Ross Douthat makes a smart point that up until now I haven't seen anyone else make:
It's interesting that the Huck's rise coincides with Rich Lowry's provocative piece in the latest NR comparing Barack Obama to Jimmy Carter. As far as their skimpy resumes and "too good for politics" political styles go, the Lowry parallel is persuasive. As far as political trajectories, though, it’s Huckabee who has the more obvious Carter Redux thing going on: A pious, folksy, no-name Southern governor who rises steadily in the polls when all the putative front-runners turn out to be much more vulnerable than anyone expected. [Emphasis added.]
And don't forget that Carter was a pious, folksy, no-name Southern governor who used (in an unprecendented fashion, at the time) the Iowa Caucuses as a springboard to the nomination--which, of course, is exactly what Huckabee's trying to do.