SAN FRANCISCO -- California's highest court decided Wednesday to wade back into the legal morass surrounding the state's voter-approved gay marriage ban, agreeing to rule on a question of state law considered crucial to the survival of Proposition 8.

The California Supreme Court accepted without comment a formal inquiry from a federal appeals court that's mulling the constitutionality of the 2008 ban that was struck down in August as a violation of gay Californians' civil rights.

The three-judge panel of the 9th U.S. Circuit Court of Appeals said last month it can't reach a decision until it knows if ballot proposition sponsors have legal standing to step in when the attorney general and governor refuse to defend voter-approved initiatives in court.

The question is pivotal to the future of Proposition 8 because former Gov. Arnold Schwarzenegger and Gov. Jerry Brown in his previous role as attorney general both declined to appeal the decision to overturn Proposition 8.

The measure's sponsors, a coalition of religious and conservative groups called Protect Marriage, are trying to fill that void. But the 9th Circuit said it is unclear if the coalition has authority to do so under either federal or state law.

Without further guidance from the state court, the federal panel said it would have to dismiss the appeal and the ruling that Proposition 8 is unconstitutional would stand.

John Matsusaka, president of the Initiative and Referendum Institute at the University of Southern California, said the state court did the proper thing by taking up the question.

"As a matter of law, it's right that you want to give these groups standing," he said. "The attorney general and governor should have done their job and not put us into a constitutional bind."

Lawyers for the two gay couples who successfully sued to overturn the ban had urged the state Supreme Court to refuse the case, arguing the issue of who is eligible to bring an appeal in federal court is a matter of federal law.

The U.S. Supreme Court, in a non-binding decision, has cast doubt on the ability of initiative backers to appeal rulings.

Lawyers for Protect Marriage had urged the state court to get involved, maintaining it would be a disaster for democracy if laws enacted by citizens could be tossed out because state leaders chose not to defend them.

The state Supreme Court asked to be briefed on the question this spring and said it would be prepared to hear oral arguments as soon as September. Same-sex marriage supporters expressed disappointment at the timeline and hope the court could be persuaded to move more quickly.

"More than six months ago, the federal district court declared unequivocally that Prop. 8 is unconstitutional and that it causes grave harm to gay and lesbian couples and their families each day that it is in effect," Chad Griffin, president of the foundation that funded the couples' lawsuit, said.

Meanwhile, a California lawmaker has introduced a bill requiring the state attorney general to defend all voter-approved laws from legal challenges and authorizing the sponsors of ballot propositions to step in if he or she won't or can't act.

The bill by Orange County Republican Sen. Tom Harman also would permit the attorney general to appoint a special counsel to defend an initiative if the sponsors choose not to.