The justices did not rule on the merits of the case or same-sex marriage bans in general, leaving both sides confident they'll ultimately win. The high court's decision stays in effect while the Denver-based 10th U.S. Circuit Court of Appeals considers the long-term question of whether gay couples have a right to wed in Utah.
For those couples who just got married - or were planning their nuptials - the latest twist in the legal battle clouds what was seen as a cause for celebration.
"It feels like we are second-class citizens during the stay," said Moudi Sbeity, who is waiting to get married until the legal process plays out. "There's also the fear of the unknown of what might come next."
Sbeity and partner Derek Kitchen are one of the three couples who brought the Utah lawsuit that led to the surprise Dec. 20 ruling by U.S. District Judge Robert Shelby, who said the state's ban on same-sex marriage violated gay and lesbian couples' constitutional rights.
State officials praised the decision, saying it should have come earlier to avoid uncertainty. 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," Gov. Gary Herbert said.
Now the state is trying to determine whether the marriages that have already taken place are still valid, Utah Attorney General Sean Reyes said. He said he didn't know when they'd make a determination, saying they don't want to rush an important legal decision.
"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 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 matches up directly with Utah's unique situation, which adds to the uncertainty about whether the marriages will remain valid or be void, said Douglas NeJaime, a professor of law at the University of California, Irvine. Marriage licenses issued in 2008 in California prior to 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.
"Neither situation is completely analogous," NeJaime said.
That leads NeJaime to believe a court will need to rule on Utah's marriages. If the Utah attorney general challenges the validity of the licenses as expected, that might lead to several months of limbo for the couples, he said.
For 17 days, Utah was the 18th state to allow gay couples to wed.
More than a thousand couples flocked to county clerks offices, marrying on courthouse steps in darkness and celebrating a judge's decision that the 2004 voter-approved ban on same-sex marriage in the state was unconstitutional. The state appealed to the 10th Circuit, which also refused to halt marriages in the meantime.
It was a surprising development in a state where nearly two-thirds of the 2.8 million residents are members of The Church of Jesus Christ of Latter-day Saints, and Mormons dominate the state's legal and political circles. The Mormon church was one of the leading forces behind California's short-lived ban on same-sex marriage, Proposition 8.
Though the church has softened its stance toward gays and lesbians in recent years, it still teaches that homosexual activity is a sin and stands by its support for "traditional marriage." Church officials say they hope a higher court validates its belief that marriage is between a man and woman.
Shelby's ruling overturning the state's ban was the first by a federal judge to overturn a state marriage ban since the U.S. Supreme Court issued two decisions on same-sex marriage in June.
The justices at that time struck down a provision of the federal Defense of Marriage Act that prevented legally married gay and lesbian couples from receiving a range of tax, health, pension and other federal benefits.
Shelby cited the decision in his ruling that the state failed to show that allowing same-sex marriages would affect opposite-sex marriages in any way.
"In the absence of such evidence, the State's unsupported fears and speculations are insufficient to justify the State's refusal to dignify the family relationships of its gay and lesbian citizens," Shelby wrote.
On the same day, the court left in place a trial court's decision that struck down California's constitutional ban on same-sex marriage. That decision paved the way for same-sex unions to resume in California.
California is among 17 states and the District of Columbia that allow, or soon will allow, gay and lesbian couples to wed.
The others are: Connecticut, Delaware, Hawaii, Illinois, Iowa, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, New Mexico, New York, Rhode Island, Vermont and Washington state. Utah was the 18th.
The action now shifts to Denver, where the appeals court will consider arguments from the state against same-sex marriage as well as from the three gay and lesbian couples who challenged the ban in support of Shelby's ruling. Shelby and the appeals court had previously rebuffed the state's plea to stop gay weddings pending appeal.
The 10th Circuit has set short deadlines for both sides to file their written arguments, with the state's first brief due on January 27. No date for argument has been set yet.
James Magleby, a lawyer for couples who sued to overturn the ban, said that while the halt to same-sex marriages is temporary - assuming the appeals court does not reverse Shelby's ruling - it is disappointing because it leaves Utah families waiting to marry until the appeal is over.
"Every day that goes by, same-sex couples and their children are being harmed by not being able to marry and be treated equally," Magleby said in a statement that also proclaimed confidence in his side's case before the appellate judges.