The Obama administration is quietly considering urging the Supreme Court to overturn California’s ban on gay marriage, a step that would mark a political victory for advocates of same-sex unions and a deepening commitment by President Barack Obama to rights for gay couples. Obama raised expectations among opponents of the Proposition 8 ban when he declared in last month’s inaugural address that gays and lesbians must be “treated like anyone else under the law.” The administration has until Feb. 28 to intervene in the case by filing a “friend of the court” 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. 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. 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.