(CNN) -- California's highest court on Tuesday appeared to support the right of official opponents of gay marriage to defend Proposition 8, the 2008 initiative defining marriage as only between one man and one woman.
Top state officials -- including former attorney general and current Gov. Jerry Brown -- have refused to back the voter-approved measure in court, setting up an unresolved fight over the so-called "gateway" legal issue. The state's prior governor, Republican Arnold Schwarzenegger, had also declined to defend Prop 8.
At issue: If the state will not intervene, can private groups and individuals step in and defend citizen initiatives?
"You want the federal courts to answer this question with only one side represented?" asked a skeptical Justice Ming Chin of same-sex marriage supporters.
A federal judge ruled last year the ban on allowing gay people to marry was unconstitutional.
The standing dispute has put on hold the larger legal fight over the constitutionality of California's same-sex marriage ban, and whether it discriminates against gay men and lesbians.
The federal 9th Circuit Court of Appeals had been considering a civil rights lawsuit from opponents of Prop 8 when the standing issue was first raised. That court in January asked the California Supreme Court to tackle the narrow, but key, question.
The conservative group ProtectMarriage.com has been leading the legal fight to defend the initiative.
During the hourlong arguments in San Francisco, several state justices wondered whether the ballot initiative system in California -- which the court had earlier said was valid -- would be meaningless if no one were allowed to defend it, absent state involvement.
"If we agree with your position, it would appear to me that we would nullify the great power the people have reserved for themselves" to approve ballot initiatives, said an animated Justice Joyce Kennard to the lawyer representing same-sex couples.
And Chief Justice Tani Cantil-Sakauye said, "What happens to the state's interest (when state officials will not defend an initiative)? Does it evaporate?"
Charles Cooper, attorney for the ballot sponsors, said California specifically allows voters to directly enact this kind of legislation, and that its official sponsors should be allowed to step in when the state refuses to defend such measures. But he was pressed hard by several justices over whether Prop 8 proponents could ultimately prove actual injury if same-sex marriages were allowed to resume in the state.
However, Theodore Olson, a former solicitor general in the Bush administration and a leading conservative lawyer, said only state officials can defend state laws. He is defending a coalition of same-sex couples and several civil rights groups.
"There is ample authority that individuals do not have a right to defend a law unless they would suffer a direct and immediate harm from its invalidation," Olson said. "The proponents of Proposition 8 will not suffer any harm from a decision that grants gay and lesbian Californians their fundamental civil right to marry."
The brisk arguments were televised over the state's calchannel.com public affairs cable network.
An active questioner was the state high court's newest member, Justice Goodwin Liu, who joined the bench just last week. He had been rejected earlier this year for a seat on the federal appeals court also hearing the gay marriage case.
Liu was then named to the state court by Gov. Brown. He too seemed supportive of the idea the California Constitution gives even private sponsors of ballot measures the right to defend them in court.
The California Supreme Court will rule on the issue within 90 days.
If the state high court fails to provide any guidance to the 9th Circuit, the federal court could decide on its own either to grant or refuse standing to the private parties. Top state officials -- including the governor -- may also have the discretion to allow other individuals to defend Proposition 8 in court. But Brown so far has refused to extend that authority.
Depending on how the state court rules, the federal appeals court may then have wide discretion to either dismiss Prop 8, leave the statute intact or put off a final decision on the larger question of the constitutionality of same-sex marriage. The three-judge federal appeals panel heard oral arguments in December on the civil rights aspect.
The U.S. Supreme Court may ultimately be asked to resolve the constitutional issue of gay marriage.
In a letter last week to rally Prop 8 supporters, Andy Pungo, a lawyer for the Protect Marriage coalition, said, "This is a pivotal hearing for us as we continue to fight to uphold the People's vote to restore traditional marriage in California against these ferocious attacks. We simply cannot allow our opponents to manipulate the legal system to the point where there is nobody left to defend the People!"
The case has had an up-and-down series of rulings and referendums. The state's high court had allowed same-sex marriage, but then the voter referendum preventing it passed three years ago with 52% of the vote. The California Supreme Court subsequently allowed that initiative to stand, saying it represented the will of the people.
Opponents of the law next filed a federal challenge, saying it violated 14th Amendment constitutional protections of due process and equal protection.
U.S. District Court Judge Vaughn Walker on August 4, 2010 agreed, issuing a 136-page opinion that concluded, "Proposition 8 fails to advance any rational basis in singling out gay men and lesbians for denial of a marriage license."
The judge, appointed by President George H.W. Bush, added, "Proposition 8 does nothing more than enshrine in the California Constitution the notion that opposite-sex couples are superior to same-sex couples."
Walker has since retired from the bench, and announced he is gay and in a committed relationship. That raised questions from many marriage opponents about whether he should have heard the case.
Same-sex marriage is currently legal in six states and in the District of Columbia, while civil unions are permitted in New Jersey. The six states are Massachusetts, Connecticut, Vermont, Iowa, New York and New Hampshire.
The federal case is Perry v. Brown (10-16696). The state case is Perry v. Brown (S189476).