As legal reporter Lyle Denniston of SCOTUSblog explains, "The brief recommended that the Court, for the first time, apply a tough constitutional standard to Proposition 8 -- the standard that goes by the technical name 'heightened scrutiny.' It means that such a law must serve an important government interest, and be effective in doing so." Denniston observed that states which currently ban same sex marriage "would have difficulty passing that test."
The brief completes a dramatic turnaround by the president.
In 2008, he campaigned on a platform of opposition to gay marriage. Early in his presidency, he directed his administration to defend the Defense of Marriage Act, which prohibits federal recognition of legal same sex unions. His Justice Department even invoked cases that involved people marrying first cousins and children, infuriating gay rights advocates.
"I believe marriage is between a man and a woman," Obama told MTV on Nov. 2, 2008. "I am not in favor of gay marriage."
The tide turned on Feb. 23, 2011, when the Obama administration announced that it would no longer defend DOMA, arguing that the law violated the Constitution's guarantee of equal protection. The following year, in the heat of a presidential campaign, he came out for legalizing same sex marriage. Last week's brief takes it a step further by pushing the highest court in the land to enshrine that view as a constitutional principle.
"The basic principle that America is founded on, the idea that we are all created equally, applies to everybody, regardless of sexual orientation as well as race or gender," Obama told reporters at a press conference Friday, saying he would rule against all gay marriage bans if he were on the Supreme Court. "Let's treat everybody fairly. Let's treat everybody equally."
The "evolution," as the president calls it, mirrors a sea change in national public opinion.
"I think that the same evolution that I have gone through is an evolution that the country as a whole has gone through," Obama said. "I think it is a profoundly positive thing."