I would like to think that if Romney doesn't win the Republican nomination, it is because others saw his betrayal of the principles of this country and rejected him for it

Yeah, but consider his audience. That speech was all about convincing the Christian conservative base of the Republican party that Mormonism isn't a cult, and that he's committed to their goal of keeping religion tied to politics. If anything, I think that speech may bring him closer to the nomination.

As for the JFK reference, there were far more Catholics in this country when he gave that speech, than there are Mormons today. Romney has a lot more people to convince than JFK did.