I think The New York Times' writeup of the big GOP debate sort of misses the real lead. On the recommendation of my roommates who caught it live, I checked out the relevant section. Ron Paul made a kind of "blowback" argument that America's aggressive global military posture is part of the problem of global terrorism, rather than part of the solution. Then:
“May I comment on that?” Mr. Giuliani said, looking grim. “That’s really an extraordinary statement. That’s an extraordinary statement, as someone who lived through the attack of Sept. 11, that we invited the attack because we were attacking Iraq. I don’t think I’ve heard that before, and I’ve heard some pretty absurd explanations for Sept. 11.”
Mr. Giuliani was interrupted by cheers and applause. “And I would ask the congressman to withdraw that comment and tell us that he didn’t really mean that,” he said.
Giuliani didn't just look "grim," he looked genuinely outraged. And it was more like he was interrupted by wild cheers and thunderous applause. I still think I'm right and the cultural issues and so forth will doom Giuliani, but if you want the best case that I'm wrong you need to watch this clip. Sort of like Zell Miller's 2004 Convention speech it tapped directly in to the irrationalist brand of nationalism that increasingly motivates the contemporary GOP base.