He will not make it "official" as it will tarnish (what is left to tarnish on this traitor?) his "military hero reputation" if he pulls a Jeffords and swiches parties. What will happen is Hillary will ask him to be her running mate and he will accept. He wants it to look like he is needed to save the nation and being drafted by Hillary would look more "honorable" (please pass the puke bag) than pulling a Jeffords.
Being that he will be 72 in 2008, and realizing that if Hitlery wins, he will be 80 in 2016, he knows his only chance is VP. He will never be President but will accept VP.
I can see that happening, even if it makes me puke.