So it seems the Huckabee surge is thanks in part to evangelical anti-Mormonism. Not Huck's fault (unless you believe his latest ad is a subtle contrast with Romney on religious issues, a question Ambinder plumbs here). I think this futher argues for Romney to give a speech about his faith--or better yet, as I've suggested before, to hold an "Ask Mitt Anything" town hall where people can confront him with their concerns and common misconceptions and he can genially bat them down.
A major problem for Mormons is the common belief that they are hiding weird secrets, and thus openness and approachability is a virtue in itself for Romney here.
Update: Via Jonathan Martin I see that Mormon Orin Hatch seems to urging Romney to give a "JFK speech."
--Michael Crowley