The Obama administration Thursday filed a legal brief supporting same-sex marriage in California and urging the U.S. Supreme Court to overturn the state’s Proposition 8 when it weighs the matter in late March.

President Barack Obama has previously stated that questions about marriage rights should be left to states. However, the brief states that the California measure is unconstitutional and raises questions about the legality of similar statutes in seven other states.

“Proposition 8, by depriving same-sex couples of the right to marry, denies them the ‘dignity, respect and stature’ accorded similarly situated opposite sex couples under state law and does not substantially further any important governmental interest,” states the brief by Solicitor General Donald B. Verrilli Jr.

Obama affirmed support of gay and lesbian rights in his second inaugural address in January. His administration in 2011 stopped defending the 1996 Defense of Marriage Act, which recognizes only heterosexual marriages for federal and interstate purposes such as income taxes and health insurance.

Republican congressional leadership, using the Bipartisan Legal Advisory Group in the House, has defended the statute in courts since then. The Supreme Court will also weigh the constitutionality of the federal law in late March.

Same-sex marriage advocates Thursday applauded the administration’s intervention in the Proposition 8 case, Hollingsworth v. Perry.

“In its friend of the court brief filed today, the Justice Department provided the legal roadmap, calling on the Supreme Court to uphold the Constitution’s command of equal protection under the law,” Evan Wolfson, founder and president of Freedom to Marry, said in a statement. “It is time for the justices, like our president and the majority of Americans, to embrace the freedom to marry and get our country on the right side of history.”

California voters in 2008 narrowly approved Proposition 8, which amended the state’s constitution to limit marriage to opposite-sex couples.

Two same-sex couples sued in federal court in San Francisco, saying the measure violated the Due Process and Equal Protection clauses of the Constitution.

Though a divided panel of the 9th U.S. Circuit Court of Appeals in San Francisco ruled that Proposition 8 was an unconstitutional violation of the Equal Protection Clause of the 14th Amendment, it stayed its ruling while the parties appealed. Therefore, marriage license have not be granted to same-sex couples in California while the Supreme Court considers the case.