Absorbing the first strike (against military targets primarily) with a survivable retaliatory capability has been U.S. strategic posture since the 1960s with Gen. Curtis LeMay. The Russians have no use for Mutual Assured Destruction; they are interested in a counter-military strike. Their metric is the "correlation of forces," which is how they stand vs. the U.S. after the first exchange. There are not enough nuclear weapons in either arsenal to threaten more than 20% of each other's population, even if we wanted to. Too many small targets. Don't confuse Russian practical strategy with U.S. melodrama fantasies of total destruction.