SAN FRANCISCO -- It was a jolt of energy for a crowd of about 150 people wilting in the midday heat outside the California Supreme Court building in San Francisco.

Read: Calif. Supreme Court Ruling (.pdf)

Word came Thursday that the Republican-controlled state high court had voted 4-3 to overturn a state law banning same-sex marriage. It touched off a raucous celebration. People jumped for joy, cheered and cried. Horns on passing cars honked -- and congratulations were shouted to same-sex couples.

The long wait for Shelly Bailes and Ellen Pontac illustrates the jubilation.

They've been together more than 34 years, but had to hide their relationship while their four children were in school. Otherwise, Pontac said, their kids would have been taken away, adding "that's why this is such a big deal."

Marriages Could Start Next Month

The justices released the 4-3 decision, saying that domestic partnerships are not a good enough substitute for marriage.

The decision paves the way for California to become the second state where gay and lesbian residents can marry.

Same-sex couples could tie the knot in as little as a month. But the window could close soon after -- religious and social conservatives are pressing to put a constitutional amendment on the ballot in November that would undo the Supreme Court ruling and ban gay marriage.

The cases were brought by the city of San Francisco, two dozen gay and lesbian couples, Equality California and another gay rights group in March 2004. They were filed after the court halted San Francisco's month-long same-sex wedding march that took place at Mayor Gavin Newsom's direction.

Several of those plaintiffs stood on the courthouse steps Thursday, cheering and weeping with joy as the decision came down.

"We are thrilled to celebrate today," said Beth Teper, according to Sacramento television station KCRA. Teper is executive director of Children Of Lesbians And Gays Everywhere, an organization representing families with one or more gay, lesbian or transgender parents.

Mayor Gavin Newsom's spokesman, Nathan Ballard, sent out a two-word text message to the mayor's staff upon hearing the decision.

"We won!" it read.

'Will You Marry Me?'

Soon after the decision was announced, one of the plaintiffs in the case phoned her longtime partner to ask, "Will you marry me?

She said the ruling sends a message of human dignity and freedom. In the center of San Francisco's gay community, people wept with joy as they watched the news on television.

Meanwhile, religious and social conservative groups tried to put a measure on the November ballot that would enshrine laws banning gay marriage in the state constitution.

The conservative Alliance Defense Fund said it plans to ask the state justices for a stay of Thursday's decision until after the fall election.

The court also noted that it had ruled earlier that Newsom acted illegally by approving those marriages before the issue had been settled. However, that did not settle the issue of the ban on same-sex marriage.

Six of the seven justices on the court were appointed by Republican governors.

Schwarzenegger Reacts

The state legislature has twice approved legislation to legalize gay marriage. But both measures were vetoed by Gov. Arnold Schwarzenegger, but he vowed to uphold the ruling.

The Republican governor issued a brief statement shortly after the court announced its decision.

He also reiterated his previously stated opposition to an anti-gay marriage initiative proposed for the November ballot. That initiative would write a ban on same-sex unions into California's constitution.

Last month, Schwarzenegger told a gathering of gay Republicans that he would fight the initiative.

Schwarzenegger did not address the court's ruling in his address to a technology conference in Sacramento Thursday morning.