Re: Only if you assume WW III would be US vs Russia
This, a hundred times this.
Imagine you are the electrician tasked with wiring up the nuclear button on Donald Trump's desk. Nobody is ever going to be able to test it properly, so you simply leave one wire unconnected (or, if it is a push-to-break switch, screw both wires into the same terminal). If the other side fire first, you're dead anyway; but if the USA fires first, and the bombs don't go off, you are now officially the person who prevented nuclear annihilation -- and that's got to be something you can dine out on for a long time. Even if the probability is really minuscule compared to the already tiny probability of your deliberate error being found out, the payoff of being the hero(ine)? who saved the world is worth the risk of a short punishment detail.
Now consider just how many other people there are, who are similarly in a position to sabotage the nukes, and with similar ideas about saving humanity (or even just never having to cook again) being worth a bollocking ..... Only one of whom has to fail to do their job properly, for the launch to go spectacularly Tango Uniform. And then multiply that by every country with nuclear capabilities. I almost feel sorry for anyone trying to launch the nuclear missiles. But only almost, because they did try to kill me, and everybody else.
I just think there is too much interest in preventing a nuclear missile launch, among those actually on the front line and with the actual power of make-or-break, for it ever actually to happen.