Why did the military require human beings to turn the keys if they expected people (and weeded out people unwilling) to turn the key blindly? A wire would have been much more efficient...
Humans are probably more difficult to hack (I hope) and more resistant to noise (I hope).
A weak ago, there was a discussion about the “Letters of last resort” https://news.ycombinator.com/item?id=7165048 (56 points, 6 days ago, 50 comments). They are secret instructions for nuclear submarine commanders in case of something killed the whole UK government.
From Wikipedia:
> According to Peter Hennessy's book The Secret State: Whitehall and the Cold War, 1945 to 1970, the process by which a Trident submarine commander would determine if the British government continues to function includes, amongst other checks, establishing whether BBC Radio 4 continues broadcasting.
This kind of safeguards is easier to implement in humans than in automatic systems. How do you distinguish from the submarine the lack of communication caused by a nuclear attack from a problem caused by a massive electricity outage and a big fire in the BBC building? Maybe you can listen to some Canada and Australia signals to hear if there is a problem.
It is not hard to hack a human, it happens every day - we know it by the term radicalization these days. There are people who abandoned comfortable Western lives to fight jihads and become suicide bombers. Another term for it is brainwashing. In the Cold War people became defectors. You can hack a human by speaking to them or by showing them some text to read, techniques thousands of years old.
It's not possible to know, for sure, if the orders are lawful or sane (since we are talking about MAD, chances are they aren't sane, although they may be legal). That's why humans were designed into the system - they have to judge and face the consequences of their judgement.
It's evident that the original purpose of placing "moral processors" in the loop was lost after the fact.
