International Conventions and Non-State Actors: Selection, Signaling, and Reputation Effects *

Abstract Non-state actors (NSAs) play an important role in contemporary violent conflicts, but cannot generally sign international conventions open only to state actors. The non-governmental organization Geneva Call solicits NSAs to sign conventions that tie their hands and ban particular activities, for example the use of landmines, and to allow monitoring of their compliance. This specific case highlights general questions over why non-state actors should sign conventions that limit their autonomy and cannot be enforced, and whether such conventions can change subsequent behavior. We propose a game-theoretic model to assess the motivations for NSAs and states in armed conflict to sign conventions and how they affect subsequent conflict behavior, considering the costs of foregoing mines as well as possible reputation costs. We find that decisions to sign hinge on expectations about whether the antagonist will sign, and that actors can signal resolve through signing and under some circumstances for the other party to sign and comply. Empirical analyses of conflict behavior in countries where Geneva Call has been active support the implications of the theoretical model, once we take into account selection issues.