To launch these would guarantee a second strike on U.S. cities. Given these capacities, the Soviets could, even without a first strike, hold U.S. forces immobilized and in checkmate, freeing Soviet conventional forces from restraint. Nuclear weapons do not have to be fired in order to exact surrender.
The reasons why the United States maintains a strategic triad— land-based, airborne, and submarine-borne delivery systems—are two: first, to reduce the temptation of a simple first strike; and, second, to prevent the President of the United States from facing only a single option, the command to destroy Soviet cities. Such an option would be suicidal for American cities. No President can be fairly placed in that position.
In short, given the nature of the USSR's leadership, its ideology, and its political culture, and recognizing the configuration of its nuclear forces, we see no completely satisfactory position: neither abandonment of the deterrent, nor a deterrent strategy based upon counterforce, nor a deterrent based upon countervalue. Among these, we judge the best of the ambiguous but morally good options to reside in a combination of counterforce and countervalue deterrence. We uphold the fundamental intention of deterrence that no nuclear weapon ever be used. We uphold the secondary intention of being ready to use the deterrent within the narrowest feasible limits, as indispensable to making deterrence work. We reject the policy of national bluff that permits possession but does not permit its essential secondary intention. We discern no other way to defend the Constitution of the United States, to protect its institutions of liberty, and to prevent the most awful aggression against innocent peoples here and elsewhere. It would hardly be better for us if some other people bore this burden, but in any case there is none that can lift it from us. In due course, the Soviet Union may learn to prefer ways of peace abroad and ways of liberty at home—in which case, peace among nations may be possible. For this we labor and pray.