SALT LAKE CITY -- A federal appeals court could rule any day now on the fate of same-sex marriage in Utah in a case that could either continue a nationwide momentum of gay and lesbian nuptials, or reverse it altogether.

The 10th U.S. Circuit Court of Appeals is expected to be the first federal appeals court to rule on same-sex marriage since the U.S. Supreme Court struck down portions of the federal Defense of Marriage Act last year.

Supporters and opponents of same-sex marriage are watching the 10th Circuit to see if it signals a change.

"This is really kind of where things start to count, because the district courts are just the first round and the appeals courts are supposed to give supervision," said Bill Duncan, the director of the Center for Family and Society with the conservative Sutherland Institute.

In recent months, federal judges in numerous states have overturned same-sex marriage bans. Others have legal challenges (only North Dakota is unchallenged right now).

It began with Utah on Dec. 20, 2013 when U.S. District Court Judge Robert Shelby overturned Amendment 3, which defined marriage as between a man and a woman and refused to recognize any other union. The state of Utah appealed it and the attorney general has said he is prepared to defend Amendment 3 to the U.S. Supreme Court, if necessary.

Arguments over the constitutionality of Amendment 3 were heard in Denver last month.

But since Amendment 3, other federal judges across the nation have struck down same-sex marriage bans.

Troy Booher, an attorney specializing in appeals with the firm Zimmerman Jones Booher, told FOX 13 that many judges ruling the same way may signal something to the appeals courts.

"It's difficult to ignore," he said. "It's also difficult to know what effect it has. It's clear that the tidal wave has an effect on judges, because every district court judge seems to be ruling the same way."

Clifford Rosky, the board chairman of the gay rights group Equality Utah, said it's hard to ignore all those judges.

"I cannot imagine that any federal judge would ignore the fact that 11 colleagues have unanimously agreed on a position of law," he told FOX 13.

Opponents of same-sex marriage note that the U.S. Supreme Court has the final word.

"It could be that the Supreme Court's going to say, 'Hey! Wait a second. You're going much further than we intended. We need to be the adult in the room and sort of pull you back,'" said Duncan.

What remains to be seen is if same-sex marriage will return to Utah. When it halted marriages in the state, the U.S. Supreme Court only said it was through the final disposition of the 10th Circuit Court of Appeals.

Read the U.S. Supreme Court's order here:

If the appeals court upholds Judge Shelby's decision and strikes down Amendment 3, Booher said "as a legal matter, the stay could expire." The U.S. Supreme Court would have to lift it, he said.

So far, the Utah Attorney General's Office has not filed any pre-emptive request to extend the stay if the court rules against the state.

Duncan said if the stay were to be lifted, "we'll just be in the exact same position as before." Rosky said he was not expecting marriages to resume anytime soon.

"I think it's quite clear the Supreme Court would grant another stay, but whether or not the attorney general asks for a stay, or whether or not the 10th Circuit just as a matter of prudence issues a temporary stay -- I think we'll see another stay," he said.

RELATED: Read the court filings in the Amendment 3 appeal