Defensive Realism

Abstract Chapter 15 is about defensive realism. Exponents of this theory see the international system as one that, in general, does not facilitate expansionism. The specific form that the quest for power takes under such circumstances is pursuit of security. Three theories about the causes of war, each with an overlapping set of contributing factors, fit within defensive realism. The first theory emphasizes first-mover advantage as a property of the international system that can set in motion processes that threaten its stability. A second theory focuses on windows of opportunity, which aggressor states, figuratively speaking, may jump through in pursuit of gains at the expense of others. Third, and finally, the offense-defense balance possesses potential to destabilize a system. The dangerous situation is one in which the offense is at an advantage, whereas dominance for defense is less likely to encourage efforts toward conquest.