The next ‘unprovoked and dastardly' attack against American territory, on September 11, 2001, was naturally compared to Pearl Harbor. Yet in this case the facts did not speak so clearly.…The immediate cost in lives was higher, 3,021 (including 19 hijackers) as against 2,382 in 1941. To appreciate the impact, however, note that early estimates suggested that some 10,000 might have died as the two towers collapsed into dust and rubble. Moreover, the enemy had struck from within the United States, and a link with foreign organizations or states could only be assumed. There was no evident sequence of events with which the attack might be linked: no crisis, no failing negotiations, no ultimatums, no warnings.When the president spoke to Congress about the attacks on September 20, he realized that he needed to address a number of question that "Americans are asking". The first was: "Who attacked our country?"