Gay marriage supporters learn the news that backers of Proposition 8 can defend their measure against gay marriage outside the California Supreme Court in San Francisco, Thursday, Nov. 17, 2011. (Eric Risberg/AP)

A California court cleared the way Thursday for federal appeals judges to render a highly anticipated decision on whether the state’s ban on same-sex marriage violates the U.S. Constitution.

The California Supreme Court ruled that proponents of the ban, known as Proposition 8, have the legal standing to defend it in court. The question had become crucial in the legal battle over the measure because state officials had declined to defend it.

A federal judge in August 2010 struck down the voter-approved same-sex marriage ban as unconstitutional, and proponents of Proposition 8 are seeking to appeal that ruling to the U.S. Court of Appeals for the 9th Circuit. The 9th Circuit, after hearing nationally televised arguments on the law’s constitutionality, took the unusual step in January of first asking the California Supreme Court to decide whether the proponents could legally pursue an appeal.

Lawyers involved in the case said the 9th Circuit is expected to agree that the proponents can appeal, meaning that the case will go forward and the federal judges will rule on the question at the heart of the dispute: Is Proposition 8 constitutional?

The case, which featured the nation’s first federal trial on same-sex marriage, is being closely watched by gay rights activists and legal observers. It comes amid a broader national debate over gay rights and is widely expected to end up at the U.S. Supreme Court.

In reacting to Thursday’s ruling, supporters and opponents of Proposition 8 reflected the strong passions surrounding the issue.

“We are delighted that the Supreme Court has clearly reaffirmed our right, as the official proponents of Proposition 8, to defend over 7­­ million Californians who amended their own state constitution to restore traditional marriage,’’ said Andy Pugno, general counsel for The California-based group, which supports traditional marriage, is expected to defend the ballot initiative in court.

Pugno added that the ruling “is an enormous boost for Proposition 8” and “a huge disaster for the homosexual marriage extremists.’’

Opponents expressed relief that the case could move forward and called on the 9th Circuit to uphold the lower court’s ruling and allow numerous same-sex couples to wed. The same-sex marriage ban remains in place while the appeal proceeds.

“The very important part of this is that it frees up the 9th Circuit to go ahead and decide the constitutional question,’’ said Theodore B. Olson, a former U.S. solicitor general who is representing Proposition 8 opponents. Olson, a longtime conservative luminary, formed an odd-couple partnership with liberal trial lawyer David Boies in taking on the ban.

“We are very hopeful for a relatively prompt 9th Circuit decision vindicating the rights of gay and lesbian citizens in California under the U.S. Constitution,’’ Olson said.