If, on the other hand, I'm "exactly wrong" and Douthat is "exactly right," then Mitt Romney is truly screwed. What is he supposed to say about his religion? He can't do the JFK separation-of-church-and-state bit; he's in the wrong party at the wrong time of history for that approach. He can't educate evangelicals about the tenets of the LDS church; aside from being a complex endeavor, that would probably alarm listeners even more than their current vague suspicions about the Mormon "cult." So if he also can't even appeal to the deep cultural conservative consanguinity of Mormons with evangelicals, he might as well cancel the speech and hope for the best.
And, indeed, Romney does seem truly screwed. There's just no way to do what he's doing. Mitt Romney, Mormon, worked back when "Mitt Romney" denoted a culturally moderate politician. But he decided that a culturally moderate politician couldn't win a Republican Party presidential nomination, so he remade himself as a cultural conservative. But a culturally conservative Mormon is screwed outside of the Mormonism-heavy states of the West. And, obviously, the main driving force of his candidacy has always been the absence of alternatives who appeal to Christian conservatives anyway. He still has that going for him to some extent, so maybe he'll somehow manage to muddle through. Meanwhile, I'm waiting for pro-life voters to remember this guy named John McCain.