WASHINGTON -- An unexpected surge in support to place same-sex marriage on the Democratic Party platform at the August convention has energized LGBT advocates and complicated an already delicate situation facing President Barack Obama’s reelection campaign.

In the past month, almost half of all Democratic senators, several of Obama's national campaign co-chairs, the House Minority Leader and the chairman of the Democratic convention, among others, have said they support adding marriage equality to the platform. Were this the position that the president held, such proclamations would not be a problem. But Obama says he is still publicly “evolving” on marriage equality. And the wave of support to make it a component of his convention has both surprised aides and set off a private push to keep emotions and expectations in check.

Interviews with more than a dozen party officials and activists reveal that despite widespread and growing support for marriage equality among Americans, the issue is still viewed as politically sensitive in the top ranks of the Democratic Party. While many high-profile figures have publicly advocated for including strong language in the platform, the Obama campaign and the allied Democratic National Committee are searching for ways to split the difference: showing support for equality but stopping short of a full-fledged endorsement.

Publicly, this friction has yet to surface. During a conference call with reporters on March 7, Obama Campaign Manager Jim Messina avoided the matter, saying that all decisions would be made by the convention’s platform committee, whose members had yet to even be chosen.

“There's a process,” he said, “and the DNC will go through that, and we will have a platform.”

Behind the scenes, however, there are concerns that expectations surrounding the platform’s language are moving beyond electoral feasibility. Those concerns peaked when Los Angeles Mayor Antonio Villaraigosa (D), who is the chair of the convention, responded affirmatively when asked whether he thought the platform “should have a marriage equality plank."

“I do,” he replied. “I think it’s basic to who we are. ... I don't think the government should be in that business of denying people the fundamental right to marry.

That Villaraigosa would publicly support same-sex marriage was not a surprise; he is co-chair of the group Mayors for Freedom to Marry. It was the timing of the remarks that caught Obama insiders off guard. Within a few days, Villaraigosa was offering a more lawyerly position.

"It is up to the delegates of the Democratic Party to draft the Democratic Party platform," he told the Sacramento Bee in a wide-ranging interview. "Our delegates will put the platform together and I suspect it will be very inclusive.”

A spokesman for the mayor said Villaraigosa stands firmly by his belief that marriage equality should be part of the platform and is continuing to make clear that the platform language will go through the platform committee and will ultimately be voted on by all the delegates. But other sources told The Huffington Post that the DNC has been asking advocates for patience, worried that more sweeping platform language would put the president in an awkward bind.

"The DNC folks -- their political shop -- have been calling people and really pressuring them," said Paul Yandura, a political and fundraising strategist at the firm Scott+Yandura who led gay and lesbian outreach on both Bill Clinton and Al Gore's presidential campaigns. "Look, I'm not going to claim that they're pressuring them not to be for it, but this 'let's wait' thing is always what happens in politics -- let's wait so they can find a way to slow this down and maybe get a good reason not to do it."

"But that doesn't mean that activists and other people have to wait and see," Yandura added. "I think that we have to keep up the pressure."

Melanie Roussell, a spokesperson for the DNC, did not directly refute Yandura's assertion. Instead, she emphasized the party's commitment to equality and inclusion, with respect to both LGBT Americans and the platform process.

"The President and the Party are committed to crafting a platform that reflects our values and a belief that this is a nation in which everyone deserves a fair shot and hard work is rewarded," she wrote in an email to The Huffington Post. “The time will come to consider the content of the platform but not a single platform committee member has been chosen and the process has yet to begin."

Several Democratic sources working with the committee have acknowledged that conversations were already underway about how to placate the pro-same-sex marriage majority inside the party without alienating culturally conservative Democrats in states like Ohio and North Carolina, where the convention is being held.

“Everybody wants marriage and everybody wants the president to win. Those two things are easy,” one of those sources said. “The only question is what language do you use?”

Finding an answer to that question has already proved difficult for top Obama aides, many of whom have personally experienced the fury of gay groups scorned. In 2008, the Democratic Party platform stopped short of embracing same-sex marriage but stated, "We oppose the Defense of Marriage Act and all attempts to use this issue to divide us."

This year’s version, according to sources familiar with early conversations, will likely emphasize the accomplishments made under the president, such as a refusal to defend DOMA, the decision to grant same-sex couples visitation rights in hospitals, and the repeal of Don't Ask, Don't Tell. As for the specific issue of marriage equality, no formal meetings have taken place. Yet several variations of new language are already being envisioned, ranging from text that would underscore the need for inclusive employment, non-discrimination legislation and safer schools, to language that would emphasize the benefits of relationships regardless of sexuality, to a platform that championed marriage equality outside the religious realm.

“If the word marriage is used, then I'm all but certain that there will be something very explicitly saying civil marriage and that this has nothing to do with religious marriage,” said the Democratic source working with the DNC, adding that the hoped-for additions may come at a future convention. “It is possible that there will be one more time without using the word."

