A near-panic has taken hold among some core conservative activists, who are now scrambling to devise a strategy to deny Mitt Romney the Republican presidential nomination.

Many of these activists see South Carolina’s primary on Jan. 21 as their last best hope of stopping Romney by consolidating in a united front against him. But many acknowledge that they have yet to figure out which of the remaining conservative rivals to rally behind and which should get out.

The tension is exacerbated by the deep divisions between two key GOP wings: tea party groups yearning for a pure small-government conservative, and evangelical Christians who want a loyal social conservative.

In one sign of their desperation, some activists are holding out for what they acknowledge is a spectacular long shot: a late-entering savior who could still qualify for enough state ballots and win enough delegates to force a brokered GOP convention this summer.

The Romney conundrum will be on the agenda Friday when about 150 evangelical leaders huddle at a Texas ranch to debate their next move. Likewise, the subject of consolidating conservative opposition to the former Massachusetts governor is expected to be a major point of discussion among about 500 attendees at a tea party convention set for this weekend in Myrtle Beach, S.C., where the list of speakers includes two Romney rivals seeking the conservative mantle, Newt Gingrich and Rick Santorum.

“We’re aware that the vote is being split and how dangerous that is,” said Joe Dugan, a Gingrich supporter who is chairman of the Myrtle Beach Tea Party and coordinator of the convention.

“We’re trying to encourage coalescing around one candidate,” Dugan added. “But tea party people are very independent-minded.”

One participant in Friday’s evangelical meeting, the Rev. Jim Garlow — pastor of a San Diego megachurch and a leading champion of California’s anti-gay-marriage initiative — said Romney is “untrustworthy” and not “ visceral on the issues that are cardinal to me.”

“I’m not in panic mode, at least not yet,” said Garlow, one of Gingrich’s most prominent evangelical backers. “There’s still time, although the fuse is short.”

The fretting from conservatives reflects a persistent question about Romney’s candidacy: whether a wealthy private-equity executive with a history of centrist views in a liberal state can gain the trust of the most energized and active elements of the GOP’s conservative base. And now, a series of attacks on his record at Bain Capital threatens to undercut Romney’s main argument to conservatives: that his private-sector experience best positions him to defeat President Obama in the fall.

Many social conservatives worry about his past support for abortion rights (he has since declared himself antiabortion), and some are wary of his Mormon faith. Meanwhile, many tea party activists say Romney’s background in finance and his support for the Wall Street bailout are reasons for skepticism.

Until now, Romney and his campaign have seemed content to pursue the nomination by showcasing his establishment credentials.

But there are signs that the campaign is shifting to try to head off growing concerns. Romney has sharpened his rhetoric, now regularly borrowing a line from Sarah Palin to rail against “crony capitalism,” a term that refers to companies that use political connections to score government aid and tax breaks.

Such language is a decided departure for Romney, who has forged close ties with corporate America but now must reconcile his image as the chamber-of-commerce candidate with the anti-Washington fervor animating much of his party’s base.

The shift follows meetings in recent months between the candidate and some national tea party activists.

Sal Russo, a strategist for the Tea Party Express who met with Romney aides in April, described a “misunderstanding as to what the tea party stood for.”

But he added: “I think they understand now that the tea party movement is a very broad-based movement, and one that is very consistent with Governor Romney’s core beliefs.”

Romney adviser Kevin Madden called the new tone “a convergence of priorities” as the former governor hones a small-government, cut-spending message long embraced by the tea party movement.

“Now that we’re looking for a candidate to carry that message banner, you’re seeing the message in a way meeting the movement and the movement meeting a candidate’s message,” Madden said.

Romney campaign aides and supporters concede that the candidate has not yet made the sale, but they say he will win over conservative voters. They point to the support of a tea party favorite, South Carolina Gov. Nikki Haley (R), who is campaigning nationally for Romney.

“We have a lot of work to do in South Carolina in the next 10 days, but we are proud of all of the strong support we have from conservatives like Governor Nikki Haley,” said Andrea Saul, a Romney spokeswoman.

Polls have shown Romney performing less well than other GOP candidates among evangelical and the most conservative Republican voters. His aides are likely to point to Tuesday night’s exit-poll results from New Hampshire to show improvement with the Republican base, including his winning tea party supporters by a wide margin and topping Santorum among evangelicals.

Still, national and South Carolina-based activists said Romney has a difficult task in unifying the party base.

Many social conservative leaders are still seething over the party’s experience in 2008, when evangelical Mike Huckabee won the Iowa caucuses but the base didn’t unite, and John McCain locked up the nomination early.

“We made a terrible mistake in 2008,” said Richard Land, president of the Southern Baptist Convention’s Ethics & Religious Liberty Commission.

Another evangelical leader, Gary Bauer, who endorsed San­torum, said that “the longer that there are multiple candidates, the easier it will be for any front-runner, and that’s certainly the case for Romney.”

Several tea party activists on the ground in South Carolina said they had yet to receive any outreach from the Romney campaign. And several said the endorsement by Haley angered some of her biggest supporters, who see her decision as a repayment for the financial support that Romney provided her 2010 campaign.

It was “payback, and that’s kind of what we’re against,” said Joe Thompson, head of a tea party group in York County, in northern South Carolina.

“I’m sure she had her reasons, but I wouldn’t have picked him,” said Janet Spencer of North Myrtle Beach, chairman of the Carolina Patriots group.

Matt Kibbe, president of the pro-tea-party group FreedomWorks, said his organization has a super PAC that has raised about $2 million and could inject itself into the race to push a yet-undeclared candidate, such as Louisiana Gov. Bobby Jindal, who is backing a weakened Texas Gov. Rick Perry.

Kibbe noted that the qualifying periods for many later primary races will remain open for weeks — and that a new candidate could attract enough support to provoke a contested convention.

“In this more decentralized process, if Romney continues to create this vacuum by not consolidating 30 to 40 percent, the vacuum has to be filled,” Kibbe said. “If Newt or Santorum can’t do it, somebody’s going to do it.”

It is an admittedly unlikely scenario — many state ballot rules are complicated, and the concept of staging a convention battle ignores the reality that nominations are often won through momentum.

Among the candidates who remain, Romney’s critics can’t agree on who should get the nod. Gingrich backers are pushing for Santorum and Perry to drop out, while Santorum supporters see an obvious solution if Gingrich and Perry clear the way.

Complicating matters for the anti-Romney wing is a compressed campaign schedule that will allow him to gain momentum if he racks up victories, while the presence of super PACs provide a form of life support for candidates who might otherwise have to exit the race.

Some say the process may happen naturally after South Carolina votes.

“One of the things that causes people to drop out,” said Bauer, who ran for president in 2000, “is when the quality of hotel you’re staying in goes down every week, and you’re laying off staff.”