DEFCON level 1, the maximum alert, has never been reached
It has only been declared twice, in the Cuban Missile Crisis and in the initial phase of Operation Desert Storm during the Gulf War.
DEFCON (acronym for Defense Condition, Defense Condition, in Spanish) is a term used by the United States to measure the level of readiness and defense of its Armed Forces. These defense conditions describe progressive states of alertness and readiness. DEFCON levels are adjusted based on the severity of the military situation. The Joint Chiefs of Staff and the commanders of the armed forces are in charge of increasing the alert level from 5 to 4, 3, 2 and 1. Right now the United States would be at level 4, according to the press in that country, since it is not official information. Different branches of the military (Army, Navy, or Air Force) and different bases or contingents may have different DEFCONs.
Situation in times of peace.
Situation in which the activity of the intelligence services is slightly increased and the National Security measures are tightened. During most of the Cold War or the Crimean Crisis of 2014, this level was maintained.
It implies an increase in the availability of forces above normal. Military radio calls used by the Armed Forces go into security mode. The air force ready to deploy in 15 minutes This level was reached in 1962 during the Cuban Missile Crisis, following the discovery by the United States of medium-range nuclear missile bases of Soviet origin on the Cuban island. Later, during the Yom Kippur War in 1973, when the Soviet Union threatened to intervene on Egypt’s behalf, the entire US military moved to this level. The last time this level was reached was during the September 11, 2001 Islamist attacks on the World Trade Center in New York.
It is the preliminary step for a nuclear war. The armed forces are ready to deploy and fight in less than 6 hours It has only been declared twice, in the Cuban Missile Crisis and in the initial phase of Operation Desert Storm during the Gulf War, between 1990- 1991.
It is the highest alert level. It has never been used. This level would only be activated in the event of an imminent attack on the US military or its territory by a large foreign military force. At this level, the use of weapons of mass destruction is authorized.