The U.S. 9th Circuit Court of Appeals' decision to deny an appeal of February's ruling against Proposition 8 paves the way for a U.S. Supreme Court decision on gay marriage by next year.
The decision means the U.S. Supreme Court is likely to have two major gay-rights cases on its docket in the near future. Another federal appeals court last week struck down a federal law that denied federal recognition to same-sex marriage.
Backers of Proposition 8 said they will ask the U.S. Supreme Court to review the 9th Circuit ruling.
Proposition 8, passed by California voters in November 2008, reinstated a ban on same-sex nuptials six months after the state Supreme Court had struck it down on state constitutional grounds. The ballot measure amended the state constitution. Two same-sex couples then sued in federal court, contending that Proposition 8 violated the U.S. Constitution.
A three-judge panel ruled 2-1 in February that the ban violated federal constitutional guarantees but limited the effect of the ruling to California. Sponsors of Proposition 8 asked the 9th Circuit to assemble an 11-judge panel to rehear the case.
A majority of the circuit's active judges voted against such reconsideration.
On Tuesday, Judge Diarmuid O'Scannlain, joined by two other jurists, wrote in a dissent that President Obama, in declaring his personal support for same-sex marriage, said it was a matter for states to decide.
"We have overruled the will of seven million California Proposition 8 voters," O'Scannlain wrote. "We should not have so roundly trumped California's democratic process without at least discussing this unparalleled decision as an en banc court."
Judges Stephen Reinhardt and Michael Daly Hawkins, who voted in February to overturn Proposition 8, responded in a concurring opinion that their ruling was narrow.
"We held only that under the particular circumstances relating to California's Proposition 8, that measure was invalid. In line with the rules governing judicial resolution of constitutional issues, we did not resolve the fundamental question that both sides asked us to: whether the Constitution prohibits the states from banning same-sex marriage.
"That question may be decided in the near future, but if so, it should be in some other case, at some other time."
The court's brief order Tuesday also said that Judge N.R. Smith, who dissented in the February ruling, favored review by an 11-member en banc panel of the court.
"The final chapter of the Proposition 8 case has now begun," said Chad Griffin, founder of a group that is financing the legal fight to overturn Proposition 8. "Should the United States Supreme Court decide to review the 9th Circuit's decision in our case, I am confident that the justices will stand on the side of fairness and equality."
Marriage Equality, another gay rights group, noted that opponents of gay marriage have 90 days to request review by the U.S. Supreme Court.
"Earlier this year, a three-judge panel of the 9th Circuit held that Proposition 8's targeting lesbian and gay people and taking away their freedom to marry violated the equality and fairness guarantees of the United States Constitution," said John Lewis, Marriage Equality USA's legal director.
"Today, a majority of the Court agreed, by declining to revisit the ruling. If the United States Supreme Court also declines to review the case, loving, committed lesbian and gay couples could be able to marry again in California later this year or early next year."