SAN FRANCISCO, June 5 (Reuters) - The 9th U.S. Circuit Court of Appeals cleared the way on Tuesday for the U.S. Supreme Court to consider California's gay marriage ban, declining an appeal to revisit the case.

Supporters of the 2008 ban, Proposition 8, have lost two rounds in federal court but have made clear they will appeal to the U.S. Supreme Court and hope for a favorable response from the conservative-leaning court.

The top U.S. court could agree to hear the matter in the session beginning in October, putting it on track to decide the case within a year. It could also decline to review Prop 8.

President Barack Obama last month turned gay marriage into a 2012 campaign issue, saying he believed same-sex couples should be able to marry. Republican Mitt Romney disagrees.

The vast majority of U.S. states limit marriage to opposite-sex couples, and popular votes have consistently approved bans on widening those rights.

But polls show growing acceptance of same-sex nuptials, which have been legalized in eight states and the District of Columbia, thanks to votes by legislators and court decisions.

The 1st Circuit Court of Appeals in Boston last week ruled that the federal Defense of Marriage Act unconstitutionally denied benefits to same-sex couples in a state where gay marriage was legal.

The U.S. Supreme Court would set national precedent if it decided to take the California case. Appeals courts have so far declined to rule broadly on whether marriage is a fundamental human right for same-sex couples as well as heterosexuals. (Editing by Sandra Maler)

Loading Slideshow...

  • Jan. 3, 2000

    California begins registering domestic partners, allowing same-sex couples: hospital visitation rights and health insurance coverage for the dependents of government employees covered by CalPERS, the state retirement system.

  • March 7, 2000

    Proposition 22, a ballot measure which declares that marriage should remain between opposite sex couples, is approved by 61 percent of California voters.

  • Sept. 19, 2003

    California Governor Gray Davis signs a bill that gives state-registered domestic partners additional rights that, although stop short of recognizing gay marriage, allow surviving partners the right to collect government benefits from his or her partner and obtain custody is a partnership is ultimately dissolved.

  • Feb. 12, 2004

    Dozens of same-sex couples are married when San Francisco Mayor Gavin Newsom instructs city officials to issue marriage licenses. The excitement is short-lived, however, and on March 11, the California Supreme Court orders the city to stop marrying gay couples after nearly 4,000 have received licenses.

  • Aug. 12, 2004

    California's Supreme Court rules that Newsom overstepped his authority by allowing San Francisco to issue marriage licenses to same-sex couples, and the court also declares the nearly 4,000 couples "void from their inception and a legal nullity."

  • Dec. 21, 2004

    A San Francisco judge hears arguments on same-sex marriages, which argue that the current law defining marriage as being "between a man and a woman" violates the state Constitution by denying gay couples the "fundamental right" to marry a person of their choice.

  • Sept. 29, 2005

    Gov. Arnold Schwarzenegger vetoes a same-sex marriage bill after it passed the Senate and Assembly, arguing that it would wrongly reverse Proposition 22, which declares that marriage is only between a man and a woman.

  • Sept. 19, 2007

    San Diego Mayor Jerry Sanders reverses his public opposition to same-sex marriage, saying he cannot tell his daughter Lisa, who is a lesbian, that her relationship with a partner is not as important as that of a straight couple.

  • Oct. 12, 2007

    Schwarzenegger vetoes a bill approved by state lawmakers that would legalize gay marriage, saying the courts need to rule on the legality of Proposition 22, the gay marriage ban passed by voters.

  • May 15, 2008

    The California Supreme Court rules that the state Constitution protects a fundamental "right to marry" that should also extend to same-sex couples, and that existing bans are unconstitutional.

  • June 2, 2008

    The California Marriage Protection Act is submitted with over one million signatures. It appears as Proposition 8 on the November ballot.

  • Nov. 8, 2008

    Despite an onslaught of opposition from LGBT activists and allies, Proposition 8 passes with 52 percent of the vote.

  • Aug. 4, 2010

    U.S. District Court Judge Vaughn Walker declares,"Proposition 8 fails to advance any rational basis in singling out gay men and lesbians for denial of a marriage license. Indeed, the evidence shows Proposition 8 does nothing more than enshrine in the California Constitution the notion that opposite sex couples are superior to same sex couples. Because California has no interest in discriminating against gay men and lesbians, and because Proposition 8 prevents California from fulfilling its constitutional obligation to provide marriages on an equal basis, the Court concludes that Proposition 8 is unconstitutional."