You'd think Miller would have been used effectively by the Republicans in the South. He could campaign for Perdue, Corker and Allen and could probably sway a few conservative Democrats.
Allen maybe, but Miller was close to Barnes and probably wouldnt dream of backing Perdue... as with Corker, I'm not sure, Ford stikes me as one of the few Democrats of whom Miller would be very supportive of.
So i get the sense that Miller is only backing Santorum becuase he's a friend of his, indeed Ford and Santorum are meant to get along quite well... as nutty as Santorum is he does seem to be somone who's friends are very loyal and attached to, regardless of his poltics... and that's one reason why Miller is, so far, only openly supporting him rather than doing as he did back in '04.