Leading the effort to beef up the platform language on marriage equality is Freedom to Marry, a pro-LGBT rights group that launched a "Democrats: Say I Do" campaign on Feb. 13. The group has proposed platform language that explicitly says the Democratic Party endorses the "freedom to marry” and has been working behind the scenes to solicit support among Democratic officials. It also employs Joel Benenson, a top Democratic pollster whose client list includes the president’s campaign.

"Obviously the candidate has a big role in it, and it's important as part of helping position the candidate, but it's also about helping to shape the party and the forward momentum of the party and moving the country forward," said Evan Wolfson, Freedom to Marry’s founder and president.

Among interest groups pushing marriage equality as a platform issue, Freedom to Marry may be playing the most active role. But its success has been facilitated, in part, by help from several strange-bedfellow allies and a political climate that’s proved more advantageous than even the most optimistic LGBT activist could have predicted.

Third Way, an influential centrist Democratic group, has pushed polling data instructing lawmakers how best to pass marriage equality laws across the nation. Labor groups, who were disengaged from earlier fights, have put their get-out-the-vote resources behind stopping anti-marriage initiatives in specific states. The December 2010 vote to repeal Don’t Ask, Don’t Tell demonstrated to lawmakers that they would sustain little damage for casting pro-gay rights votes. Some even saw unexpected benefits, including both Republican and Democratic state senators in New York who were rewarded, in the form of campaign donations, for legalizing same-sex marriage in the state.

But while the climate seems ripe for the party to make a big statement at the convention, others have urged caution. Maryland Gov. Martin O’Malley (D) exemplifies the uncertainty. Despite having recently signed a law legalizing marriage equality in his state, he said he had concerns that promoting it nationally would distract from an economy-centric message.

“I don't know,” O’Malley replied, when asked if equality should be on the platform. “I think the most important thing that we need to do at the convention is stay focused on jobs, focused on the economy, focused on opportunity and making the right decisions now.”

Among other officials, meanwhile, the case is already being made that the platform itself is not entirely important. The DNC's Roussell called it a "visionary document, not a check list." Others have made a similar case, arguing that it more closely represents a set of symbolic goals than a declaration of principles.

“I can't speak for the White House or the president. I think there are some people for whom it would be a problem [if marriage equality was included] because it isn't lock-step where the president is in his evolution today,” said Dana Perlman, a party fundraiser and board member of the Human Rights Campaign. “But it does set an aspirational goal for where the president will be.”

Winnie Stachelberg, who as executive vice president for external affairs at the Center for American Progress works closely with the White House, predicted that even the act of adding marriage equality to the party platform would do little to affect the president’s movement on the issue.

"I think he's on his own timeline, as are millions of other Americans, and I don't think his own thinking depends on where the platform is or ends up, and vice versa," she said.

Disagreements over how to approach the platform have quietly played out within the DNC LGBT Caucus as well. Debates have taken place over email and, most recently, on a Feb. 27 conference call among the members, who remain divided over whether to endorse specific platform language right away or hold off until closer to the convention.

"I think that making noise around the subject has the potential to be a distraction to some of the other things that Democrats are working on -- namely, what is the biggest priority for Democrats around the country, which is jobs and the economy," said one caucus member. "It's not about whether the caucus does this, it's about when the caucus does this."

HRC President Joe Solmonese sounded a similar note. "What I think is happening now is that there is a real effort to demonstrate how many people in the Democratic Party are supportive of this," he said. "That in and of itself is a significant development."

Publicly, the LGBT caucus has so far refused to take a stand one way or the other. "I support the inclusion of marriage equality within the Democratic Party platform, and I believe that every member our caucus does also," said Rick Stafford, who chairs the caucus. "However, the caucus, officially, will at some point weigh in on this and other LGBT community issues.”

The process of actually putting together a platform is an exercise in arcane bureaucracy. A total of 161 delegates will make up the platform committee, with representatives from all the states and territories selected by June 23. They will receive instructions from a 15-member platform drafting committee, which, in turn, is put together by DNC Chair Debbie Wasserman Schultz (D-Fla.) in consultation with platform committee leadership. That committee will solicit advice from allied groups and voters when composing its first draft. But throughout the process, the Obama campaign will have what one convention official described as “the right of review.”

All of which suggests that, despite Messina’s strategic vagueness, the platform will only go so far as the president wants it. The question then becomes: How far is that?

For many in the LGBT activist community, skepticism on this front is justified. The president’s evolution -- already in contradiction to the support he expressed for marriage equality as a state senator -- would confound even Darwin at this juncture. But not everyone is willing to rule out convention-floor or election surprises on the marriage equality front.

“I find it impossible to believe that this presidential election will be completed without Barack Obama coming out strongly for marriage equality and Mitt Romney coming out strongly against it,” said Hilary Rosen, a longtime party strategist who is deeply involved in LGBT causes. “I think it would be hard for him to not take a position."

This article previously reported that Los Angeles Mayor Anthony Villaraigosa is co-chair of the group Mayors for Marriage. The group's official name is Mayors for the Freedom to Marry. The comments of Villaraigosa's spokesman were also updated.