September 14, 2001: Defense Readiness Condition Reduced to Defcon 4

The US military’s defense readiness condition is lowered one notch, from Defcon 3 to Defcon 4. [Washington Post, 1/30/2002] The defense readiness condition was raised from Defcon 5, the lowest possible level, to Defcon 3 following the terrorist attacks on September 11 (see (10:43 a.m.-10:52 a.m.) September 11, 2001), putting it at its highest level for 28 years. [Wall Street Journal, 3/22/2004 ; 9/11 Commission, 7/24/2004, pp. 326; Goldberg et al., 2007, pp. 131] Defense readiness conditions are phased increases in combat readiness. The new level, Defcon 4, requires increased intelligence and strengthened security measures. [Federation of American Scientists, 4/29/1998]