"I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones."
"The only winning move is not to play"
"M.A.D. Mutually Assured Destruction. A perfect acronym if ever there was one."
— Dr. Conrad Zimsky, The Core
Mexican Standoff meets Lensman Arms Race meets Weapon Of Mass Destruction. Mutually Assured Destruction (MAD) was the doctrine that nuclear weapons, if deployed against another nuclear power, should be deployed en masse with the objective of completely destroying the other country's capacity to retaliate, and vice versa. In other words, if either the USA or the USSR ever used nuclear weapons against the other, it would be assured that neither the USA nor the USSR would exist anymore. Naturally this assumes both countries have a large enough stockpile to accomplish this - and they did. It also assumes that neither side has so much more firepower than the other that it could "win" a nuclear war with one sudden, overwhelming strike. The goal of a MAD strategy is counter-intuitive: it is actually to prevent a nuclear war. The theory goes that if each side knows that there is no way it can survive a nuclear war, it will get too scared to start one. Unless one or more of the superpowers decides a Taking You with Me or is ruled by an Omnicidal Maniac. Needless to say, this theory made people on all sides of the Cold War very nervous. Indeed, before the the end of the cold war, most academics thought the acronym "MAD" was appropriate - the strategy seemed insane*. It may come up in hypothetical World War III scenarios or works set in the late-era (1980s) of the Cold War. With the fall of the Soviet Union, MAD has lost its value as the focus shifts to combating terrorists who do not have access to a large stockpile of nuclear weapons. One of the theories for why the Cold War ended as peacefully as it did is that belief in this doctrine prevented the US and USSR from fighting any war directly against each other, for fear it would escalate to nuclear weapons and destroy both powers. Instead, it became a war of ideologies and economics, and according to the victors, the US eventually out-converted and out-spent the Soviets, who then collapsed under the weight of their own system*. Where there is no parity between the two nuclear belligerents, The Moscow Criterion is used. This was developed by the British, who could not build and fire the same number of rockets as the Sovs and who did not trust the Americans to launch their own missiles to back up a MAD doctrine - instead, the aim is to have the ability to slaughter as many of the enemy civilians as possible, thus attaching a prohibitively high human cost to a nuclear release by the more heavily-armed power.