There is practically no dissention in the GOP. Just a few old guys that were far-leftist Republicans back in the day... or are still leftist (Chafee).
Democrats, on the other hand...
Umm ... Zell Miller. That's it. And let's be honest about Zell, he's crazy.
I had a thread a long time ago about Democrats who are supporting Bush. It's lost somewhere in this mess of forums. If you want to go hunt for it, feel free. I think it had 5 current politicians who are backing Bush (Miller being on), and other former politicians who are backing Bush.