WASHINGTON - President Obama, in saying this week that his view of same-sex marriage is evolving, stirred expectations that he may announce a new position in the coming months, fundamentally altering the national debate.

A declaration from a sitting president that he supports same-sex marriage would be "a game-changer," one proponent said, and would provide political cover to other politicians, especially to local and state officials as they decide which way to vote on bills permitting gay couples to wed.

During a news conference Wednesday and in recent interviews, Obama signaled that his position favoring civil unions is not fixed and that he may one day conclude that a committed gay couple should have the same right to marry as anyone else.

Obama has not reached that point yet, though, and has given no timetable for when, if ever, he may announce a change of mind.

But White House officials indicated there was more than personal reflection behind his comments. An immediate goal, the White House said Thursday, is the repeal of a Bill Clinton-era law, the Defense of Marriage Act, that defines marriage as a union between a man and a woman. The law holds that couples who don't meet this description are not eligible for federal benefits.

Obama, using the forum of his national news conference, gave a window into his thinking about a volatile social issue on which there is no clear public consensus. Earlier that day, he had signed a bill repealing the ban on gays serving openly in the military. ABC's Jake Tapper asked Obama, if gays can fight and die for their country, why can't they marry people they love?

"I struggle with this," the president responded. "I have friends, I have people who work for me, who are in powerful, strong, long-lasting gay or lesbian unions. And they are extraordinary people, and this is something that means a lot to them and they care deeply about."

Obama's views seem to be tracking those of the broader American public. Polls show that support for same-sex marriage is growing. A Gallup study showed that whereas in 1996 only 27 percent of the population thought same-sex marriage should be legalized, the figure had risen to 44 percent by May.

In August, 52 percent of those queried in a CNN Opinion Research poll said gay Americans "should have a constitutional right to get married."

Vice President Biden, in an interview Friday on ABC's Good Morning America, said, "I think the country's evolving" in a way that would eventually bring about a national consensus for same-sex marriage.

Many social conservatives, such as Eagle Forum president Phyllis Schlafly, refuse to believe that a majority of Americans would support that.

Obama's shifting position, she said, "is the story of politics: An aggressive, well-funded pressure group can achieve goals contrary to what the majority of people want. I think same-sex marriage would be a terrible mistake. I don't think there are any good arguments for it."

Gay people, Schlafly said, are already free to live together. "Nobody's stopping them from shacking up," she said. "The problem is they are trying to make us respect them, and that's an interference with what we believe."

An incoming class of conservative lawmakers will have other priorities next year. A House Republican aide said Thursday that the new GOP House majority was focused on repealing Obama's health-care overhaul, cutting spending, and reining in government.

"As far as I know, there are no plans" for addressing the gay-marriage issue in the opening months of Congress, said the aide, who was not authorized to speak publicly and requested anonymity.

Because marriage is controlled by the states, there is little Obama can do on his own to expand same-sex marriage. But a strong public position by the president in favor of it could help shape public opinion.

At present, five states and the District of Columbia license same-sex marriages.

Should Obama come out in favor of same-sex marriage, "it would be a game-changer," said Denis Dison, vice president of the Gay and Lesbian Victory Fund, which works to elect openly gay candidates to public office.

Even Obama's acknowledgment that he's wrestling with the issue, Dison added, "is a pretty big deal."

Obama has appointed more than 150 openly gay people to posts in his administration - more than all other presidents combined, according to the Gay and Lesbian Victory Fund.

In his book The Audacity of Hope, published in 2006, Obama signaled that his opposition to same-sex marriage, rooted in his religious views, wasn't unshakable.