That time we almost killed everybody in 1983:
The 1983 exercise incorporated a new, unique format of coded communication, radio silences, participation by heads of government, and a simulated DEFCON 1 nuclear alert.
The realistic nature of the 1983 exercise, coupled with deteriorating relations between the United States and the Soviet Union and the anticipated arrival of strategic Pershing II nuclear missiles in Europe, led some members of the Soviet Politburo and Soviet military to believe that Able Archer 83 was a ruse of war, obscuring preparations for a genuine nuclear first strike.
In response, the Soviets readied their nuclear forces and placed air units in East Germany and Poland on alert. This relatively obscure incident is considered by many historians to be the closest the world has come to nuclear war since the Cuban Missile Crisis of 1962. The threat of nuclear war abruptly ended with the conclusion of the Able Archer 83 exercise on November 11.
In a nutshell:
- The US deployed missiles in Western Europe which could hit targets in approximately 6 minutes.
- The USSR determined they couldn’t respond in less than 6 minutes and the only way to avoid obliteration was to detect signals that a western decision to strike had been made prior to launch, then reacting with a preemptive strike.
- The USSR deployed intelligence sources to watch western figures (religious, political, and industrial) for any hint that they were preparing for nuclear war.
- The west kicked off Able Archer, a war game simulating imminent nuclear strike featuring militaries going to their highest level of alert and participation by senior leaders from the US and UK.
- The USSR figured this was the perfect cover to hid actual preparation and readied their missiles. (To what degree is debated)