Truth is, the only thing that anyone might've reasonably been able to do that could've stopped 9/11 would have been to secure the cockpit doors. Given that we have had hijackings in the past, I don't understand why it wasn't done years ago. I had never flown before 9/11, but I was surprised to learn it was so easy to get access to the cockpit. So, while you can blame Bush for not doing that, you can also blame all the previous presidents since Islamic hijackings became a thing in the '70s.