WASHINGTON — The Supreme Court on Monday blocked further same-sex marriages in Utah while state officials appeal a decision allowing such unions.
The terse order, from the full court, issued a stay “pending final disposition” of an appeal to the federal appeals court in Denver. It offered no reasoning.
The Supreme Court acted more than two weeks after a federal judge in Salt Lake City on Dec. 20 struck down Utah’s ban on same-sex marriage, saying it violated principles of equal protection and due process. Judge Robert J. Shelby of US District Court refused to stay his decision while it was appealed, as did the US Court of Appeals for the 10th Circuit, in Denver.
Shelby’s decision made Utah the 18th state, along with the District of Columbia, to allow same-sex marriages, and many hundreds of gay and lesbian couples have married there in the intervening weeks.
Should a higher court ultimately reverse Shelby’s ruling, it is not clear what would happen to those marriages.
In their Supreme Court brief, Utah officials said Shelby’s decision should be stayed “to minimize the enormous disruption to the state and its citizens of potentially having to ‘unwind’ thousands of same-sex marriages.”
The brief did not explain why it took officials so long to ask the Supreme Court for a stay; they filed on Dec. 31, a week after the appeals court declined to issue one.
Shelby was only the second federal judge to strike down a state ban on same-sex marriages, along with Judge Vaughn R. Walker in San Francisco, who in 2010 struck down Proposition 8, California’s ban. That ruling was stayed while it was considered by an appeals court, which affirmed it.
In June, the Supreme Court effectively sustained Walker’s decision on technical grounds and without reaching the question of whether there is a constitutional right to same-sex marriage.
Other states have allowed same-sex marriages as a result of ballot measures, legislative action, or decisions from state courts. Utah’s ban, an amendment to the state Constitution, was passed in 2004 with the support of 66 percent of the voters.
With the Utah decision stayed, 17 states and the District of Columbia allow, or soon will allow, gay and lesbian couples to wed. The states are: California, Connecticut, Delaware, Hawaii, Illinois, Iowa, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, New Mexico, New York, Rhode Island, Vermont, and Washington.
In urging the Supreme Court to stay Shelby’s decision, Utah officials relied on the second same-sex marriage decision issued by the Supreme Court in June, United States v. Windsor, though the officials conceded that the ruling offered support to both sides in their case.
The Windsor decision struck down the part of the Defense of Marriage Act that denied federal benefits to married same-sex couples in states that allowed such unions. Justice Anthony M. Kennedy, writing for a five-justice majority, grounded his decision partly in federalism principles, saying the regulation of marriage was primarily a matter for the states.
Utah’s brief relied on that part of the Windsor ruling, saying it supported the right of voters in Utah to define who was entitled to marry in the state. But the brief also acknowledged that Kennedy had expressed concern about the harm caused to the children of gay and lesbian couples by laws that demean them.
On Monday, Utah officials praised the high court’s ruling, saying it should have come earlier to avoid uncertainty, the Associated Press reported. Two previous courts turned down their request for a stay.
‘‘Clearly, the stay should have been granted with the original District Court decision in order to have avoided the uncertainty created by this unprecedented change,’’ Governor Gary Herbert said.
Now the state is trying to determine whether the marriages that have taken place are still valid, Attorney General Sean Reyes of Utah said.
‘‘This is precisely the uncertainty we were hoping to avoid by requesting the stay,’’ Reyes said. ‘‘It’s unfortunate that many Utah citizens have been put into this legal limbo.’’
The Supreme Court’s unsigned order did not indicate whether anyone dissented from the decision to halt same-sex marriages in Utah. Justice Sonia Sotomayor, who handles emergency appeals from Utah and the five other states in the 10th Circuit, turned the matter over to the entire court.
There is no precedent that directly matches Utah’s situation, which adds to the uncertainty about whether the marriages will remain valid or be void.
Marriage licenses issued in 2008 in California before the passage of the state’s same-sex marriage ban were eventually upheld by the state supreme court, but marriages done in San Francisco in 2004 were invalidated.