The DEFCON system was developed by the Joint Chiefs of Staff (JCS) and unified and specified combatant commands. It prescribes five graduated levels of readiness (or states of alert) for the U.S. military. It increases in severity from DEFCON 5 (least severe) to DEFCON 1 (most severe) to match varying military situations.
The DEFCON level is controlled primarily by the U.S. president and the U.S. 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.
Different branches of the U.S. Armed Forces (i.e. U.S. Army, U.S. Navy, U.S. Air Force, U.S. Marine Corps, U.S. Coast Guard, U.S. Space Force) and different bases or command groups can be activated at different defense conditions. In general, there is no single DEFCON status for the world or country and it may be set to only include specific geographical areas. According to Air & Space/Smithsonian, as of 2014, the worldwide DEFCON level has never been more severe than DEFCON 3. The DEFCON 2 levels in the 1962 Cuban Missile Crisis and 1991 Gulf War were not worldwide.
DEFCONs should not be confused with similar systems used by the U.S. 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 United States Department of Homeland Security.
Defense 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. This is to preclude the possibility of confusing exercise commands with actual operational commands. 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||Exercise term||Description||Readiness|
|DEFCON 1||COCKED PISTOL||Nuclear war is imminent or has already started||Maximum readiness. Immediate response.|
|DEFCON 2||FAST PACE||Next step to nuclear war||Armed forces ready to deploy and engage in less than six hours|
|DEFCON 3||ROUND HOUSE||Increase in force readiness above that required for normal readiness||Air Force ready to mobilize in 15 minutes|
|DEFCON 4||DOUBLE TAKE||Increased intelligence watch and strengthened security measures||Above normal readiness|
|DEFCON 5||FADE OUT||Lowest state of readiness||Normal readiness|
After 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". In October 1959, the JCS Chairman informed NORAD "that Canada and the U.S. 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. 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).
Cuban Missile Crisis
During the Cuban Missile Crisis on October 16–28, 1962, the U.S. Armed Forces (with the exception of United States Army Europe (USAREUR)) were ordered to DEFCON 3. On October 24, Strategic Air Command (SAC) was ordered to DEFCON 2, while the rest of the U.S. Armed Forces remained at DEFCON 3. SAC remained at DEFCON 2 until November 15.
Persian Gulf War
Yom Kippur War
On October 6, 1973, Egypt and Syria launched a joint attack on Israel resulting in the Yom Kippur War. The United States became concerned that the Soviet Union might intervene, and on October 25, US forces, including Strategic Air Command, Continental Air Defense Command, European Command and the Sixth Fleet, were placed at DEFCON 3.
According to documents declassified in 2016, the move to DEFCON 3 was motivated by CIA reports indicating that the Soviet Union had sent a ship to Egypt carrying nuclear weapons along with two other amphibious vessels. Soviet troops never landed, although the ship supposedly transporting nuclear weapons did arrive in Egypt. Further details are unavailable and remain classified.
Over the following days, the various forces reverted to normal status with the Sixth Fleet standing down on November 17.
Operation Paul Bunyan
September 11 attacks
During the September 11 attacks, Secretary of Defense Donald Rumsfeld ordered the DEFCON level be increased to 3, and also a stand-by for a possible increase to DEFCON 2. It was lowered to DEFCON 4 on September 14.
- COGCON – Continuity of government readiness level
- Doomsday Clock
- HURCON – Hurricane Condition threat rating (military-developed scale)
- National Command Authority
- National Military Command Center
- National Terrorism Advisory System
- UK Threat Levels – Similar British system used for terrorism threats
- "Department of Defense Dictionary of Military and Associated Terms" (PDF). 12 April 2001 (As Amended Through 19 August 2009). Archived from the original (PDF) on 8 November 2009. Retrieved 1 February 2014.CS1 maint: others (link) (DEFCON is not mentioned in the 2010 and newer document)
- Sagan, Scott D. (Summer 1985). "Nuclear Alerts and Crisis Management" (pdf). International Security. 9 (4): 99–139. doi:10.2307/2538543 – via Project Muse.
- "Emergency Action Plan (SEAP)" (PDF). United States Army Corps of Engineers Savannah District (CESAS) Plan 500-1-12. 1 August 2001. Archived from the original (PDF) on 2013-02-03.
- "Chairman of the Joint Chiefs of Staff Instruction 6510.01F". jcs.mil.
- "Emergency Action Procedures of the Joint Chiefs of Staff, Volume I - General" (PDF). US DoD FOIA Reading Room. April 24, 1981. pp. 4–7. Archived from the original (PDF) on January 13, 2014.
- NORAD/CONAD Historical Summary: July -December 1959 (PDF) (Report). Retrieved 2013-09-25.
- "DEFCON DEFense CONdition". fas.org.
- Meyers, Harold P. (1992) "Nighthawks over Iraq, a study a study of the F117-A stealth fighter in operations Desert Shield and Desert Storm." U.S. Air Force Office of History.
- Naftali, Tim. "CIA reveals its secret briefings to Presidents Nixon and Ford". CNN. Retrieved 26 August 2016.
- Goldman, Jan (16 June 2011). Words of Intelligence: An Intelligence Professional's Lexicon for Domestic and Foreign Threats. Scarecrow Press. pp. 93–. ISBN 978-0-8108-7476-3.
- Probst, Reed R. (16 May 1977). "Negotiating With the North Koreans: The U.S. Experience at Panmunjom" (PDF). Carlisle Barracks, Pennsylvania: U.S. Army War College. Archived from the original (PDF) on October 24, 2005. Retrieved 17 December 2009. Cite journal requires
- "Complete 911 Timeline: Donald Rumsfeld's Actions on 9/11". www.historycommons.org. Retrieved 2016-08-02.
- Media related to DEFCON at Wikimedia Commons