On some questions, emphasis on the surprise-attack problem May lead to a downright reversal of the answer that one would get from moretraditional “disarmament” considerations. Consider the Case of a limitation on the number of missiles that might be allowed to both sides (if we ever reached the point in negotiations With Russia where an agreement limiting the number of missiles Were pertinent and inspection seemed feasible). Suppose we had decided, from a consideration of population targets and enemy incentives, that we would need a minimum expectation of to missiles left over after his first counter-missile strike in order to carry out an adequately punitive retaliatory strike — that is, to deter him from striking in thefirst place. Forillustration suppose his accuracies and reliabilities are such that one of his missiles has a 50-50 chance of knocking out one of ours. Then, if we have 200, he needs to knock out just over half; at 50 per cent reliability he needs to fire just over 200 to cut our residual supply to less than roo. If we had 400, he would need to knock out three-quarters of ours; at a 50 per cent discount rate for misses and failures he would need to fire more than twice 400, that is, more than 800. If we had 800, he would have to knock out seven-eighths of ours, and to do it with so per cent reliability he would need over three times that number, or more than 2400. And so on. Thelarger the initial number on the “defending”side, the larger the multiple required by the attacker in order to reduce the victim’s residual supply to below some “safe” number.

Thomas C. Schelling, The strategy of conflict, Cambridge, MA, 1980, p. 246