I maintain that the ominous quote from LeMay notwithstanding, the General and all SAC commanders who followed him were bound to their oath, would never condone or encourage the unauthorized release of nuclear weapons without presidential approval, unless it was clearly demonstrated beyond doubt that the presidential line of authority no longer existed, in which case pre-planning would carry the day.
The fact is, SAC's psychological screening program obviously did the job because nobody in our armed forces has ever gone berserk or tried to fire a nuke on their own without authorization.
Dr Strangelove, like "Fail-Safe", was fiction and may have borrowed from factual instances and data, but the nuclear disasters they portrayed were never even close to actually occurring, except in the minds of the anti-nuclear crowd who believed in unilateral disarmament.
One of the things I find funny is that the Soviets are never portrayed as having problems with failsafes, etc. They lost a bunch of subs, had a mutiny on a destroyer (that almost made it to safety!), shot down innocent airliners (that they KNEW were airliners!), irradiated parts of the Ukraine, apparently have misplaced some nukes, and generally effed up on a regular basis - but noooooo!, they would never have a problem with their military. Not the Worker's Paradise - they'd never screw up like we would.