There are other same-sex marriage cases in the pipeline, including ones from federal appeals courts striking down bans in Oklahoma and Virginia. The Supreme Court could agree to hear one or more of the several cases, or none of them.

Most of the usual signs suggest the court will step in. It is no small thing for a lower federal court to strike down a state law or a provision of a state Constitution, and that alone may warrant review. The Supreme Court has indicated its interest in developments in Utah by twice issuing stays that blocked lower court rulings that would have allowed gay marriages to proceed or be recognized. And it cannot hurt that both sides in the Utah case agree the case should be heard.

All that is missing from the standard criteria for Supreme Court review is disagreement in the lower courts, which have unanimously ruled against same-sex marriage bans in the last year. A set of cases heard Wednesday by the United States Court of Appeals for the Sixth Circuit, in Cincinnati, may soon supply that last element. Two other federal appeals courts are also scheduled to hear appeals in the coming weeks.

The Utah ruling came from the United States Court of Appeals for the 10th Circuit, in Denver. It said an amendment to the Utah Constitution defining marriage as the union of a man and a woman denied gay couples the fundamental right to marry under the federal Constitution.

In urging the Supreme Court to hear the case, Utah officials said the ruling had deprived the state’s voters, who adopted the ban in a 2004 referendum, of a different fundamental right, one allowing them to “act through a lawful electoral process.”

“A vast cloud covers this entire area of the law, and only this court can lift it,” the brief said. “This case provides an ideal vehicle to do just that.”

Here, too, Ms. Tomsic said she agreed with her adversaries that uncertainty over same-sex marriage is intolerable. “We are one country,” she said. “Even if you are in a state that recognizes same-sex marriage, you are at risk if you travel or move.”

She added it is fitting that the first in the current wave of same-sex marriage cases comes from Utah. “If it can happen in Utah, it can happen anywhere,” she said. “We are a very conservative state.”