Here's some interesting graphics. First, the Iowa counties Mike Huckabee won in blue, those Mitt Romney won in red:

Next up, the proportion of Catholics in each county:

That's circumstantial evidence that Catholics don't like the Huckster. Philip Klinker, who put those images together, ran the numbers more rigorously and came to a firmer conclusion -- Catholics don't like the guy.

At the end of the day, that's big trouble. One thinks, traditionally, of white (?) Catholics as the core bloc of culturally traditionalist voters with some leanings in the direction of economic populism. Any nationally successful coalition founded on the sort of Christian Democratic approach that Huckabee gestures at in his more appealing moments would need to have Catholic voters at its heart, not pushed out to the margins.