By Sam Youngman
CHARLESTON, South Carolina (Reuters) - Mitt Romney is still the frontrunner for the Republican presidential nomination, but if he wins the South Carolina primary on Saturday, he might be limping across the finish line.
Romney turned in another uneven debate performance at best on Thursday, failing to keep main rival Newt Gingrich at bay and again making remarks that suggest he is out of touch.
The debate came after a bad few days, with his poll numbers dropping in South Carolina and Texas Governor Rick Perry endorsing Gingrich after giving up his own presidential bid.
Romney was way ahead in polls in South Carolina until a few days ago but Stuart Stevens, one of his top aides, sought to play down expectations late on Thursday night.
"I mean the idea should be, does he have a chance in South Carolina?" Stevens said. "These things are always going to close. I think it's very competitive."
Romney has suffered through a number of awkward debate moments, from his proposed $10,000 bet to Perry to Thursday night's claims that he is "from the real streets of America."
At one point in the debate, Romney, seemingly flustered by an attack from rival Rick Santorum, used the term "Romneycare," a derogatory name Republicans have given to healthcare changes Romney put in place when he was governor of Massachusetts.
Romney took fire from rivals Gingrich and Santorum on his conservative credentials and his record on healthcare.
When the issue of Romney's undisclosed tax returns came up, as it has repeatedly in the last week, there were a smattering of boos from the crowd when Romney held fast to his intention to release his returns in April.
Visibly irritated by the crowd reaction, Romney declared flatly: "I'm not going to apologize for being successful."
Pressed by moderator John King of CNN on whether he would release multiple years' tax returns, Romney first answered "maybe," then changed his response to a "yes."
Adam Temple, a South Carolina-based Republican consultant, said Romney needs to come up with a better way to handle questions about his taxes. "That's going to continue to be an issue until he puts it to bed," Temple said.
His lackluster debate performance could not have come at a worse time for Romney, who in the last two days has seen his South Carolina lead evaporate and his narrow victory in the Iowa caucuses reversed in favor of Santorum.
Romney, however, has a campaign organization that is vastly superior to that of his rivals and gives him an advantage in the following primary race in Florida.
Still, Romney's run to grab the Republican Party nomination to oppose President Barack Obama in November, thought inevitable a few days ago, is now less certain.
"Romney is still playing it safe and can't seem to connect with regular people to close the deal," said Republican strategist Mark Pfeifle.
(Editing by Todd Eastham)