I didnt understand this for a long time and I've never understood the idea that someone would govern as a roman catholic first and whatever second. I always believed, from I was no age, that politicians governed on the basis of their mandate, usually whatever they'd promised before the election. I never saw religion coming into it.
My understanding of Roman Catholicism has always been the same as Benedict has clarified lately, that the church is about forming conscience and not interfering with politics. A hell of alot of the violence here, which seems at some level to have linked with things like the CIA fact book, has been excused or rationalised on the basis that something called "political catholicism" existed, that there was a kind of conspiratorial nature to catholics who all take orders from a foreign power.
To me that's bullshit and I dont understand how anyone ever believed it, no one worries that a president who is a southern baptist or methodist or presbytarian would govern as decided by the authorities of any of those churches.
I dont think mormonism will come into it, for some fence sitting liberals maybe, a lot of people feel strongly enough about religion to never vote for anyone who has any religion. On the other hand like I said I think this is code, I think its about enticing the right wing fringe which never votes or refuses to into voting again. The US being polarised as it is both left and right fight for their "stay at home votes" as much as they do for any undecided.