Here's my tough assessment of the intelligence failure that appeared on September 12, 2001, "Mistakes Made the Catastrophe Possible":
The tactical blame falls on the U.S. government, which has grievously failed in its topmost duty to protect American citizens from harm. Specialists on terrorism have been aware for years of this dereliction of duty; now the whole world knows it. Despite a steady beat of major, organized terrorist incidents over 18 years (since the car bombing of the U.S. embassy in Beirut in 1983), Washington has not taken the issue seriously. … American officials have consistently held the view that terrorism is a form of criminal activity. Consequently, they have made their goal the arrest and trying of perpetrators who carry out violent acts. That's all fine and good as far as it goes, but it does not go far enough. This legalistic mindset allows the funders, planners, organizers, and commanders of terrorism to continue their work untouched, ready to carry out more attacks. The better approach is to see terrorism as a form of warfare and to target not just those foot soldiers who actually carry out the violence but the organizations and governments who stand behind them. … Many indications point to the development of a large Islamist terror network within the United States, one visible to anyone who cared to see it. … The information was out there but law enforcement and politicians did not want to see it.
The Congressional report released today (the Joint Inquiry into Intelligence Community Activities before and after the Terrorist Attacks of September 11, 2001) agrees with me, though with softer phrasing:
for a variety of reasons, the Intelligence Community failed to capitalize on both the individual and collective significance of available information that appears relevant to the events of September 11. As a result, the Community missed opportunities to disrupt the September 11th plot by denying entry to or detaining would-be hijackers; to at least try to unravel the plot through surveillance and other investigative work within the United States; and, finally, to generate a heightened state of alert and thus harden the homeland against attack. No one will ever know what might have happened had more connections been drawn between these disparate pieces of information. We will never definitively know to what extent the Community would have been able and willing to exploit fully all the opportunities that may have emerged. The important point is that the Intelligence Community, for a variety of reasons, did not bring together and fully appreciate a range of information that could have greatly enhanced its chances of uncovering and preventing Usama Bin Ladin's plan to attack these United States on September 11, 2001. (July 24, 2003)
