The California Supreme Court upheld on Tuesday a ban on gay marriage approved by the state's voters in November, but it allowed same-sex marriages performed before the initiative's passage to stand.
The 6-1 decision, written by Chief Justice Ron George, came as a victory for traditional-marriage proponents, who had fought what many analysts regarded as a losing battle last year to overturn the California Supreme Court's decision overturning an earlier state law defining marriage as the union of one man and one woman.
"We're grateful this court did not overturn the civil rights of all Californians to amend our own constitution," said Brian Brown, executive director of the national Organization for Marriage. "The 7 million Californians who worked hard to protect marriage as the union of husband and wife are breathing easier today."
The court rejected the argument made by proponents of gay marriage that Proposition 8 changed the meaning of the state constitution's equal protection clause so radically that it was revision of the document rather than an amendment to it. "Revisions" have to go through a different set of procedures than "amendments," which would have meant Proposition 8 was not validly passed.
Supporters of gay marriage disagreed with the decision but added that they were relieved to see the court recognize same-sex marriages already on the books. About 18,000 same-sex marriages were performed after the high court's May 2008 decision.
The Courage Campaign, a California-based gay-rights group, announced immediately that it would launch a petition-gathering campaign to put an initiative legalizing same-sex marriage on the 2010 ballot.
"While we are pleased that the court recognized the legal marriages of 18,000 same-sex couples in 2008, we are saddened by the Prop 8 decision," said Courage Campaign chair Rick Jacobs in an e-mail. "It's time to go on offense."
Supporters of traditional marriage had said they would launch a recall effort aimed at the California Supreme Court justices if Proposition 8 were overturned.
The California high court touched off a political battle royal last year when it overturned a state law banning gay marriage, ruling that the ban violated the "fundamental constitutional right to form a family relationship."
Conservative groups promptly collected more than 1.1 million signatures to place a traditional-marriage constitutional amendment on the November ballot. Dubbed Proposition 8, the measure passed by a margin of 52 percent to 48 percent.
Analysts later said that a surge in minority voters, inspired by the presence of Democratic presidential candidate Barack Obama on the ballot, helped push Proposition 8 over the top. Exit polls showed that most black and Hispanic voters who checked the box for Mr. Obama also backed Proposition 8.
The vote touched off an outcry among gay-rights groups and activists, who launched days of protests across the state.
Boycotts targeted businesses whose owners supported Proposition 8, and individuals who contributed to the Proposition 8 campaign reported being threatened and abused by angry gay-marriage supporters.
The Church of Jesus Christ of Latter-day Saints came under attack for its support of Proposition 8. A Mormon temple in Westwood, Calif., was evacuated after receiving in the mail a packet of white powder, which turned out to be nontoxic.
Another envelope of white powder was mailed to the church's headquarters in Salt Lake City. That substance also proved to be harmless, but a room was decontaminated and a building shut down for more than an hour.