Well, we know whence he got his temper and candor:

Steve Scully: This is a political question in terms of how he gets the nomination, but just from what you have seen, how much support do you think he has among the base of the Republican Party?

Roberta McCain: I don't think he has any. I don't know what the base of the Repub--maybe I don't know enough about it, but I've not seen any help whatsoever.

Scully:  So can he then go on and become the nominee of this party?

McCain: Yes, I think holding their nose they're going to have to take him.

Scully:  Can you explain?

McCain:  Well, everything they've done and said.  ... Now I'm really popping off, but he worked like a dog to get Bush re-elected.  ...He's backed Bush in everything except Rumsfeld.  Have you heard other senators and congressmen backing Bush over eight years? Find me it--give me a name.  I've not seen any public recognition of the work that he's done for the Republican party.