For Nearly Two Decades the Nuclear Launch Code at all Minuteman Silos in the United States Was 00000000: Those in the U.S. that had been fitted with the devices, such as ones in the Minuteman Silos, were installed under the close scrutiny of Robert McNamara, JFK’s Secretary of Defence. However, The Strategic Air Command greatly resented McNamara’s presence and almost as soon as he left, the code to launch the missile’s, all 50 of them, was set to 00000000.
Oh, and in case you actually did forget the code, it was handily written down on a checklist handed out to the soldiers. As Dr. Bruce G. Blair, who was once a Minuteman launch officer, stated:
Our launch checklist in fact instructed us, the firing crew, to double-check the locking panel in our underground launch bunker to ensure that no digits other than zero had been inadvertently dialed into the panel.
This ensured that there was no need to wait for Presidential confirmation that would have just wasted valuable Russian nuking time. To be fair, there was also the possibility that command centers or communication lines could be wiped out, so having a bunch of nuclear missiles sitting around un-launchable because nobody had the code was seen as a greater risk by the military brass than a few soldiers simply deciding to launch the missiles without proper authorization.