Cain is as close as I can come to supporting someone on principles. Santorum and Bachman, perhaps, but they seem to have no chance. Other than that, it is simply a bunch of RINOs jockeying for position.
The Romney folks won't change. The rest of us will go with whichever conservative seems to have the best chance of taking the nomination away from him. Doesn't have to be any particular conservative, just has to be a conservative.