A Calculus of First-Strike Stability

For analyzing the merits of alternative strategic nuclear force postures, first-strike stability is a more relevant and demanding criterion than deterrence. First-strike stability exists if neither superpower perceives the other as motivated to strike first in a crisis. This Note describes an approach for evaluating the first-strike stability (or instability) of various postures of superpower strategic offensive forces. The study uses a calculus of the cost of striking first compared with the potential cost of waiting and risking an enemy first strike. The analysis suggests that the current postures of U.S. and Soviet strategic offensive forces do not demonstrate any undue degree of first-strike instability. However, merely reducing the level of U.S. and Soviet offensive forces does little to enhance stability and may actually increase first-strike instability because the types and posture of forces deployed have a greater effect on stability than do their overall numbers. To maintain stability, reductions in offensive weapons should be coupled with improved basing modes.