I’m not convinced that it’s ambition that has degraded his political character. I mostly fault the current incarnation of the Religious Right Wing Republican Party, who has taken such a stranglehold on the party and the process, that no one who didn’t purport to uphold their policies has a chance in hell of being elected.
I think John McCain (has come to) love this country so much that he truly wants to be at the helm so that he can make it the place he thinks would be better, same as Barack Obama. Sure, some ambition is requisite, but I don’t think ambition alone is poisonous.
But he simply can’t run as the same John McCain of 2000. That guy didn’t win the nomination then, and he won’t win the Presidency now. Unfortunately, I think down deep that’s who he really is, but having to mold himself to this other guy is so difficult that it causes him to constantly contradict himself.
Now, no matter how you look at it, I think that’s still a bad thing for this country. But I don’t ascribe nefarious motives to him based on ambition.