Despite President Obama's vocal support for gay marriage this week, supporters and opponents know the real battle is likely to come in the court system where a pair of cases are widely expected to end up at the U.S. Supreme Court.
One case concerns California's passage of a citizen-initiated constitutional amendment banning same-sex marriage while the other challenges the federal law, known as the Defense of Marriage Act, which defines marriage as only between one man and one woman. The Obama administration made news earlier this year when it announced it would no longer offer a legal defense for DOMA.
But legal observers say the president's surprise public declaration of support for gay marriage may tangentially affect how the highest court ultimately rules.
"With his switch from ambivalence to advocacy, Obama is sending a signal to the courts that the country is ready for gay marriage, giving them more cover to uphold it," wrote Jonathan Rauch, a gay marriage supporter and guest scholar of Governance Studies at the Brookings Institution, in a statement following Obama's announcement. "Courts may not go by poll results, but they do like to stay within the mainstream. And Obama has just moved it."
Rustin Silverstein, managing director of legal crisis communications at Hamilton Place Strategies, says the president's words have no impact on the legal arguments before the courts or direct influence on justices, but agrees they still matter.
"For the Supreme Court in particular, I think the president's endorsement kind of legitimizes this and brings it into the mainstream more than anything else that's happened so far," he says. "As far as the court goes, although they try to be independent of public opinion, I think it's always something in the back of their minds particularly if they are going to make a change that's seen as a major shift in social policy."
Silverstein notes that Obama's remarks are also part of a larger context paving the way for a ruling in support of same-sex marriage.
"The combination of the poll numbers and Obama's support as well as, truthfully, prominent Republicans – Dick Cheney, Ted Olson arguing the case – shows that this is not a fringe position put forward by gay rights activists exclusively," he says.
Cheney, the vice president under Republican George W. Bush and father of a gay daughter, publicly endorsed gay marriage in 2009. Olson, who served as solicitor general under Bush and successfully argued the Bush v. Gore case before the Supreme Court, is one of the lead attorneys seeking to overturn California's ban on same-sex marriage.
James Essex, director of lesbian, gay, bisexual and transgender issues at the American Civil Liberties Union, calls the president's public statement a reflection of society at large.
"I don't think the president's decision to speak his mind on the issue of marriage for same-sex couples by itself changes court results that we'll see in the future but I think as part of a larger indicator it's a reflection of that public opinion has shifted so quickly and so substantially on this issue," he says. A recent Pew Research Center poll shows 47 percent of voters support gay marriage, up from 35 percent in 2001.
Both Essex and Silverstein say public opinion has likely influenced case outcomes in the past, thanks in part to the reaction to the court's 1973 decision that legalized abortion.
"A lot of legal observers think Roe vs. Wade was decided somewhat prematurely, that a lot of the states and public opinion was moving more and more in support of finding there to be a right to an abortion, but the court because they got there before public opinion did kind of led to a hardening of positions and then decades of social division over that issue," Silverstein says.
Essex adds, "You can look back at history and see that significant legal decisions in civil rights areas have often followed as opposed to led public opinion on the issue."
The court's make-up of four reliably liberal justices, four reliably conservative justices and Justice Anthony Kennedy, who often wields the deciding vote, also could make a ruling upholding same-sex marriage likely. Kennedy wrote the 2003 majority decision that struck down a Texas sodomy law, Lawrence v. Texas, which effectively made same-sex sexual activity legal in the United States, citing that the law violated the 14th amendment's due process guarantee. A similar argument is being made in the cases working their way forward.
"Kennedy is the wild card. He wrote the decision for the Lawrence case and although there he kind of equivocated a little bit about whether it would also apply in the marriage context, but things have changed now," Silverstein says. "If the composition of the court doesn't change dramatically, I think you see a reasonable possibility of a 5-4 decision in support of same-sex marriage."
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Rebekah Metzler is a political writer for U.S. News & World Report. You can contact her at email@example.com or follow her on Twitter.