JFK'S PAL

In 1962, President Kennedy instituted the "Permissive Action Link" ("PAL") system.  This was the procedure where, in order to launch a nuclear attack, the President had to recite an 8-digit number which would then be forwarded to and dialed in by the various missile launch technicians or the aircraft weapons officers immediately prior to the release of nuclear missiles and bombs.  If the code matched what had been previously programmed into the launch panel, then the nuclear devices would become armed and could be sent on their way.  The launch code was contained in a briefcase called "the football" which was (and still is) carried by a serviceman who accompanies the President wherever he goes.  Fans of Dr. Strangelove and Fail Safe are aware that the code is supposed to be changed daily.

However, as reported by the "Today I Found Out" website, from 1962 until 1977, the code was never changed with respect to all of the Minuteman silos in the United States and in fact remained "00000000" for over fifteen years. The military wanted the ability to fire the missiles as soon as possible if necessary and instructed the launch crews to always have the dials preset to the 8-zero combination.