The California Supreme Court will reveal its decision on the fate of gay marriage Tuesday morning when it rules on the constitutionality of Proposition 8, the court announced Friday.

But even before the court acts, gay rights activists -- braced for defeat -- are preparing to use the occasion to jump-start the next political campaign for gay marriage, which could come in 2010. They are planning news conferences, vigils and marches from South Los Angeles to the Oregon border. That’s because legal experts predict that the justices will uphold the proposition.

“We hope they rule the right way, but we are prepared to win marriage back at the ballot box,” said Marc Solomon, the marriage director of Equality California, one of the state’s leading gay rights groups.

Opponents of gay marriage said they were anticipating a court ruling in their favor.


“The wait is finally over . . . and we’re confident that the right of the people to protect traditional marriage in the state Constitution will ultimately prevail,” said Andrew Pugno, general counsel for ProtectMarriage.com, in a statement.

The ruling, which will be posted on the court’s website at 10 a.m., will also determine whether an estimated 18,000 same-sex marriages performed between June and November will continue to be recognized by the state.

Gay rights lawyers went to court to throw out Proposition 8, the November ballot measure that resurrected a ban on same-sex marriage, the day after voters approved it 52% to 48%. The attorneys argued that the measure was an illegal constitutional revision rather than a more limited amendment.

State Atty. Gen. Jerry Brown urged the court to reject the measure on different grounds. He contended that the proposition was unconstitutional because it took away an inalienable right without compelling justification.


Chief Justice Ronald M. George and Justice Joyce L. Kennard will cast key votes in the case. They were part of the four-judge majority that gave gays the right to marry last May, but both indicated at oral argument that they were not convinced the measure was unconstitutional.

During oral argument in March, every justice expressed support for upholding existing same-sex marriages. Justice Carlos M. Moreno, who has been talked about as a possible U.S. Supreme Court nominee, indicated that he believed Proposition 8 was an illegal revision, suggesting that he would dissent on that issue.

Moreno might be joined by Justice Kathryn Mickle Werdegar, a former civil rights lawyer who stressed that the court was dealing with a novel legal question. Werdegar, however, did not join Moreno in voting to put the measure on hold pending the court’s ruling.

During the six months that the court has been reviewing the case, the national picture on gay marriage has shifted substantially.


Before last fall, California and Massachusetts were the only states to permit same-sex marriage. Iowa, Connecticut, Vermont and Maine have since legalized it, and lawmakers in New York, New Jersey and New Hampshire are considering bills of their own.

Proponents of gay marriage in California hope that the raft of other states permitting gay marriage will influence voters here.

But starting Tuesday, they will also be launching their own campaign to change minds.

“Whatever the court does . . . we have roughly half the state that doesn’t yet believe that gay people are equal,” said Jenny Pizer, Marriage Project director for Lambda Legal.


--

jessica.garrison@latimes.com

maura.dolan@latimes.com