Saw a clip or two from Romney's Mormon speech. It rated a resounding, "So what?" He was deliberately copying John Kennedy's speech to Protestant clergy in 1960, but he was missing the point. Reassuring the public that Mormon leaders won't influence his decisions in the White House reassures them over something they weren't uneasy about.
In 1960, a lot of folks were uneasy with the thought of a Roman Catholic President. No doubt a lot of that was mere bigotry, but the linchpin of the objection was the idea (right or wrong) that the Pope and his hierarchy command the faithful in such a way that an RC Prez would be a tool for some Italian prelate. JFK sought to dispel those fears, and largely succeeded. Such an idea is no longer an issue, especially in this day and age where many prominent RC pols routinely thumb their nose at the moral positions advocated by their Church.
But fears of undue influence are not what queasiness about a Mormon President is all about. When you get right down to it, an awful lot of people just think that Mormonism is weird, and they wonder about the intellectual equipment of anybody who sincerely believes it. It would be the same if we had a President who believed in Astrology or Spiritualism. Lots of people dabble in those things, but we would have doubts about a Presidential candidate who was in earnest about them.
In the end, Mitt very carefully and thoughtfully addressed the concerns that nobody had, so that he could claim to have addressed the concerns that people do have. "Hey, I gave that speech. Whaddya want? Why are you picking on the Mormon, huh?" As a carefully nuanced, rhetorically balanced attempt at misdirection, it is emblematic of his run for the White House.