AbstractThe problem is to protect a set ofttargets bynperfect interceptors against an attack bymperfect weapons. If the defender solves for an optimal preallocated preferential defense and associated game value assumingm1attackers, and the attacker knows the assumption of the defender and utilizesm2attackers, he may be able to achieve significantly more damage than had the defender assumed that there would bem2attackers. The article treats the robustness of preallocated preferential defense to assumptions about the size of the attack and presents results of an alternative approach.