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The Obama administration is considering urging the Supreme Court to overturn California's ban on gay marriage -- a move that could have a far-reaching impact on same-sex couples across the country.

The administration has one week to file a friend-of-the-court brief with the justices on the California ban, known as Proposition 8. While an administration brief alone is unlikely to sway the high court, the government's opinion does carry weight with the justices.

Proposition 8 opponents believe the president signaled his intention to file a brief when he declared in last month's inaugural address that gays and lesbians must be "treated like anyone else under the law." An administration official said Obama was not foreshadowing any legal action, though the administration was considering filing a brief.

The Proposition 8 ballot initiative was approved by California voters in 2008 and overturned a state Supreme Court decision allowing gay marriage. Twenty-nine other states have constitutional amendments banning gay marriage, while nine states and Washington, D.C., recognize same-sex marriage.

An administration brief alone is unlikely to sway the Justices but the federal government's opinion does carry weight with the court.

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A final decision on whether to file a brief has not been made, a senior administration official said. Solicitor General Donald Verrilli is consulting with the White House on the matter, said the official, speaking only on condition of anonymity because the official was not authorized to address the private deliberations publicly.

While the Justice Department would formally make the filing, the president himself is almost certain to make the ultimate decision on whether to file.

"I have to make sure that I'm not interjecting myself too much into this process, particularly when we're not a party to the case," Obama said Wednesday in interview with San Francisco's KGO-TV.

He said his personal view is that gay couples should have the same rights as straight couples and said his administration would do whatever it could to promote that principle.

Obama has a complicated history on gay marriage. As a presidential candidate in 2008, he opposed the California ban but didn't endorse gay marriage. As he ran for re-election last year, he announced his personal support for same-sex marriage but said marriage was an issue that should be decided by the states, not the federal government.

To some, Obama's broad call for gay rights during his Jan. 21 inaugural address was a signal that he now sees a federal role in defining marriage.

"Our journey is not complete until our gay brothers and sisters are treated like anyone else under the law," Obama said during his remarks on the steps of the U.S. Capitol. "For if we are truly created equal, than surely the love we commit to one another must be equal as well."

But administration officials said Obama -- a former constitutional law professor -- was not foreshadowing any legal action in his remarks and was simply restating his personal belief in the right of gays and lesbians to marry.

Seeking to capitalize on growing public support for gay marriage, advocates are calling on the administration to file a broad brief not only asking the court to declare California's ban unconstitutional but also urging the Justices to make all state bans illegal.

"If they do make that argument and the court accepts it, the ramifications could be very sweeping," said Richard Socarides, an attorney and advocate.

The administration could also file a narrower brief that would ask the court to issue a decision applying only to California. Or it could decide not to weigh in on the case at all.

The Supreme Court, which will take up the case on March 26, has several options for its eventual ruling. Among them:

-- The justices could uphold the state ban on gay marriage and say citizens of a state have the right to make that call.

-- The court could endorse an appeals court ruling that would make same-sex marriage legal in California but apply only to that state.

-- The court could issue a broader ruling that would apply to California and seven other states: Delaware, Hawaii, Illinois, Nevada, New Jersey, Oregon and Rhode Island. In those states, gay couples can join in civil unions that have all the benefits of marriage but cannot be married.

-- The broadest ruling would be one that says the Constitution forbids states from banning same-sex unions.

For weeks, supporters and opponents of Proposition 8 have been lobbying the administration to side with them.

Last month, Theodore Olson and David Boies, lawyers arguing for gay marriage, met with Verrilli and other government lawyers to urge the administration to file a brief in the case. A few days later, Charles Cooper, the lawyer defending Proposition 8, met with the solicitor general to ask the government to stay out of the case. Those kinds of meetings are typical in a high court case when the government is not a party and is not asked by the court to make its views known.

Boies and Chad Griffin, president of the advocacy group Human Rights Campaign, also had a meeting at the White House on the case.

Ahead of next week's deadline, nearly two dozen states have filed briefs with the Supreme Court asking the Justices to uphold the California measure.

"There's a critical mass of states that have spoken out and believe states should continue to have the right to define marriage as between one man and one woman," said Jim Campbell, legal counsel for the Alliance Defending Freedom, which represents supporters of Proposition 8.

Public opinion has shifted in support of gay marriage in recent years. In May 2008, Gallup found that 56 percent of Americans felt same-sex marriages should not be recognized by the law as valid. By November 2012, some 53 percent felt they should be legally recognized.

Obama has overwhelming political support among those who support same-sex marriage. Exit polls from the November election showed that 49 percent of voters believed their states should legally recognize gay marriage. More than 70 percent of those voters backed Obama over Republican nominee Mitt Romney.

One day after the court hears the California case, the justices will hear arguments on another gay marriage case, this one involving provisions of the federal Defense of Marriage Act, known as DOMA. The act defines marriage as between a man and a woman for the purpose of deciding who can receive a range of federal benefits.

The Obama administration abandoned its defense of the law in 2011 but continues to enforce it. Because DOMA is a federal law and the government is a party to the case, the administration does not have to state its opposition through a friend of the court brief.