The movie is the "Hollywood" edition of the 9/11 commision report, in case you have read it. Basically, the ball was dropped by many people, meaning more than one administration and by lots and lots of experts, our intelligence agencies as well as normal citizens for not being more vigilant. Let's not try to play politics by blaming one administration or another, the fact is that it happened, and just like many other things you learn from your mistakes, and hopefully you won't make the same mistake the next time.
I grew up in Germany where terrrorism was just a fact of life, you had groups such as Bader Meinhof and the RAF causing trouble every few years or so by bombing a disco or kidnapping some executives family, etc....yes it isn't the same scale as the WTC, however, the intended goal was the same.
I would encourage you to read the commission report as most likely a lot of facts are going to be left out in the movie. I am looking forward to the movie, as quite frankly the reading of the book was pretty dry at times, but very worthwhile.
Unfortunately, terrorism is something that is going to stay, if it doesn't come from AlQuida, it will come from some other source, even a domestic version, look at the OKC bombing. We just have to be more vigilant about our lives, but can't let the terrorist control it by us living in fear.
Sorry for the rant.
Derek