SACRAMENTO, Calif. (Legal Newsline)-When gay and lesbian couples in California begin lining up for marriage licenses in mid-June, it will be with the backing of state Attorney General Jerry Brown and Republican Gov. Arnold Schwarzenegger.

The state Supreme Court on Thursday overturned a 30-year-old law prohibiting same-sex marriage as well as a voter-approved initiative that defined marriage between a man and a woman.

Brown, acting as the state's top lawyer, argued against overturning the ban, but his spokesman said he'll enforce the ruling, and California hasn't joined other groups in asking for the court to stay the decision.

"We're going to back the governor," Brown spokesman Gareth Lacy told Legal Newsline.

This week's jubilation among gay rights activists could be short lived.

Conservative and some religious groups are already priming for November, promising a ballot initiative to amend the state's constitution defining marriage as between a man and a woman.

If the issue does end up on the ballot, it's likely to be a close vote. Recent polls show Californians are split over whether same-sex couples should be allowed to marry, though most surveys still come down with slightly more against.

Massachusetts is the only other state to have legalized same-sex marriages, and that, too, came from the courts.

Twenty-six states outlaw gay unions. Two years ago, Arizona voters turned down a law banning same-sex marriage, the only state to do so thus far.

The Campaign for Children and Families said the California justices' divided ruling "has destroyed the civil institution of marriage between a man and a woman," and said the ruling will be "short-lived," said CCF president Randy Thomasson.

"By bowing down to homosexual activists and the rebel city of San Francisco, the California Supreme Court has exchanged the rule of law for the rule of unbridled power to destroy all that is good and sacred," Thomasson said in a statement.

"The terrible example of homosexual 'weddings' should be short-lived. This extremely bad ruling will certainly spur Californians to vote in November to overrule the judges and protect marriage licenses for a man and a woman in the California Constitution," they said.

Three of the four Supreme Court justices are Republican appointees. Only Associate Justice Carlos Moreno was put on the bench by a Democrat, Gov. Gray Davis.

The Campaign for Children and Families called on Schwarzenegger to "resist any temptation to sign any bill opposing the people's vote on marriage."

In 2000, California voters backed Proposition 22 by a wide margin, banning the state from recognizing same-sex marriages from other states. Schwarzenegger used the initiative as justification to veto two bills that would have legalized gay marriage, saying voters should be the ones to decide.

Brown's office argued before the high court that marriage wasn't a required right under the state constitution, since gay and lesbian couples enjoy all the same rights as heterosexual couples.

Brown was governor when California first banned gay marriage, and he signed it into law. But he hasn't spoken publicly on the issue recently.

When the Bay Area Reporter, a gay and lesbian publication, asked about Brown's current stance on the issue during his run for attorney general two years ago, strategist Ace Smith answered: "Don't even go there."