The horrific events of 11 September 2001, when four hijacked jetliners crashed into and collapsed the twin-towered World Trade Center in New York, slammed into the Pentagon, and nose-dived into a field in rural Pennsylvania (ostensibly on a mission to destroy the U.S. Capitol or the White House), have been indelibly etched into the nation's collective experience and memory as "9/11." These unprecedented terrorist-organized and -executed suicide attacks have had an immeasurably profound political, strategic, military, economic, and cultural impact upon the United States and much of the world. The legacy of the 2,986 fatalities on 9/11, as well as a seeming lack of preparedness, has transformed (at least in the short term) national security policy and world affairs.