Douthat expects it to be played:
The Obama White House may not make Mormonism an issue directly, but that doesn’t mean that the incumbent won’t benefit from the coverage that Romney’s religion will inevitably receive. And it’s possible that Romney would stand to gain if he spoke more directly and in more detail about a worldview that’s clearly at the heart of his identity, and that provides one of the most authentic and deeply-felt influences on his often inauthentic-seeming personality. In one form or another, there will be plenty of attempts to define Romney’s religion for him, and he might be better off doing his own defining first.
But he can't, because even talking about it will send chills up Christianists' spines. And yet questions will emerge: why were his in-laws barred from his Temple wedding service? Why was his dad born 
in Mexico? Could it be he was there because that's where many of the older hard-core polygamists sought refuge after being hounded by the US government?
Romney's grandparents were monogamous, but polygamy is a big feature of the family tree before that: one of Romney's great-grandfathers had five wives, and one of his great-great grandfathers – the "Apostle Paul of Mormonism" – had twelve wives (he was murdered by the former husband of one of them), thirty children, and 266 grandchildren.
Romney really is LDS monarchy, his family going back deep into the heart of the religion's history. I don't see how he manages to avoid talking about this, about whether Mormonism is, as Ross has called it, a "heresy", whether his view of God is as a human, whether humans can become gods, etc. The reason I think he has to find a way to address it is that it is such a profound influence on him that, unless people see a little of how his faith helped form his character and judgment, they will not be able to relate to him at all. For these reasons, I think the taboo on talking about the LDS could hurt more just as much as airing it all could. It's close to lose-lose unless he can manage a speech as great as Obama's on Wright.
I should add and underline that I don't regard any of this as faintly relevant to his capacity to be president. I think it is an amazing and very American thing for this race to be between a black man and a Mormon, given this country's history. It's an astounding achievement in both racial and religious progress. But then I'm not the one insisting that people's religious faith be placed firmly in the public square on the same level as secular argument – and that candidates be judged by that. That's the party Romney leads.
(Photo: Parley Pratt, major Mormon figure and great-great grandfather of Mitt Romney.)
The Dish 