and when you go beyond the evidence of that day -
PNAC) when you realize that in 2000, a group of future bush admin people wrote a paper in which they planned out the invasions in the middle east and said that "a catalyzing event - like a new Pearl harbor" would be needed to justify these invasions for the American people.
Warnings) 29 separate foreign intel warnings on 9/11 which Bush ignored:
http://www.cooperativeresearch.org/timeline.jsp?timeline=complete_911_timeline&warning_signs:_specific_cases=foreignIntelligenceInvestigation) JFK, Challenger, Columbia, pearl harbor - all investiations started within a week. Bush told congress there would be zero investigation and Rusy shipped all the metal (possibly containing explosives residue) to china for recycling in violation of federal law. (it did come 441 days later after mass protests, but was very limited)
Economy) After dot-com bust of jan 2001, the economy was sinking to another recession. monster war spending helped that recover and let the fed justify lowering rates which helped the economy recover.
Motive) Early 2002, the towers would have been demolished anyway due to cost prohibitive asbestos and corrosion repairs needed. Also money, the owner put $14 MILLION down and cashed checks for almost TEN BILLION dollars, six weeks later.
More motive) 2.3 trillion dollars announced missing on 9/10 from Pentagon accounting dept. The next morning, a plane hits the pentagon accounting department. The 2.3 trillion is never found. hell, the plane hits at 9:32 AM after what I am guessing is a 9:30 AM meeting.
So even if you believe everything made sense that morning (which I certainly don't, but even if you do), you'll see that Bush investigating himself for 9/11 is a very bad thing. more than enough motive and example to show the investigation was biased.