| SAN FRANCISCO
SAN FRANCISCO A federal judge on Wednesday struck down a California ban on same-sex marriages as unconstitutional, handing a key victory to gay rights advocates in a politically charged decision almost certain to reach the U.S. Supreme Court.
Legal scholars said the decision has wide implications for nearly 40 states with similar laws on their books, making it more difficult to defend those measures in court on the basis of moral grounds or social tradition.
Still, U.S. District Court Chief Judge Vaughn Walker ordered the voter-approved ban, known as Proposition 8, to remain in place at least temporarily until he decides on a request by supporters of the ban to keep it intact while the case moves to a higher court.
Although the result leaves gay men and lesbian couples unable to marry for now, Walker said Prop 8 opponents "demonstrated by overwhelming evidence" that it violates due process and equal-protection rights under the U.S. Constitution.
"Proposition 8 fails to advance any rational basis in singling out gay men and lesbians for denial of a marriage license," Walker wrote in the conclusion of his 136-page opinion.
Supporters of Prop 8, which California voters passed 52.5 percent to 47.5 percent in November 2008 after one of the most expensive ballot-measure campaigns in U.S. history, expressed confidence they would ultimately prevail.
"There aren't five votes on the Supreme Court for gay marriage," Maggie Gallagher, chair of the National Organization for Marriage, said of the high court's conservative 5-4 majority.
Outside the federal courthouse in San Francisco, a cheer went up among a group of about 70 same-sex marriage supporters carrying small U.S. flags, as a large rainbow-striped flag -- the symbol of the gay rights movement -- waved overhead.
California Governor Arnold Schwarzenegger, who has said he personally supports gay marriage but would abide by the will of voters and the courts, said the decision "affirms the full protections and safeguards I believe everyone deserves."
Even the White House weighed in with a brief statement saying that President Barack Obama "has spoken out in opposition to Proposition 8 because it is divisive and discriminatory."
The highly anticipated ruling marked a major turning point in an emotionally charged social debate that has sharply divided the American public and its political establishment.
Gay rights advocates and civil libertarians have cast the legal battle as a fight for equal rights, while opponents, including many religious conservatives, see same-sex marriage as a threat to the traditional family.
Both sides have said an appeal to the 9th U.S. Circuit Court of Appeals was certain regardless of the outcome on Wednesday. The case could then go to the Supreme Court, provided the high court's justices opted to hear it.
"I'm thrilled," gay marriage supporter Steven Ray Davis said at the courthouse. "We still have a long way to go."
The decision has no bearing on 18,000 gay and lesbian couples who were legally wed in California from June 2008 when a state Supreme Court ruling overturned an earlier ban and November 2008 when Prop 8 passed.
The case against Prop 8, a state constitutional amendment defining marriage as between a man and a woman, marks the first challenge in federal court to a state law barring same-sex matrimony.
Thirty-nine U.S. states have laws explicitly prohibiting gay marriage -- 30 adopted in their constitutions. Five states and the District of Columbia recognize gay marriage -- Iowa, Connecticut, New Hampshire, Vermont and Massachusetts.
Santa Clara University School of Law professor Margaret Russell said Walker's opinion, if sustained, would have broad consequences beyond California.
"Any marriage ban based on moral disapproval of gays would fall under that reasoning," she said.
Early last month, a federal judge in Massachusetts ruled that a 1996 federal law, the Defense of Marriage Act or DOMA, which denies federal recognition of same-sex marriages, even in states where it is allowed, was unconstitutional.
The federal government has 60 days to decide whether to appeal that ruling.
The two lead attorneys in the California case are Ted Olson and David Boies, who opposed each other in the landmark Supreme Court case that decided the outcome of the disputed 2000 U.S. presidential election and put George W. Bush in the White House.
Some gay rights advocates were initially hesitant to bring a federal challenge to Prop 8, fearing an eventual loss before the conservative-leaning U.S. Supreme Court.
(Additional reporting by Alexandria Sage, Dan Levine, Dan Whitcomb and Courtney Hoffman)
(Editing by Steve Gorman and Cynthia Osterman)