Ending a six-month legal battle and instantly igniting the next political fight, the California Supreme Court on Tueday upheld Proposition 8's ban on same-sex marriage, but left intact the unions of gay and lesbian couples who wed last year.

In a definitive 6-1 decision that cheered opponents of gay marriage, the justices said they would be overstepping their authority if they were to overturn the constitutional ban voters enacted Nov. 4. In the same ruling, the court established a two-tiered system of marriage for same-sex couples that seemed bound to satisfy no one.

Gay marriage advocates vowed Tuesday to take the fight to "win marriage back" to California voters in 2010. With same-sex marriage now legal in Iowa, Maine, Vermont, Massachusetts and Connecticut, supporters say they have momentum after a "sea change" of public opinion in recent months.

"It is impossible to square the elation we felt a year ago" — when the same seven justices struck down state prohibitions on same-sex marriage — "with the grief we feel today," said Kate Kendall, executive director of the National Center for Lesbian Rights. "It is clear this is not the end."

Supporters of Proposition 8, meanwhile, were thrilled with Tuesday's decisive 6-1 ruling, saying the judiciary had not just backed the will of the people in the 52-48 percent margin of the November vote, but had reaffirmed the power of initiative government in California.

"What the court's decision clearly states is that if the definition of marriage is going to change," said Andrew Pugno, general counsel of ProtectMarriage.com, "it's going to have to change at the ballot box."

Sad celebration

Like thousands of same-sex married people across the state, Lisa Miller took a nervous break from work at Stanford's Hoover Institution at 10 Tuesday morning, in anticipation of the court decision.

She and her wife, Paula Jabloner, were married in San Jose a few days before voters passed the gay marriage ban. But when the radio intoned the news of two seemingly conflicting things — the court had affirmed her union, but also the vote banning gay marriage — Miller and many other same-sex couples felt guilt and disappointment as strongly as relief. Instead of celebrating, Miller and Jabloner planned to go to a protest Tuesday night — one example of how the latest judicial ruling on same-sex marriage will reverberate through California politics into 2010 and perhaps beyond.

"It mostly hurts," said the Hoover Institution archivist, sitting alone in her basement office moments after the ruling, the murmur of scholars outside mingling with the radio.

'Hollowest victory'

Despite the ruling, even Pugno of ProtectMarriage.com predicted the two-tiered system for same-sex couples would inevitably lead to more litigation, even as the focus turns once again to the ballot box.

For many of the estimated 18,000 same-sex couples who legally married in California between June 16 and Election Day the emotions that followed the court ruling were a sharp and unwelcome mixture of relief, guilt and sadness.

"It's got to be the hollowest victory around," Miller said. "I'm in a top tier, and everybody else is in another."

She picked up the phone and dialed Jabloner, an archivist at the Computer History Museum in Mountain View.

"So we're still married," Miller said, her voice quiet and flat, when Jabloner picked up the phone. "People congratulating you? "... That's good."

The situation made David Speakman, part of one of the first two same-sex couples to marry in Santa Clara County in June, feel as if he were "on an island" with the 36,000 other gay men and lesbians who wed legally last year.

"It's an odd feeling because Rich and I are still married, but we are separated from other married people who are different-sex couples, because we'll be under the obligation to prove we're married," Speakman said. "We're also separated from the other gay people who can't get married, because we have something they can't get."

With that "moral dilemma," he is thinking about boycotting all weddings — except in states that recognize same-sex marriage.

Future battles

In San Francisco, where gay marriage has swung like a pendulum between legal and illegal over the past five years, at least 2,000 "marriage equality" supporters gathered in front of the Supreme Court on Tuesday morning to await the ruling.

After the court's decision was released, hundreds of people somberly walked across the plaza to San Francisco City Hall, where the first gay marriages were performed in February 2004. Later, a throng of protesters blocked the nearby intersection of Van Ness Avenue and Grove Street.

But like many San Francisco protests, this was a juxtaposition of anger with near-celebration, as each arrest was greeted by applause, a blast of music from an impromptu brass band and a gay couple making out in front of the riot officers. About 175 protesters were arrested in a peaceful, methodical operation by San Francisco police.

Overall, said Anthony Turney, a 71-year-old Episcopalian archdeacon at Grace Cathedral who was preparing to be arrested for his first time, "this is a sad day."

"If I am going to call myself a Christian," he said, "that is incompatible with denying rights to any minority."

Associate Pastor Chauncey Killens of Salinas, meanwhile, was literally chased away from the protest when he expressed his support for Proposition 8.

"I'm here to support the 7 million who voted for Proposition 8," Killens said. He said he was disappointed he could not get his bull-horned message heard over the boos.

"And they call us hateful and bigoted," he said.

In downtown San Jose Tuesday evening, a crowd of about 300 protested and marched with a mix of anger, disappointment and a resolve to repeal Proposition 8.

"I'm mad as hell, everyone,'' David Parker said through a microphone at Plaza de Cesar Chavez Park. Unmarried and 33, the president of the Silicon Valley Lesbian, Gay, Bisexual, Transgender Democratic Club, brought along a petition for a ballot initiative that would repeal Proposition 8. "We are not done,'' he said, "we are here to stay and we're not rolling over.''

Damaris Pyle and Connie Slemmer carried a sign saying they were wed Sept. 22, 2009, just weeks before voters approved Proposition 8.

It's bittersweet and confusing, Pyle said.

The court's Solomonic decision, which let some 18,000 gay marriages stand while outlawing new unions, did not sit well with her wife, either.

"We're in limbo,'' Slemmer said. "We feel like second-class citizens where our marriage is not seen as equal to others.''

Next moves

The shape of the next political campaign over same-sex marriage was already taking shape Tuesday with the attitudes of minority voters certain to be one battleground.

Mindful of their poor performance with minority voters on Proposition 8, gay-marriage advocates vowed to do a better job of winning over Latinos, African-Americans and the faithful this time around. Spanish-speaking organizers will be hired to do outreach in the Central Valley, and faith leaders will play a key role. There's already a slogan: "Win Marriage Back: Make it Real!"

Meanwhile, Proposition 8 supporters were also readying for the next battle. They promised a public outreach campaign to young people, churches, and "ethnic communities" on the benefits of the traditional definition of marriage as one man and one woman.

"This is not over," said the Rev. Nestor Morales, the pastor of the Generations Foursquare Church in San Jose. "We're going to be very clear, very coherent and united."

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Mercury News Staff Writer Joe Rodriguez contributed to this report.