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DEFCON levels

The defense readiness condition (DEFCON) is an alert state used by the United States Armed Forces.[1]

The DEFCON system was developed by the Joint Chiefs of Staff (JCS) and unified and specified combatant commands.[2] 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.[1]

DEFCONs are a subsystem of a series of Alert Conditions, or LERTCONs, which also include Emergency Conditions (EMERGCONs).[3]


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 DEFCON 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) 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),[4] 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,[2] and the United States Department of Defense uses exercise terms when referring to the DEFCON levels.[5] This is to preclude the possibility of confusing exercise commands with actual operational commands.[5] 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:[6]

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 6 hours
DEFCON 3 ROUND CALLISTO 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".[6] 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."[6] After the agreement became effective on October 2, 1959,[6] the JCS defined a system with DEFCONs in November 1959 for the military commands.[2] 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).[6]


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.[7]

Persian Gulf War

On January 15, 1991, the Joint Chiefs of Staff declared DEFCON 2 in the opening phase of Operation Desert Storm during the Persian Gulf War.[8]


Yom Kippur War

On October 6, 1973, Egypt and Syria launched a joint attack on Israel resulting in the Yom Kippur War. The U.S. became concerned that the Soviet Union might intervene, and on October 25, U.S. 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 Central Intelligence Agency reports indicating that the Soviet Union had sent a ship to Egypt carrying nuclear weapons along with two other amphibious vessels.[9] 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.[10]

Operation Paul Bunyan

Following the axe murder incident at Panmunjom on August 18, 1976, readiness levels for U.S. forces in South Korea were increased to DEFCON 3, where they remained throughout Operation Paul Bunyan.[11]

September 11 attacks

During the attacks of September 11, 2001, the U.S. Secretary of Defense Donald Rumsfeld ordered to increase the DEFCON level to 3, and also a stand-by for a possible increase to DEFCON 2. It was lowered to DEFCON 4 on September 14.[12]

In media

  • DEFCON was featured prominently in the films Armageddon, Def-Con 4, WarGames, Hunter Killer, Thirteen Days, Watchmen, Independence Day, The Sum of All Fears, By Dawn's Early Light, Crimson Tide, X-Men: Days of Future Past, Fail Safe, and Canadian Bacon.
  • The television series Deutschland 83 depicts the events which occurred in 1983 when the level was raised to a simulated DEFCON 1 during NATO exercise Able Archer 83. In the story line, briefing papers released under the Freedom of Information Act reveal that Operation Able Archer, a major war games exercise conducted in November 1983 by the US and its NATO allies, was so realistic it made the Soviets believe that a nuclear strike on its territory was a real possibility.[13]
  • It is featured in the television series La Casa de Papel (T4).
  • It is featured in the 2006 real-time strategy video game DEFCON.
  • DEFCON is a key element in Twilight Struggle, a board game about the Cold War.
  • In the video game Unturned, the DEFCON system appears to have been adopted worldwide; the level is raised to a DEFCON 1 after the start of a zombie infection.
  • In the video game No One Lives Forever 2: A Spy in H.A.R.M.'s Way, NATO forces are brought to DEFCON 2 status in the final chapter as H.A.R.M. begins its invasion of Khios.
  • Surf punk band Man or Astro-man? released an album in 2013 titled Defcon 5...4...3...2...1 featuring songs titled after every level of the DEFCON system.
  • British indie band Pop Will Eat Itself (PWEI) released a song titled "Def. Con. One".
  • In The Santa Clause 2, starring Tim Allen, the North Pole's defense system is revealed to be based on levels of ELFCON, a reference to the United States' DEFCON.
  • The DEFCON system is parodied in the 2015 animated film Inside Out, which is utilized by the emotions of Riley Andersen's father during a conflict at dinner.
  • MS-DEFCON is the Microsoft Patch Defense Condition Level created by Computer columnist Woody Leonard. This DEFCON-style alert system notifies computer systems administrators when to safely apply updates to Windows-based servers.[14]
  • In the 2018 video game Fallout 76, a semi-permanent state of DEFCON 1 exists, which allows the players access to the automated nuclear missile silos.
  • In the television shows Designated Survivor and Designated Survivor: 60 Days, DEFCON is used when the capital is attacked to classify the severity of the state of emergency.
  • In the video game Call of Duty: Black Ops (specifically in the Zombies storyline), a semi-permanent state of DEFCON 1 exists, and can be lowered to level 5 by flipping switches on the map also named "Five", a loose depiction of the Pentagon. Lowering the DEFCON level to 5 lets the player teleport into the Pack-a-Punch room. After a short time, the DEFCON level will eventually raise itself back up to 1, opening the doors of said room.

See also


  1. ^ a b "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)
  2. ^ a b c Sagan, Scott D. (Summer 1985). "Nuclear Alerts and Crisis Management" (pdf). International Security. 9 (4): 99–139. doi:10.2307/2538543 – via Project Muse.
  3. ^ "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.
  4. ^ "Chairman of the Joint Chiefs of Staff Instruction 6510.01F".
  5. ^ a b "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.
  6. ^ a b c d e NORAD/CONAD Historical Summary: July -December 1959 (PDF) (Report). Retrieved 2013-09-25.
  7. ^ "DEFCON DEFense CONdition".
  8. ^ 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.
  9. ^ Naftali, Tim. "CIA reveals its secret briefings to Presidents Nixon and Ford". CNN. Retrieved 26 August 2016.
  10. ^ 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.
  11. ^ 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 |journal= (help)
  12. ^ "Complete 911 Timeline: Donald Rumsfeld's Actions on 9/11". Retrieved 2016-08-02.
  13. ^ Doward, Jamie (November 2, 2013). "How a NATO War Game Took the World to Brink of Nuclear Disaster". The Observer. London. Retrieved September 23, 2016.
  14. ^ "MS-DEFCON System @ AskWoody".

External links

  • Media related to DEFCON at Wikimedia Commons
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