I think Jan Krakauer nails it:
JFK’s speech was to reassure Americans that he wasn’t a religious fanatic. Mitt’s was to tell evangelical Christians, ‘I’m a religious fanatic just like you.’
The above quote is from Maureen Dowd’s article, Mitt’s No JFK. I agree with her, of course. Just read this claptrap, from Romney’s speech:
Freedom requires religion just as religion requires freedom. Freedom opens the windows of the soul so that man can discover his most profound beliefs and commune with God. Freedom and religion endure together, or perish alone.