.

In an unsigned opinion that drew no dissents, the justices said a legislature’s reapportionment plan should be the “starting point” for judges who are called upon to draw maps when there are constitutional challenges. The plan by the Republican-dominated Texas legislature is the subject of lawsuits from organizations representing the minority groups that make up about three-quarters of the state’s population boom.

The population growth means Texas will have four additional seats in Congress, and some political analysts say the redistricting maps are critical because they could help decide which party controls the House of Representatives.

The Supreme Court’s opinion was the first round in a series of looming challenges in which the justices are likely to be asked to referee battles over redistricting, the application of the Voting Rights Act of 1964 and the Obama administration’s vow to police voter law changes enacted by Republican-dominated state legislatures.

Just hours after the Texas ruling, the justices stayed a lower court decision that struck down West Virginia’s congressional redistricting plan because the judges said it deviated too much from the “one-person, one-vote” standard.

“In every decade since the 1960s, the court has stepped up its role in regulating the elections process,” said Heather Gerken, an election law expert at Yale Law School who is advising President Obama’s reelection effort.

Friday’s decision was a modest one, she said. “But my feeling is this begins with a whimper and ends with a bang.”

The ruling, which came 11 days after the court heard arguments, sent the case back to a three-judge panel in San Antonio.

“A district court should take guidance from the state’s recently enacted plan in drafting an interim plan,” the justices wrote. At the same time, they said, the court must be careful not to incorporate parts of a state’s plan that might violate the Constitution and Voting Rights Act.

The ruling was nuanced enough that both sides found reason to claim victory.

“The Supreme Court confirmed that the San Antonio court drew illegal maps, without regard for the policy decisions of elected leaders,” Texas Attorney General Greg Abbott said in a statement. “As the justices point out, courts are ill-suited to make policy judgments and redistricting is primarily the responsibility of the state.”

But Pamela Karlan, a constitutional law expert at Stanford University who is representing challengers to the Texas plan, said the ruling simply requires lower court judges to be more clear about the decisions they make.

She compared the court’s decision with a schoolteacher telling a student, “You got the right answer, but you didn’t show enough of your work.”

Because of its population growth over the past decade, Texas was awarded four new congressional districts, bringing its total to 36. Nearly two-thirds of that growth was in the Hispanic community, and Latino groups said the plans approved by Texas’s legislature and signed by Gov. Rick Perry (R) improperly diluted their power.

Political analysts said the legislature’s plan could result in Republicans claiming three of the new districts. The plan by the three-judge panel in San Antonio could result in just the opposite, they said.

The Supreme Court’s mission was complicated by the fact that Texas’s redistricting was being considered in two courts with different objectives.

Because of past discrimination against minorities, Texas is one of the states covered by Section 5 of the Voting Rights Act, meaning its electoral laws must be “pre-cleared” — approved by the Justice Department or a panel of federal judges in Washington.

Texas chose to go the judicial route, and a three-judge panel in Washington this week held a trial to consider the Section 5 challenges. It is not expected to rule until next month.

Until that is settled, the San Antonio judges were charged with drawing an interim map, so that Texas’s elections could proceed.

Texas has delayed its primaries, which are among the earliest in the nation, because of the dispute. The state says it needs a new plan by Feb. 1 to hold primary elections on its new date, April 3.

Texas last month asked the Supreme Court to keep the judicial plan from being used even on an interim basis, and that was the request granted Friday.

The court’s order noted the difficulties facing the San Antonio judges. The plan passed by the legislature cannot be used, the justices agreed, because it has not been pre-cleared.

“But that does not mean that the plan is of no account or that the policy judgments it reflects can be disregarded by a district court drawing an interim plan,” the justices wrote.

The court was especially critical of the San Antonio judges for drawing a congressional district that appeared to be a “minority coalition” district. The justices said it was unclear whether the district was intentionally drawn to allow two different minority groups to band together to form a majority.

But, “if the district court did set out to create a minority coalition district, rather than drawing a district that simply reflected population growth, it had no basis for doing so,” the order said.

New York University School of Law professor Richard Pildes said it is far from clear which plan will be used in the Texas elections. “I think we’re only at the beginning stages of sorting this out,” he said.

While the constitutionality of Section 5’s pre-clearance requirement was not at issue in the case, Justice Clarence Thomas wrote separately to reiterate his opinion that it should not stand. No other justice joined him, although the ruling did note that the court in a 2009 case from Texas said Section 5 raised “serious constitutional questions” because of its intrusion on state sovereignty.

The challenges to the plan are collectively known as Perry v. Perez.