Biden comments on same-sex marriage expose internal White House divisions As more top officials in his administration speak out in favor of same-sex marriage, Obama is facing increasing pressure to take sides in one of the most emotional and polarizing social policy debates of the modern era. The president has said his views are "evolving," but he has stopped short of the endorsements given by Duncan, Biden and Housing and Urban Development Secretary Shaun Donovan. Several people close to the White House said the episode has exposed internal tensions within Obama's team between those who want the president to say he favors same-sex marriage before the November election and others who worry about a political backlash if he does - not just among conservatives and working-class voters but among African Americans who are Obama's most loyal support bloc but tend to oppose such unions. About one in six of Obama's top campaign "bundlers" are gay, according to a Washington Post review of donor lists, making it difficult for the president to defer the matter. Activists are planning a campaign for the adoption of a pro-gay-marriage plank in this year's Democratic Party platform. And a series of referendums this year on same-sex marriage - including one in the swing state of North Carolina on Tuesday - are putting the issue at the forefront. "It's my understanding there are people in the campaign, the White House and the administration who are talking about what he will say if he is asked," said Winnie Stachelberg, executive vice president of the liberal Center for American Progress and a senior advocate in the lesbian, gay, bisexual and transgender community. The support from Biden and Duncan prompted Joe Solmonese, president of the Human Rights Campaign, to issue a statement declaring that there is "no doubt in my mind that the president shares these values" and calling on Obama to express himself. Richard Socarides, a prominent gay activist who was President Bill Clinton's top adviser on LGBT issues, said Monday that Obama and his team are "boxed in" on the marriage issue. "It's a problem of their own making," he said. "The president's "evolving strategy" could maybe work for them as a stopgap, but you can't be evolving on a significant national policy issue for two years, especially in a presidential election. I don't think it serves him well. Really, as a political matter, it's too cute. Strategists for presumptive Republican nominee Mitt Romney think that any sustained focus on same-sex marriage could help unite the conservative coalition behind his candidacy, particularly in key swing states such as Iowa, where the Republican Party remains deeply fractured after a bruising primary campaign.