Strategic Defenses and First-Strike Stability

The impact of strategic defenses on stability is a central theme in the Strategic Defense Initiative debate. This report examines the effects of defenses on first-strike stability. It is principally concerned with assessing first-strike stability during the transition from an offense-dominated strategic balance to a defense-dominated balance. It also examines the implications of various offensive and defensive force structures. The findings suggest that (1) first-strike instability during the defense transition can be minimized by careful force planning; (2) the most stable defense transition occurs when the ballistic missile defense transition is completed before significant levels of air defense are deployed; (3) arms control efforts will not necessarily reduce potential first-strike instabilities unless each side's counterforce capability is reduced; (4) asymmetries in each side's ability to suppress the opponent's defenses can lead to instabilities during, and after, the defense transition; and (5) biased perceptions make the defense transition either more or less stable, depending on the nature of the bias.