On October 6, 1973, Egypt and Syria launched a joint attack on Israel resulting in the Yom Kippur War. SAC remained at DEFCON 2 until November 15. On October 24, Strategic Air Command (SAC) was ordered to DEFCON 2, while the rest of the U.S. Armed Forces (with the exception of United States Army Europe (USAREUR)) were ordered to DEFCON 3. Instances of DEFCON 2 or 3 DEFCON 2 Cuban Missile Crisis ĭuring the Cuban Missile Crisis on October 16–28, 1962, the U.S. The initial DEFCON system had 'Alpha' and 'Bravo' conditions (under DEFCON 3) and Charlie/Delta under DEFCON 4, plus an 'Emergency' level higher than DEFCON 1 with two conditions: 'Defense Emergency' and the highest, 'Air Defense Emergency' ('Hot Box' and 'Big Noise' for exercises). had signed an agreement on increasing the operational readiness of NORAD forces during periods of international tension.' After the agreement became effective on October 2, 1959, the JCS defined a system with DEFCONs in November 1959 for the military commands. In October 1959, the JCS Chairman informed NORAD 'that Canada and the U.S. Increased intelligence watch and strengthened security measuresĪfter NORAD was created, the command used different readiness levels (Normal, Increased, Maximum) subdivided into eight conditions, e.g., the 'Maximum Readiness' level had two conditions 'Air Defense Readiness' and 'Air Defense Emergency'. Increase in force readiness above that required for normal readinessĪir Force ready to mobilize in 15 minutes Nuclear war is imminent or has already begunĪrmed forces ready to deploy and engage in less than six hours On January 12, 1966, NORAD 'proposed the adoption of the readiness conditions of the JCS system', and information about the levels was declassified in 2006: Readiness condition This is to preclude the possibility of confusing exercise commands with actual operational commands. Department of Homeland Security.ĭefense readiness conditions vary between many commands and have changed over time, and the United States Department of Defense uses exercise terms when referring to the DEFCON levels during exercises. military, such as Force Protection Conditions (FPCONS), Readiness Conditions (REDCONS), Information Operations Condition (INFOCON) and its future replacement Cyber Operations Condition (CYBERCON), and Watch Conditions (WATCHCONS), or the former Homeland Security Advisory System used by the U.S. Strategic Air Command (SAC).ĭEFCONs should not be confused with similar systems used by the U.S. The DEFCON 2 levels in the 1962 Cuban Missile Crisis and 1991 Gulf War applied only to the U.S. DEFCON level has never been more severe than DEFCON 3. According to Air & Space/Smithsonian, as of 2022, the U.S. Space Force) and different bases or command groups can be activated at different defense conditions. Secretary of Defense through the Chairman of the Joint Chiefs of Staff and the Combatant Commanders each level defines specific security, activation and response scenarios for the personnel in question.ĭifferent branches of the U.S. The DEFCON level is controlled primarily by the U.S. ĭEFCONs are a subsystem of a series of Alert Conditions, or LERTCONs, which also include Emergency Conditions (EMERGCONs). It increases in severity from DEFCON 5 (least severe) to DEFCON 1 (most severe) to match varying military situations, with DEFCON 1 signalling the outbreak of nuclear warfare. It prescribes five graduated levels of readiness (or states of alert) for the U.S. The DEFCON system was developed by the Joint Chiefs of Staff (JCS) and unified and specified combatant commands. The defense readiness condition ( DEFCON) is an alert state used by the United States Armed Forces. For other uses, see Defcon (disambiguation).

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