Sorry to do this, but I read this CNN news story and I'd like to point out the technology existed. The procedures and policies may have been lacking. http://www.cnn.com/2001/US/09/16/inv.hijack.warning/ Military officials at NORAD ordered fighter jets from Langley Air Force Base in Virginia to intercept the flight, but neither the FAA, NORAD, nor any other federal government organization made any effort to evacuate the buildings in Washington. Officials at the Pentagon said that no mechanism existed within the U.S. government to notify various departments and agencies under such circumstances. Actually, there has been a mechanism to alert almost every public safety point in the nation for many years. Quoting from the NAWAS manual:
The National Warning System (NAWAS) is a 24-hour continuous private line telephone system used to convey warnings to Federal, State and local governments, as well as the military and civilian population. Originally, the primary mission of the NAWAS was to warn of an imminent enemy attack or an actual accidental missile launch upon the United States. NAWAS still supports this mission but the emphasis is on natural and technological disasters.
In todays post-Cold War environment, the threats imposed by disasters make it imperative for all government officials to have access to an effective and reliable means of warning the public of impending emergencies so that they may take protective actions. Title VI of the Robert T. Stafford Disaster Relief and Emergency Assistance Act authorizes the use of the NAWAS to support the All-Hazards emergency response mission of the Federal Emergency Management Agency (FEMA). NAWAS is used to disseminate warning information concerning natural and technological disasters to various warning points throughout the continental United States, Alaska, Hawaii and the Virgin Islands. This information includes but is not limited to acts of terrorism including Weapons of Mass Destruction (WMD) after aircraft incidents/accidents, earthquakes, floods, hurricanes, nuclear incidents/accidents, severe thunderstorms, tornadoes, tsunamis and winter storms/blizzards. NAWAS allows issuance of warnings to all stations nationwide or to selected stations as dictated by the situation.
The rumor is it takes NORAD less than 3 minutes to issue an alert. The government had the means to issue a warning.