My not-much-fuel argument serves only to play into the miniaturization and quickness of response arguments. So, Missile Command 1980, but with the turret at the top of the screen (in spaceeeeee), pointed downwards, and the ICBMs traveling by horizontally, in the upper exosphere, but your intercept missiles are hella faster. Surely one could build a killswitch such that once a nuclear bomb system is armed, Uranium cores are forced together via a powerful spring or something upon the loss of electricity and thus initiate the chain reaction, at altitude or otherwise. Looking forward to seeing the FBI tomorrow, at this point, thanks. There is also at least some value to a quasi-secret defense system, in which, say, only the Ruskies know about it, but maybe we know they know, and they can't divulge too much publicly without revealing something fairly compromising. Ugh, who knows. I kinda hate intelligence agency games. You very quickly have to get into the error bars / uncertainty.