DEFCON is the "defense readiness condition," which is state of alertness to military conflict as determined from time to time by the U.S. Armed Forces.

There are five levels; the lower the number, the higher the state of alertness:

DEFCON

There is no worldwide or country-specific DEFCON status: it can and has been declared to include only specific geographical areas. Worldwide the level has never been declared above DEFCON 3.

DEFCON 1 has never been declared in United States history.

DEFCON 3 has been declared only three times: after the Yom Kippur War, in South Korea in 1976 after an axe murder in the Korean DMZ, and after the September 11 attacks. DEFCON 2 has been declared only twice: during the Cuban Missile Crisis and the opening phase of the Persian Gulf War.

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