Page 18be politically feasible under certain likely specified future situations. At each stage, we assume that overall parity between the United States and the Soviet Union would be maintained, if only for the sake of political stability, although parity among the individual components of the force (such as submarines or mobile missiles) would not be necessary.
These deterrence policies would continue the dependence we have had on offense-dominating defense, that is, on “offense-dominated stability.” In principle, there could be “defense-dominated stability” if technology permitted nations subject to nuclear attack to prevent the arrival of nuclear weapons through adequate defenses. This is not the place to discuss critically the long-range technical prospects for converting the current offense dominance to a defense-dominated world or to examine whether a transition to such a world could be executed stably. The advent of nuclear weapons has strongly tilted the traditional offense-defense competition in favor of the offense since each delivered nuclear weapon possesses such great explosive power. This fact, combined with the wide variety of means to deliver nuclear weapons and to ensure that they reach their targets, has led to the present situation. No technical developments are expected to upset this condition in the foreseeable future.