The Emerging Fourth Wave of Deterrence Theory-Toward a New Research Agenda

In this paper, I aim to review recent empirical and theoretical developments in the study of deterrence. I suggest that an emerging wave of literature currently represents a revival in this field. However, unlike the previous waves, in which theoretical and empirical questions were studied together (realism and nuclear deterrence), in the emerging deterrence literature these two are isolated from each other. The theoretical trend of this wave is evident in new constructivist and interpretative scholarship that explores the practices of deterrence and has provided significant insights, chiefly with regard to classical empirical questions of state versus state and nuclear deterrence. The empirical trend of this wave can be seen through the work of scholars who are considering how to deter "new" threats-such as terrorism, rogue states, and ethnic conflicts-mainly by incorporating the traditional realist approach to deterrence. By reviewing these two trends in the current wave of deterrence writing, I demonstrate the advantages of each and suggest that the study of deterrence may benefit from their integration.