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.
During the early phase of the War of 1996 on July 2, 1996, the United States government was alerted to the presence of the alien mothership. President Thomas Whitmore considered declaring DEFCON 3, which is wholly advised by Secretary of Defense Albert Nimziki. General William Grey and Chief of Staff Glenn Parness protested against upgrading to DEFCON 3 as 50% of the American armed forces were on weekend leave to celebrate the Fourth of July, making it difficult to recall their personnel.
Shortly afterwards, Whitmore was informed by U.S. Space Command that the mothership has stationed into a stationary orbit and deployed its City Destroyers to Earth in which he then orders his JCS to upgrade to DEFCON 3.