Rather than the govt being actually involved in the 911 attacks, this is about the cover-up afterward when it seems the CIA not only knew that a couple of the terrorists were in the US, but actively worked to keep the FBI from knowing about it, then after 911 they worked diligently to continue denying the FBI access to any of the information.
Insiders voice doubts about CIA’s 9/11 story
Former FBI agents say the agency’s bin Laden unit misled them about two hijackers
http://www.salon.com/2011/10/14/insiders_voice_doubts_cia_911/
