How much better off would the US -- to say nothing of the rest of the world -- be, if we'd just shrugged off the 9/11 attacks as unique criminal acts by deranged cultists, rather than a military event that called for multi-trillion-dollar wars?
Impossible to say, really, one may as well ponder the state of the world if Christianity hadn't come about as well. But if I had to guess, the US wouldn't be in so much debt and they wouldn't be as hated in some countries. Saddam would still be killing his own people and the Taliban would still be hanging people from goalposts in soccer stadiums. On and on it goes, and I see no relevance in speculating about it. Any 9-11 discussion, especially here on slashdot, tends to get out of hand no matter what your viewpoint, so I tend to avoid them. My point was that it is normal for attitudes to change in response to tragic events.