LOS ANGELES — Within moments of the announcement Friday that the Supreme Court would hear two cases relating to same-sex marriage, gay activists rejoiced, heralding the decision as a major advancement for their movement.
‘’Today’s news is nothing short of a milestone moment for equality,’’ said Chad Griffin, a champion of the legal challenge to Proposition 8, the California initiative passed in November 2008 that banned same-sex marriage and is now heading to the Supreme Court.
Yet amid the celebration, there were signs of concern over how the Supreme Court might rule. The fact that the Supreme Court is hearing the cases hardly means it is about to ratify same-sex marriage. As supporters and opponents said in interviews, the court might well use these cases to find that there is no constitutional protection for same-sex marriage.
‘‘There is no question that it is a risk,’’ said Lt. Gov. Gavin Newsom of California. ‘‘If they nationalize it and reject it, that’s going to take decades to come back to the court.’’
As the mayor of San Francisco, Newsom began issuing marriage licenses to same-sex couples just over a month after his election in 2004 until he was stopped by the courts.
Newsom said he trusted the counsel of the high-profile lawyers for the plaintiffs, David Boies and Theodore B. Olson, that this time and this court were right for the case.
‘‘I’m going to defer to their expertise rather than my instincts,’’ Newsom said. ‘‘I think it’s worth the risk.’’
Jubilation was tempered with apprehension as the implications of the decision were discussed across the country.
‘’That the Supreme Court is taking this up is truly exhilarating, but I’m very nervous and unnerved by the possibilities of what could come out of this,’’ said Don Romesburg, 42, an associate professor of women and gender studies at Sonoma State University.
‘’It is frightening to have our basic rights as citizens in the hands of just nine people, when four or five of them are deeply ambivalent, at best, about our very existence,’’ said Romesburg, who legally married his male partner during the window before Proposition 8 was passed.
Angela Gabriel, 43, a lesbian in Atlanta, said she was cautiously optimistic that the court would rule in favor of same-sex marriage, but was concerned about the ramifications of that outcome in socially conservative regions.
‘‘Georgia is just not as progressive or forward-thinking or accepting of everyone,’’ she said. ‘‘There would be a lot of pushback.’’
When Griffin, who now heads the Human Rights Campaign, and other California gay rights leaders sought to overturn Proposition 8, they encountered a wave of criticism from some established gay rights groups that were fearful that the Supreme Court would rule against them.
‘’An unsuccessful challenge may delay marriage even longer, not only in California but in other states, and seriously damage the rights’’ of gay men and lesbians on a range of issues, the groups said in May 2009. The organizations, which included the Human Rights Campaign and Lambda Legal, cautioned against ‘‘premature’’ legal action.
But Griffin said he was always confident of victory, now more than ever.
‘‘Look, we wouldn’t have filed this case were we not optimistic that once this case finally reached the Supreme Court that it would come down on the side of liberty and equality,’’ he said. ‘‘Throughout the history and struggle for civil rights in this country, there have always been those who said slow down. But at the end of the day, millions of gay and lesbian Americans are counting on us to stand up for them and for our most basic constitutional principles.’’
Evan Wolfson, the president of Freedom to Marry, said the legal victories over the last four years had created a decidedly different environment for the Supreme Court than when gay leaders battled over the wisdom of bringing this challenge.
‘’Since then, we’ve made enormous progress and built irrefutable momentum, winning the freedom to marry in state after state and winning over a solid majority of support in this country,’’ he said.
Kate Kendell, the executive director of the National Center for Lesbian Rights, which initially opposed court action, said she now expected the court to rule in favor of same-sex marriage.
‘‘There is no doubt that the wind is at our backs,’’ she said. ‘‘We’ve hit a tipping point on this issue. I think we are better positioned than ever.’’
In Atlanta, Josh Bergeleen, 20, a junior at Emory University, said he was not concerned about the outcome. ‘‘Yes, it’s a very conservative court,’’ he said. ‘‘But momentum is moving in favor of gay marriage.’’
Romesburg of Sonoma State University said he was more concerned about the future.
‘‘My gut says that the next six months are going to be really hard,’’ he said. ‘‘When I heard the Supreme Court would consider Prop 8, my initial feeling was ‘Here we go again.’’’
In Cambridge, Mass., Kevin McDonald, 26, a graduate student at Harvard, said he was ‘‘pretty excited’’ to hear about the decision, but drew comparisons to the unwelcome ramifications for the abortion rights movement.
‘’I’m not sure we’re there yet — we’re making really good progress — but I don’t want to see that progress impeded somehow, with a ruling that makes people feel like they don’t have control over something so fundamental like marriage,’’ he said.
Reporting was contributed by Ian Lovett from Los Angeles, Malia Wollan from San Francisco, Robbie Brown from Atlanta and Jess Bidgood from Boston.