Introduction

This chapter discusses the shortcomings in the deterring terrorism literature followed by a closer examination of the scope and logic of deterrence in state versus violent non-state actors (VNSAs') deterrence interactions. It employs a life cycle approach to terrorism formation, and matches that with a longitudinal approach to evaluating strategic learning about how deterrence works between states and VNSAs. In the foreword to Andreas Wenger and Alex Wilner's Deterring Terrorism, Thomas Schelling observed that the United States government was slow to learn the rudiments of deterrence during the Cold War, expressing the hope that learning how to deter terrorism would proceed more rapidly. Answering Schelling's call, the deterring terrorism literature, generally divided into skeptics and marginalists, has made great progress and many new core concepts have been explored and added to the theoretical foundation of deterrence. The chapter also presents an overview of key concepts discussed in this book.