If the right wing bickers constantly, Romney probably ends up with the nomination by default. Romney* is the hardest candidate for Obama to beat, because he can credibly play to the middle much more then the rest.

The rest are some combination of egomaniac, nut-job and religious fanatic. They just vary a bit in how each is weighted. They all have appeal only to the hard right. They all lose to Obama in a general election.

Jay

* With the possible exception of Huntsman. Huntsman looks like a sensible candidate but I don't know enough to be sure. It could be an illusion caused by lack of information and the relative insanity of the rest. He doesn't have chance though, so he doesn't matter.