How close America has come to nuclear disaster (21 sep 13)
http://www.theguardian.com/world/2013/sep/20/usaf-atomic-bomb-north-carolina-1961
Also, it was only the insubordination of a Russian submarine commander during the Cuban missile crisis which prevented a nuclear war:
http://en.wikipedia.org/wiki/Vasili_Arkhipov
This all happened under Saint John F Kennedy.
The world also came close to nuclear war in 1983:
http://www.theguardian.com/uk-news/2013/nov/02/nato-war-game-nuclear-disaster