During the Cold War, the US had been even more vulnerable, in technological terms, to a nuclear attack from Russia, but “mutual assured destruction” prevented the worst by keeping vulnerability more or less symmetrical. Russia controlled great force, but it could not acquire power over the US from its arsenal.
以冷战为例，当时美国抵御苏联核袭击的能力显然比今天更为脆弱，但“确保相互毁灭”战使得双方都变得同样脆弱，从而避免了灾难发生。苏联人虽然武力强大，但却无法利用手中的军火库从美国人处夺取任何权力。