Why would any Christian zealot be on a list of candidates in the GOP? Romney is a Mormon to the core and the Prophet in the Temple in Salt Lake City will be the leader of America within a week.
Reminds me of the arguments that were used in 1960...
Mormonism is far less prevalent than Catholicism among the American population, so it would resonate amongst the prejudiced than it did then.
You can't underestimate the power of bigotry. Mormonism certainly isn't a plus among the GOP base, and indeed probably hurts Romney. While that is not the reason that I would vote against him (my reasons to vote for Obama in this case are beliefs and the fact that he isn't the political chameleon that is Romney), it probably is a large factor in many states.