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.

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.

The appeal was filed by Protect Marriage, a coalition of religious and conservative groups that sponsored Proposition 8.

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.