{mosads}In New Hampshire, the Insider Advantage poll has Romney in the lead with 31 percent, but Gingrich follows within the margin of error at 27 percent. Over the weekend, the state’s influential conservative paper the Union Leader endorsed Gingrich, although Romney is still widely expected to take the Granite State, where most polls show him carrying a healthy lead.

But in South Carolina, an Insider Advantage poll conducted for the Augusta Chronicle has Gingrich crushing the rest of the GOP field with 38 percent of likely voters polled. Romney is second with 15 percent, followed by Cain with 13 percent, Paul with 7, Perry with 4, Bachmann with 3 and Santorum at 2 percent.

South Carolina will be critical to the Gingrich campaign, as it follows Iowa and New Hampshire on the Republican primary calendar, and most expect Romney to run away with a New Hampshire victory.

Gingrich is on a three-day swing through the Palmetto State, where he unleashed a number of sharp attacks against Romney. Gingrich pitched himself as the “conservative alternative” to Romney, and accused the former Massachusetts governor of flip-flopping on issues for political gain.

“I wouldn’t lie to the American people,” Gingrich told WSC Radio in Charleston, S.C., on Monday. “I wouldn’t switch my positions for political reasons.”