( CNN ) -- Last week , Barack Obama went on record as the first American president to support same-sex marriage , but he does n't appear ready to take his commitment beyond the endorsement stage . In an interview that aired Tuesday on ABC 's `` The View , '' Obama would n't commit to fighting for the the repeal of the Defense of Marriage Act -- a federal law that defines marriage as the legal union between one man and one woman . `` My Justice Department has said to the courts , we do n't think the Defense of Marriage Act is constitutional , '' the president said . `` This is something that historically had been determined at the state level and part of my believing ultimately that civil unions were n't sufficient . '' But pressed further about whether he would fight to repeal DOMA , Obama would only say , `` Congress is clearly on notice that I think it 's a bad idea . '' More than 30 states have voted in favor of constitutional amendments that defend the traditional definition of marriage as a heterosexual union . The president does see the issue looming large in the 2012 election . `` This is going to be a big contrast in the campaign , because you 've got Gov . ( Mitt ) Romney saying we should actually have a constitutional amendment installing the notion that you ca n't have same-sex marriages , '' Obama said in the interview , recorded Monday . Last week , Romney reaffirmed his position on gay marriage , saying marriage `` should be a relationship between a man and a woman . '' `` Let me make it very clear , that my preference is to have a national standard that defines marriage as a relationship between a man and a woman , '' Romney said . `` That would then allow states to determine what rights would be provided for people of the same gender that wanted to have a relationship . '' While the full political implications of the president 's same-sex marriage statement remain to be seen , Gallup released a poll Friday showing 51 % of Americans approve of Obama 's support for allowing gay couples to marry , while 45 % disapprove . The survey was conducted entirely after he announced his endorsement in an ABC News interview on Wednesday . And a new Gallup poll out Monday gave further details into American attitudes on the topic . While 50 % approve of same-sex marriage , a further breakdown of the numbers shows a significant gender gap : 56 % of women say couples of the same gender should be legally allowed to marry , while 42 % of men feel the same way . This is Obama 's fourth appearance on `` The View '' and his second since taking up residence in the White House .
Poll : 51 % of Americans approve of President Obama 's support for same-sex marriage . This issue is going to be a big contrast in the 2012 campaign , Obama says . Score: 7 This is Obama 's fourth appearance on `` The View ''