And amazingly, Matthew Broderick had nothing to do with it.
WarGames, anyone? No? Anyway, according to recently declassified documents, 1983 almost saw the collapse of modern civilisation as we know it and the outbreak of World War III.
A NATO training exercise, codenamed Able Archer, had the Soviet Union utterly convinced that the Western superpowers were planning a nuclear launch. As written in a paper by the US President's Foreign Intelligence Advisory Board, the situation "may have inadvertently placed our relations with the Soviet Union on a hair trigger.”
The report adds that "that Soviet military leaders may have been seriously concerned that the U.S. would use Able Archer 83 as a cover for launching a real attack," saying that some Soviet forces were prepared to use Able Archer as casus belli - a case for war. Look at us using fancy Latin.
According to later analysis, the Soviet Union was already apprehensive of Ronald Reagan's tactics and foreign policy stances, including its Star Wars missile defensive initiative and the fact that most of the high-ranking officials in the Soviet Union were gravely ill, meaning there would likely have been utter chaos and a lack of leadership had NATO attacked.
The National Security Archive, which requested the documents be declassified, said that "the war scare was real" in 1983, comparing it to the likes of the Cuban Missile Crisis in 1962.