WASHINGTON (Reuters) - Republican presidential hopeful Newt Gingrich is gaining ground in South Carolina, but rival Mitt Romney still leads in the state by a 12-point margin and would beat the former lawmaker handily in a one-on-one race, according to a Reuters/Ipsos poll.
The poll, conducted of 656 likely voters in Saturday's Republican primary contest in the state, showed Romney with 35 percent support, Gingrich with 23 percent support, and former Senator Rick Santorum with 15 percent support.
Congressman Ron Paul came in with 13 percent support and Texas Governor Perry, who was still in the running when the poll was taken, had 6 percent. Perry dropped out of the race on Thursday and endorsed Gingrich.
Accused in attack ads of being a Washington insider, former House of Representatives Speaker Gingrich had poor showings in the first voting states of Iowa and New Hampshire, but he has fought his way back into contention in South Carolina.
A strong performance in a televised debate with all of the candidates on Monday helped Gingrich, and Thursday's departure of fellow conservative Perry is also likely to give him a boost.
A Reuters/Ipsos poll last week showed Romney with a 21-point lead over his nearest rivals Paul and Santorum, and overall support of 35 percent from registered Republicans. Gingrich came in at a low 12 percent support.
The latest poll was conducted of likely voters - not just registered voters - from both parties. South Carolina does not require people to be registered with a party to vote.
It was conducted January 16-18, so the first day of data collection took place before the Monday evening debate.
"Newt Gingrich is performing pretty well with this group but not well enough to really win the state," Ipsos pollster Chris Jackson said. "Even with Rick Perry's support, it's not going to be enough to put Newt Gingrich over the top."
Asked if the contest came down to Romney and Gingrich, 54 percent of respondents said they would vote for the former Massachusetts governor, while 33 percent said they would back Gingrich.
Because the poll was conducted online, statistical margins of error do not apply, but this poll has a "credibility interval" - similar to a margin of error - of plus or minus 4.5 percentage points for each candidate's result.
Romney has had a tough week. After originally being declared the winner of the first nominating contest in Iowa, officials revised the outcome to show Santorum had won.
The former business executive also took heat from his Republican rivals for his reluctance to release his tax returns.
Romney has signaled he would probably release his latest return in April, but his revelation that the tax rate he pays was close to 15 percent gave fuel to his opponents and the White House to paint him as out of touch with ordinary Americans' circumstances.
Gingrich's debate performance on Monday gave him momentum for a portion of the week, but he faced a series of attacks as well.
His ex-wife Marianne Gingrich said in an interview released on Thursday that he had wanted an open marriage, in comments that could hurt the former speaker's standing with religious conservatives in South Carolina.
Gingrich is now married to his third wife, Callista, with whom he was having an affair while married to Marianne. Since the affair he has converted to Catholicism and says he has asked for God's forgiveness.
Editing by Philip Barbara