First, of all, let me say that the recent ARG polls, strike me as a little weird. (I am suspicious of their likely voter model, especially in Iowa) My money is on these being outliers. Several things do occur to me though. First, the numbers:

Republicans IA NH SC
John McCain 26% 29% 36%
Rudy Giuliani 19% 17% 23%
Mitt Romney 14% 24% 6%
Fred Thompson 13% 7% 10%
Undecided 12% 14% 12%
Gingrich 8% 4% 6%

Romney does dramatically worse in South Carolina. These numbers do confirm what Gallup found about Romney’s performance in the South. He just does dramatically worse there compared to other regions. Also, Fred Thompson’s weakness in New Hampshire suggests a similar pattern.

In any case, we shall see.