I don't know what the other trajectory would have been, i.e. had 9/11 been foiled. But I do think it served as the ultimate excuse to curtail rights and freedoms. The long wars it led to both warped our society at home and led to two generations of militarization of kids. For instance, I remember how disgusted and shocked I was at the explosion of military displays at baseball and football games. This was all basically fascism using the attack on our free society to embed xenophobic militarism into every aspect of daily life.

It's speculative, yea. But without 9/11 I don't think we'd have a culture of giant military style pickup trucks rolling coal and waving flags (American or Confederate). I think the militia movement of the 90s would have stayed much more contained and minor without something to justify their claims of conspiracy and NWO takeover. And I think we wouldn't have developed the sense that we were all living in a disaster movie, and become so callous and inured to what we see on the news. I don't think I can or should summarize all this in a post, but maybe the best way to put it would be that it ended the American Century, and bent the arc of our civilization towards decay and self destruction. It exposed a crack in the foundation of the country that has grown, and keeps growing. I suppose that could have happened any number of ways.