DEFCON

The DEFense readiness CONdition (DEFCON) is an alert state used by the United States Armed Forces.

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. (As of April 2017, we are at DEFCON 4).

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

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, and each DEFCON level defines specific security, activation and response scenarios for the troops 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 risen higher than DEFCON 3. The DEFCON 2 levels in the 1962 Cuban Missile Crisis and 1991 Gulf War were not worldwide.

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