The California Supreme Court ruled yesterday that San Francisco Mayor Gavin Newsom was wrong, legally, when he directed city employees to issue marriage licenses to thousands of same-sex couples. But some gay rights activists still believe he was right, politically.

"We saw for weeks on end in California -- and then New Mexico and New York and Oregon -- these parades of real people getting married," said Jon W. Davidson, senior counsel at the gay rights group Lambda Legal. "Even though it's been struck down, it served its broader political purpose: It made concrete and human what was a fairly abstract political discussion before."

Other supporters of the same cause disagreed. Rep. Barney Frank (D-Mass.), who opposed Newsom's approach from the beginning, called it a "strategic mistake" for the mayor to take the law into his own hands. "As a result nobody is married, you get negative headlines and you set people up. There were a lot of people who genuinely thought they were married. I thought it was wrong to lead them on that way," Frank said.

Despite the disagreement over tactics, Davidson and Frank share the widely held conviction within the gay rights community that legalization of same-sex marriage is inevitable. But their confidence is tempered by concern that after the rapid developments of the past year, a period of reversals and retrenchment is at hand.

Opponents of same-sex marriage also sense that they are on a roll. In addition to the California court decision, voters in Missouri last week passed a state constitutional amendment defining marriage as the union of one man and one woman. Similar referendums will appear on ballots this fall in as many as a dozen states.

"The momentum is shifting. Today's decision shows that gay marriage is not inevitable," said Glen Lavy, senior counsel at the Alliance Defense Fund, a Christian legal alliance.

He cited the results of all five referendums against same-sex marriage since 1998. They were approved by 69 percent of the voters in Hawaii, 68 percent in Alaska, 70 percent in Nebraska, 67 percent in Nevada and 71 percent in Missouri.

"That's the trend. Every time this has come before the voters, they have overwhelmingly, by a 2-to-1 margin or more, affirmed the traditional definition of marriage," Lavy said.

Both sides agreed that yesterday's decision did not settle the issue, even in California. The state Supreme Court emphasized that it was ruling only on whether an elected official such as Newsom can choose, on his own, to defy a state law that he believes is unconstitutional. It did not decide the underlying question of whether the state constitution requires homosexual and heterosexual couples to be treated equally.

That question is working its way through the California courts in another case, Woo v. Lockyer. The plaintiffs, 10 gay and lesbian couples and two gay rights organizations, make many of the same arguments that were accepted by the Massachusetts Supreme Judicial Court when it ruled last year that same-sex couples have a right to marry in that state.

Moreover, similar lawsuits are pending in at least seven other states: Washington, Oregon, New Jersey, New York, Maryland, Florida and Indiana. And gay rights supporters are winning not just in some courts but also in some legislative arenas. Fifteen state legislatures and the U.S. Senate have rejected proposed constitutional amendments on marriage, and the "Marriage License Non-Discrimination Act," a bill to allow same-sex marriage, picked up steam this year in California's State Assembly.

All this activity allows Evan Wolfson, head of the national group Freedom to Marry, to argue that the California court decision "was a pretty narrow ruling on what in some ways is a technical side point and doesn't in any way stop the momentum of ending marriage discrimination in the United States."

But Wolfson also predicted that more setbacks lie ahead for his side.

"We are headed for a period of patchwork," he said. "Some states move forward, and others retrench or regress, which is what always happens in civil rights movements."

For her part, Pam Cooke, 43, a Los Angeles lawyer whose marriage to longtime partner Nancy Felixson was invalidated yesterday, said she still believes Newsom's action was "the right way to expose the nation to the discrimination we've been facing."

"I will continue to call Nancy my spouse, because in my heart I know we are still married," she said. "We definitely do not regret going through the full process and opening people's eyes up to the fact that real people are involved."

Rep. Barney Frank (D-Mass.) called the licenses a "strategic mistake."