Lieberman trashed every moral position he had which contradicted Liberal dogma. So will Nunn if this comes to pass.
Lieberman and John Glenn will go down in the dust bin of history where they belong, in the trash. They sold their souls for their political gain.
I've never gotten the sense that Lieberman cared about his few conservative positions as much as Nunn identified with his southern conservative Democrat image. Lieberman was named because he could solidify Jewish support and win over people with his "morality" that had little bearing on his actual political profile.
The degree of renunciation required of Nunn would negate all of his value to the ticket as a southern pro-defense conservative. I'd be surprised that Kerry would try something this dumb, except that he already did it with McCain.