The fourth poll released during the past three days shows former Mass. Gov. Mitt Romney with a significant lead in South Carolina.

The Public Policy Poll shows Romney with 30 percent support in the state, followed by former House speaker Newt Gingrich at 23 percent and Sen. Rick Santorum at 19 percent.

No other candidate polled in double-digits.

Romney's lead looks even more daunting when the polls dives deeper. 67 percent of Romney's supporters said they would definitely vote for him, which is the highest percentage of any candidate.

Despite Gingrich's second place position, analysis released by Public Policy Polling suggests Santorum has a better chance to beat Romney.

According to the analysis:

     [Santorum] edges out Romney as the candidate with the best favorability rating at 63/21. We tested hypothetical head to head match ups between Romney and the other leading Republican candidates in the instance that were some drop outs before the primary. Romney defeats Gingrich handily in such a match, 49-35.  But Santorum runs only slightly behind Romney at 45-40.

The poll suggests that the best chance for anyone other than Romney to win the primary would exist if the field thinned, leaving supporters of candidates like Gingrich or Gov. Rick Perry free to support Santorum.

Interestingly, the poll also asked voters whose endorsement would make the biggest impact on their decision. 31 percent of voters said a Jim DeMint endorsement would make them more likely to vote for a certain candidate, which was more than twice as many as any other potential endorser.

As endorsements go, those surveyed said Gov. Nikki Haley's and Sen. John McCain's had little effect on their choices. For McCain, 11 percent of respondents said his endorsement made them more likely to vote for Romney, while 30 percent said it made them less likely. Similarly, 14 percent of voters said a Haley endorsement would make them more likely to vote for Romney, while 25 percent said it would make them less likely.

The poll also had a little fun, taking Stephen Colbert's role and asking voters whether "corporations are people" or "only people are people."

Supporters of all three frontrunners were more likely to say that "corporations are people," while supporters of candidates like former Utah Gov. Jon Huntsman and Rep. Ron Paul said only people were people.

Supporters of the top-3 were also more likely to find Colbert unfavorable. Almost 30 percent of Gingrich and Romney supporters said they did not like the South Carolina-born comedian.

All four polls released this week show Romney leading, with either Gingrich or Santorum running second and third.

South Carolina polls are famous for fluctuation, and the Public Policy Polling anaylsis suggested the same could be true in 2012:

     Finally it's important to note how truly up in the air the South Carolina race is. 45% of voters are either undecided or open to changing their minds in the next two weeks. And when we asked folks who they thought had run the strongest campaign in the state 49% said they weren't sure, speaking to the fact that the campaign there really hasn't started yet. Romney's in the lead for now but a Gingrich or more likely Santorum surge certainly seems within the realm of possibility.