Because there is no international sovereign to guide international relations, states must rely on the cooperation of others to maintain the status quo. However, like other cooperation dilemmas, states will benefit most if they all cooperate, but will lose drastically if some states deflect. This dilemma differs from individual level dilemmas such as Rousseau’s stag hunt or the classic prisoner’s dilemma in that states fluctuate through changes in leadership and shifts in values. This article examines the dilemmas states face engaging in international cooperation. The author focuses specifically on the security dilemma: the fact that many of the means by which a state tries to increase its security decreases the security of others. Unlike individual relations, state security becomes a zero-sum game. Jervis outlines various game-theory approaches to the subject and outlines what makes cooperation among states more or less likely.