President Obama is remaining on the sidelines in the gay marriage debate, even as a California federal appeals court on Tuesday declared the state’s anti-gay marriage Prop 8 referendum unconstitutional, likely setting up a U.S. Supreme Court decision on the issue.

At a press conference Tuesday at the White House, Obama’s press secretary, Jay Carney, called gay marriage bans “deliberate efforts to deny benefits.” But he said Obama’s stance on the issue has not changed.

The president, who opposed gay marriage during his 2008 campaign, said in 2010 his position is “evolving” on the issue, and has said little since then. Some gay rights activists are pushing the president to give a declaration of support for same-sex marriage, as many liberals and conservatives believe that is his private position.

WATCH MSNBC COVERAGE OF THE PROP 8 RULING:

Visit msnbc.com for breaking news, world news, and news about the economy

Obama’s support of gay marriage would mean little in practice. Marriage laws are determined by each state, not the federal government, and the president also has little say in the Supreme Court’s decision.

But his words could have an impact on the issue, in part because of the president’s influence in the African-American community. According to exit polls, about 70 percent of black voters in California supported the gay marriage ban that passed in 2008.

Politically, it’s not clear what impact it would have if Obama embraced gay marriage before the 2012 election. It could potentially galvanize young voters, who largely back gay marriage. Voters under 30 are already firmly behind Obama, but polls show they are not as energized as four years ago and might choose to stay home on Election Day.

On the other hand, voters over 60, which polls show largely oppose gay marriage, could be moved to oppose the president if he comes out in favor of gay marriage.

Follow Perry Bacon Jr. on Twitter at @perrybaconjr