WASHINGTON — The Obama administration told the Supreme Court on Thursday that California’s ban on same-sex marriage violates the Constitution’s guarantee of equal protection, a position that could also cast doubt on prohibitions in other states.
The administration did not endorse a constitutional right to marry that would apply nationwide.
But its friend-of-the-court brief, a bold declaration of the administration’s interest in gay rights, said the court should review laws banning same-sex marriage under ‘‘heightened scrutiny.’’
The administration’s entry for the first time into the legal battle over Proposition 8 — a voter initiative that amended the California State Constitution in 2008 to limit marriage to a man and a woman — also carried great symbolic value for those advancing the cause of marriage equality.
The Obama administration did not have to file a brief in the California case but said the question of how the court reviews laws that ‘‘target gay and lesbian people for discriminatory treatment’’ is of great interest to the government.
In California’s case, Solicitor General Donald Verrilli Jr. wrote, the state offers same-sex couples domestic partnerships but withholds marriage.
‘‘California’s extension of all of the substantive rights and responsibilities of marriage to gay and lesbian domestic partners particularly undermines the justifications for Proposition 8,’’ the brief says. ‘‘It indicates that Proposition 8’s withholding of the designation of marriage is not based on an interest in promoting responsible procreation and child-rearing — petitioners’ central claimed justification for the initiative — but instead on impermissible prejudice.’’
Those defending Proposition 8 say that the state’s acceptance of domestic partnerships proves voters were animated by a desire to protect traditional marriage, not to discriminate against homosexuals.
The government’s brief noted that seven other states have similar domestic partnership laws: Delaware, Hawaii, Illinois, Nevada, New Jersey, Oregon and Rhode Island. But it did not call for the court to overturn those laws.
In some ways, the brief marks a compromise between threatening the prohibitions on same-sex marriage that the vast majority of states have enacted and nudging along the number of states that allow such unions.
The administration has been under pressure from gay rights groups and others to enter the Proposition 8 case, especially after President Obama’s inaugural address, in which he said, ‘‘If we are truly created equal, than surely the love we commit to one another must be equal as well.’’
Adam Umhoefer, executive director of the American Foundation for Equal Rights, called the brief ‘‘a powerful statement that Proposition 8 cannot be squared with the principles of equality upon which this nation was founded.’’
‘‘It is an unprecedented call to action by our government that it is time to recognize gay and lesbian Americans as full and equal citizens under the law,’’ he said.
Thomas Peters, communications director of the National Organization for Marriage and a supporter of Proposition 8, said his group ‘‘expects the Supreme Court to exonerate the votes of over 7 million Californians to protect marriage.’’
The Obama administration’s entry into the legal battle carried great symbolic value.
‘‘The President is clearly fulfilling a campaign promise to wealthy gay marriage donors,’’ Peters said in a statement. ‘‘There is no right to redefine marriage in our Constitution.’’
The Supreme Court will consider two cases concerning same-sex marriage at the end of the month.
One addresses the Defense of Marriage Act, which restricts the federal government from recognizing same-sex marriages performed in those states where such unions are legal.
For two years, the administration has said that is unconstitutional, and a string of
lower court decisions have agreed.
The other is Proposition 8, which was passed by voters after the California Supreme Court recognized a right for same-sex unions under the state constitution. More than 18,000 couples were wed in the meantime.
A federal district court and the US Court of Appeals for the Ninth Circuit struck down the amendment.
While the Defense of Marriage Act case concerns couples who are already married, the Proposition 8 case offers the Supreme Court a chance to examine whether there is a constitutional right to marriage that cannot be denied by the states.
But, as the administration’s brief indicated, there are more limited ways the court could rule.
Currently, the District of Columbia, Maryland and eight other states allow same-sex marriages, while nearly all the rest forbid it.