I've been reading this essay: The Bush 9/11 Scandal for Dummies, by Bernard Weiner, on the always useful Common Dreams web site. While I don't subscribe to the full conspiracy theory aspect of this, I think there are some things worth considering.
My take on this is that the Bush administration knew that something was likely to happen, and decided to take a calculated risk that it wouldn't be too bad. Their other alternative was to panic the U.S. and possibly bring our already shaky economy into a deep recession. Perhaps they feared that if they had warned us and nothing happened, they would have been roundly criticized for "crying wolf".
The problematic aspect of this: Apparently administration officials thought the risk was high enough that they changed their behavior over the summer to avoid the risk to themselves of commercial airline-based terrorism:
- Ashcroft stopped using commercial flights in July
- Bush, despite criticism over the amount of time he had spent on vacation (42% of his presidency), spent all of August in Crawford, Texas
- Newsweek reported that on September 10, "a group of top Pentagon officials suddenly canceled travel plans for the next morning, apparently because of security concerns"
- San Francisco Mayor Willie Brown was warned by "an airport security man" on September 10 to rethink his flight to New York for the next day
- Many members of a Bronx mosque were warned to stay out of lower Manhattan on September 11