I won't go so far as to vote for the Witch, but if McCainiac somehow did win the nomination, I'd go third party. Personally, I don't think that will happen after this week, when he jabbed a thumb in the eye of the entire GOP base. All he managed to accomplish was the torpedoing of his own and Bill Frist's Presidential candidacies. It goes without saying that nobody from either party will likely ever trust him again as megalomaniacs care only about looking out for themselves.
McCain will run third party -- just remember Ross Perot. That's what he is angling for. And maybe Hillary will offer him a VP spot.