He's like Britney Spears.
You know it's going to happen. He's just going to piss off too many people with his ego, or otherwise self-destruct. And for many Republicans, the whole Giuliani appeal is that he could win -- once he starts to look vulnerable, his support will plummet because even his supporters don't love him. And he's a candidate running from his strength on national security when he's never actually done anything for national security. Surely somebody will notice.
Finally, he's said so many times, "Thank God George Bush is our president," it's hard for me to see how that can help him?
Anyway, what will be Giuliani's downfall? Public spat with ex-wife? Ranting tirade at Romney? New policy to ban pizza deliveries? Shaves head? Marries Kevin Federline?
Points for creativity...