Columbia, S.C. — Fighting to regain momentum in the South Carolina primary, Rick Santorum has shown little of the pizzazz that has characterized so many of the poll frontrunners this cycle.

“I may not be flashy and have a bunch of applause lines,” he admitted Tuesday, speaking at the Flight Deck restaurant in Lexington, S.C. “But what I’ve got is good, solid principles and I’m not changing my mind every ten minutes.”

In a navy sweater vest, his name embroidered on the upper right, Santorum earnestly and aggressively makes the case that he is the candidate around whom South Carolina conservatives should rally.

“South Carolina has a chance to nominate someone . . . who reflects their values,” Santorum says, speaking in a room papered with photographs of old military planes, to an audience clustered in booths and rows of chairs. “Don’t compromise.”

“The best chance to win this election is to not compromise,” he adds. “The country is looking for leadership. They’re not going to be looking for someone who can manage just a little better than the guy that’s in there now.”

Long before his Iowa surge, Santorum had shown at debates a willingness to go after his rivals. Now a top-tier candidate himself, he’s just as willing to throw punches. “Newt’s a friend of mine, but Newt is great in a think tank, coming up with a lot of different policy ideas, but as far as leadership, look at when the two of us were in leadership,” Santorum says, arguing that conservative organizations trusted him to fight for the issues they cared about from his perch in the Senate. In contrast, “three years into the speaker’s speakership, there was a conservative revolution against Newt trying to throw him out because he wasn’t advancing conservative [causes].”

As for Romney, Santorum argues that the former Massachusetts governor is “timid and, at best, inconsistent with respect to the issues we’re dealing with, and on the wrong side of many issues, like health care, the Wall Street bailouts, and global warming.”

Asked about Ron Paul, Santorum launches into an extended discussion of the differences between the conservative and libertarian outlooks on the Constitution. But at the end of his riff, he references Monday night’s debate, talking about Paul’s attempt to make a distinction between military spending and defense spending. “If someone can write me a memo on the difference, I’d appreciate that,” Santorum quips.

In Iowa, Santorum distinguished himself from the pack by pointing to his extensive retail politicking in the state, including visits to all 99 counties, a feat matched only by Michele Bachmann. In South Carolina, he has no such edge over his rivals.

And the chosen focus of his remarks, at least at this particular event, is perplexing. At the Lexington town hall, before opening up the floor to questions — usually a time when candidates deliver a brief sketch of their views on a wide range of issues — Santorum dives into a prolonged discussion of Social Security. He uses the topic as a way to distinguish himself from Romney and Gingrich, but he also delves deep into the details, rattling off factoids such as the percentage of seniors living below the poverty line, and musing on the fiscal benefits of pushing Social Security eligibility back just one or two months from age 62.

The questions after his remarks are wide-ranging, touching on topics from energy to immigration, and Santorum deftly handles them. Retiree Jane Flythe was struck by Santorum’s sincerity. “This man answers questions directly and right away,” she remarked. “You can’t always trust what everybody says. But I think he means it.” After commenting that she liked Gingrich, Flythe admitted she had lingering concerns about the former Speaker, saying she was “not comfortable with him because of his past and his changing his views.”