On this point, I am admittedly doubtful about the reports regarding the towers collapsing. There are many many little red flags which have cropped up regarding the matter. I don't think we have been told the whole story, But I don't think the US instigated it. However, I see two other possibilities. 1. That the US Gov knew about the plan, and simply helped it long, AS being expedient to the long term aims of the administration, and 2. That it was either instigated, or helped along by Israel, (as has also been stringly suggested. (Note the fact (at least reported as such)that Isrealis were strangely absent when it happened.