(CBS News) -- The socially-conservative men and women who are gathering in Washington, D.C. for the annual Faith & Freedom Conference Thursday are strong advocates of traditional marriage who have been highly critical of President Obama's endorsement of same-sex marriage.
But when it comes to presumptive Republican presidential nominee Mitt Romney, they aren't necessarily opposed to a marriage of convenience.
"At this point, I've got to feel comfortable with him," said Family Research Council President Tony Perkins, who will speak at the three-day conference on Saturday.
"There's the choice before us of Barack Obama or Mitt Romney. There are no other choices as I see it," Perkins continued. "He wasn't the first choice but I look at what he has to offer as opposed to what Barack Obama has to offer, and I'm for Mitt Romney."
Perkins is among the social conservative leaders who decided at a January meeting in Texas to throw their support behind Romney's then-rival Rick Santorum - in part out of fear of Romney as a standard-bearer for the Republican Party. They worried that they could not trust the former moderate Massachusetts governor, who Santorum derided during the primary as having "one of the most liberal records" of any Republican presidential candidate in recent history, to stand with them on issues like abortion, same-sex marriage and the relationship between religion and government.
And while the social conservatives gathering for the conference have largely made peace with Romney, who will speak to attendees via video conference on Saturday, they're not exactly bursting at the seams with excitement about his coming coronation at the Republican National Convention.
"Enthusiastic would probably not be the right word," said Jim Garlow, pastor of the evangelical California mega-church Skyline Church, who will address the conference Saturday.
Garlow said that he is backing Romney, in part, because he sees President Obama's policies as "catastrophic." But he adds that "there's simply a number of people who are waiting on the sidelines waiting to hear if there's convictional, visceral commitment" to social conservative positions. Support for Romney among evangelicals and conservative Catholics, he says, is "tepid at best."
More than one in three Americans identifies as conservative on social issues, and this group overwhelmingly supports Romney over Mr. Obama. But without high turnout from social conservatives in November, Romney will have a hard time competing in swing states such as Virginia, where he needs as many voters as he can find in the southern part of the state to offset a large advantage for Mr. Obama in the north. For that reason, Romney must continue courting skeptical social conservatives even as he tries to reach out to more moderate voters who do not share their views.
For the conservatives who will be speaking at the Faith & Freedom Conference, the most important question at this point is who Romney will tap as his running mate.
"He has publicly and privately communicated that his running mate will be a pro-life conservative," said Perkins. "The only thing that I've asked - pro-life, that's a pretty broad category. I would say that 90 percent of Republicans are pro-life. But have they actually done anything to advance the cause of life?"
"His running mate is going to be beyond somebody who has just checked boxes," he said. "They have to have had a track record of having worked toward these things."
Asked who he would like to see on the ticket, Perkins said that he was reticent to mention names because "that could take them off the list," since the Romney campaign doesn't "want to be seen as social conservatives pulling their strings." But he went on to name two men: Gov. Bobby Jindal, R-La., and former Gov. Mike Huckabee, R-Ark., who Perkins said is "probably much more popular now than when he ran for president."
Ralph Reed, the Founder and Chairman of the Faith and Freedom Coalition, said that Romney "is doing a fine job of building bridges to conservative voters and activists, including social conservatives." He pointed to Romney's recent speech at Liberty University and his willingness to participate in seven forums with Reed's group.
"We've had a very good relationship with him throughout, but he's still got some work to do and he knows that," said Reed. The former Christian Coalition executive director said that he expects Romney to pick "a full spectrum conservative" as his running mate, and that once he does, "you can expect to see social conservative enthusiasm, engagement and intensity gradually increase."
"People are genuinely frightened at the prospect of a second Obama term, and I think they believe that Romney has demonstrated a sufficient level of commitment to core conservative principles and is running a sufficiently competent campaign that they're coming on board," he said. "That's going to be a process - it doesn't happen overnight."
As a Senate candidate in 1994 in Massachusetts, Romney said he believed abortion should be "safe and legal." He now says he is strongly opposed to abortion rights. Penny Nance, the president of Concerned Women for America - a group that "promotes Biblical values and family traditions" - said Romney's earlier position had been a concern for her.
"But I do think he has gone above and beyond the call of duty to try to be very clear on where he is today," said Nance, who speaks to the conference Saturday. "You have to take a candidate at their word which is why you have to get a candidate on the record as to where he stands. I do think it would be a different thing, frankly, if I saw him parsing his words or backtracking. I haven't seen that."
According to Perkins, Mr. Obama's decision to endorse same-sex marriage has "helped tremendously" in driving up enthusiasm for Romney among social conservatives. "I think that gets the enthusiasm needle to about 75 or 80 percent, but I think Mitt Romney's going to have to help to get it a good way further," he said.
"There's no question that Mitt Romney as governor had some positions that were inconsistent with social conservative values...so there's some question as to can we really trust him," Perkins added. "I'd say look, we can trust Barack Obama to do what he has done for the last three years, and it is everything that is counter to what conservatives want in this country. And so I think people are going to come to the decision that we have to support Mitt Romney because we have to see change come to the country."
Brian Montopoli and Lucy Madison, CBS NEWS