California's Senate has voted to allow gay marriage (search), making it the first legislative body in the nation to back the idea and setting off a frantic scramble for votes in the Assembly.

The 21-15 vote Thursday handed gay rights advocates in the country's most populous state a historic victory. Vermont and Massachusetts issued marriage licenses to gays and lesbians only after court rulings.

"We are so very close," said Assemblyman Mark Leno (search), a Democrat who wrote the bill. "It would be very disappointing for this body not to be able to stand up for civil rights."

Leno said he planned to bring up the bill Tuesday and predicted that the Senate vote would help sway his undecided colleagues. In June, the Assembly rejected his bill by four votes.

Gov. Arnold Schwarzenegger's (search) office had no comment Thursday on how the governor would respond if the bill reached his desk, spokeswoman Margita Thompson said.

Several senators equated the struggle for gay marriage to the civil rights movements. They said arguments against the bill were similar to arguments in supporting slavery and opposing interracial marriage.

"This is probably the most profound civil rights movement of our generation, without a doubt," said Sen. Jackie Speier, a Democrat who supported the bill.

Sen. Sheila Kuehl, one of six gay members of the Legislature, told the chamber that gay couples have the same hopes for their relationships as heterosexual couples.

"Gay and lesbian people fall in love. We settle down. We commit our lives to one another. We raise our children. We protect them. We try to be good citizens," said Kuehl, a Democrat. "This is a bill whose time has come."

But Republican Sen. Tom McClintock, an opponent of the bill, said gay couples are entitled to certain rights but not the right to marry.

"Can't you see that marriage is a fundamentally different institution?" he asked.

"This is not the right thing to do," said Republican Sen. Dennis Hollingsworth. "We should protect traditional marriage and uphold all of those values and institutions that have made our society and keep our society together today."

Senate approval gave Leno another chance to get the bill passed. After the Assembly rebuffed his first attempt, he amended the measure's provisions into another bill that had already passed the Assembly and was awaiting action in the Senate. That was the bill the Senate approved Thursday and sent back to the Assembly.

California already confers many of the rights and duties of marriage on gay couples, who can register as domestic partners. Voters in 2000 also approved Proposition 22, which added a section to the state Family Code stating that "only marriage between a man and a woman is valid or recognized in California."

The proposition was put on the ballot when it appeared that Hawaii might legalize gay marriages and was intended to prevent California from recognizing gay marriages performed elsewhere.

The state Senate vote came as a state appellate court considered appeals of a San Francisco judge's ruling that overturned California laws banning recognition of gay marriages.

At the same time, opponents of same-sex marriage are trying to qualify initiatives for the 2006 ballot that would place a ban on gay marriages in the state Constitution.

Defenders of same-sex marriage took a longer view.

"Equality is equality, period," said one of the bill's supporters, Democrat Sen. Liz Figueroa. "When I leave this Legislature, I want to be able to tell my grandchildren I stood up for dignity and rights for all."