Appeal filed over gay marriage ruling in Calif.

SAN FRANCISCO — Supporters of California's gay marriage ban filed an appeal of a federal judge's ruling striking down the voter-approved law.

The appeal filed late Wednesday to the 9th U.S. Circuit Court of Appeals was expected, as lawyers on both sides of the legal battle repeatedly vowed to carry the fight to a higher court if they lost.

Earlier in the day, a federal judge in San Francisco overturned California's Proposition 8, which restricts a marriage to one man and one woman. U.S. District Court Judge Vaughn Walker ruled the law violates federal equal protections and due process laws.

The 9th Circuit court has no deadlines to hear the case, which will be randomly assigned to a three-judge panel. It's expected that the panel will order both sides to submit written legal arguments before scheduling a hearing.

The outcome in the appeals court could force the U.S. Supreme Court to confront the question of whether gays have a constitutional right to wed.

"This ruling, if allowed to stand, threatens not only Prop 8 in California but the laws in 45 other states that define marriage as one man and one woman," said Brian Brown, president of the National Organization for Marriage, which helped fund the 2008 campaign that led to the ban's passage.

Currently, same-sex couples can legally wed only in Massachusetts, Iowa, Connecticut, Vermont, New Hampshire and Washington, D.C.

The appeal was filed by Protect Marriage, a coalition of religious and conservative groups that sponsored Proposition 8 and wound up defending it after California Gov. Arnold Schwarzenegger and Attorney General Jerry Brown refused.

Walker, meanwhile, said he would consider waiting for the 9th Circuit to render its decision before he makes his opinion final and requires the state to stop enforcing the ban. The judge ordered both sides to submit written arguments by Friday on the issue.

Hundreds of same-sex marriage supporters celebrated the verdict at public gatherings in San Francisco, West Hollywood and New York City, while acknowledging they have watched court victories evaporate before.

California voters passed Proposition 8 five months after the state Supreme Court legalized same-sex unions and an estimated 18,000 same-sex couples already had tied the knot.

Joe Briggs, 32, an actor who attended a West Hollywood gathering, said he was thrilled to hear about the ruling but was curbing his enthusiasm because of the legal fight still ahead.