The Elements of Deterrence is an ambitious book, which seeks to fundamentally change how we think about deterrence. Overall, it is successful in this aim, providing a broad framework for conceptualizing deterrence’s complexities and the tradeoffs inherent in achieving deterrence. The book covers a large range of topics, but the key theme is that different goals and practices fall under the umbrella of deterrence, and policymakers need to choose different strategies depending on their goals. The book begins by defining the concept of deterrence. The authors broaden the concept to include different political goals (political influence, military effectiveness, policy efficiency, and strategic stability) and strategies (coercion, defense, deception, and accommodation) that are not all typically considered part of deterrence. This sets the stage for discussing the challenges of deterrence in particular domains.
The domain that receives the most attention is cyberspace. The authors argue cyberspace is not very useful for coercion or defense but is useful for deception. They also discuss how cyber capabilities could undermine nuclear stability. The authors move on to discuss which factors contribute to deterrence success in the domains of land, sea, air, and space, devoting a chapter to each. Finally, the authors revisit the commercial peace argument, discuss how cyber attacks and conventional use of force complement each other, and consider the factors that promote gray zone attacks.
This book is timely and policy-relevant. As the authors show at the outset of the book, the U.S. government has struggled with the concept of cross-domain deterrence. We once lived in a world where deterrence was primarily discussed in terms of nuclear weapons deterring nuclear attacks. In modern times, the scope of what the US (and other countries) seek to deter has expanded. The question of how to deter cyber attacks has brought the concept of cross-domain deterrence to the fore. Gartzke and Lindsay argue, and most scholars would agree, that cyber capabilities are not very useful for deterrence because they are not transparent. But if cyber capabilities cannot deter cyber attacks, then what does deter cyber attacks? Is the threat of sanctions too weak? Is a nuclear threat too excessive? This is only the tip of the iceberg in terms of cross-domain deterrence questions. We might also wonder, for example, whether naval forces can deter land attacks or whether space capabilities can deter nuclear attacks?
For those seeking a policy manual for cross-domain deterrence, this book does not necessarily provide a straightforward recipe for successful deterrence in every situation. This is not so much a shortcoming of the book as a reflection of the world’s complexity. The book does offer some specific findings about what approaches are most effective in each domain. For example, there is strong evidence that troops on the ground contribute more to extended deterrence success than offshore troops. However, the book’s broader contribution is providing a structure for thinking about deterrence.
The book serves as a reminder to policymakers that the process of thinking about deterrence must begin with an evaluation of policy goals. After deciding what their goals are, policymakers must decide what strategy to use to achieve their goals, keeping in mind various tradeoffs. For example, coercion is a strategy for maximizing political influence, but it may come at the cost of strategic stability. After choosing a strategy, policymakers must finally decide which domain is most suitable for employing that strategy. Gartzke and Lindsay offer advice for linking goals and strategies, and they rank the appropriateness of different domains for different strategies. Overall, rather than providing situation-specific recipes for success, they provide principles that can be applied to any situation.
Beyond its policy contributions, this book makes important contributions to the literature on credibility. In recent years, this literature has had a strong focus on signaling and reputation. This book reminds us of something less commonly discussed: the role of military capabilities in credibility. Of course, there is no disagreement among scholars that military capabilities matter, and they are already captured in formal models of credibility and coercion. Yet little theoretical attention has been given to military capabilities, and even less attention has been given to which types of capabilities boost credibility the most. This book remedies that.
Another important contribution of the book is emphasizing the limits of deterrence. What is useful for deterring one type of challenge is not always useful for deterring others. This theme appears throughout the book, but the penultimate chapter on gray zone activities really drives it home. This chapter argues that the ability to deter conventional aggression may drive a potential aggressor toward gray zone activities instead. Yet more surprisingly, becoming good at combatting gray zone activities may spur an aggressor to pursue conventional aggression. The authors conclude, “We may be able to choose how our adversary confronts us, but not whether” (pp. 372, emphasis original). Readers may debate whether this conclusion is simply realistic or overly pessimistic. For those who would prefer to live in a world where we can deter both large-scale and small-scale harm, it poses a challenge for more research to figure out how.
It is worth noting how this book is different from most contemporary political science books. Most books today are about a single idea, which can sometimes be summarized in as little as one or two sentences. Such books devote their pages to developing the theoretical underpinnings of their idea and testing them in many different ways. Gartzke and Lindsay’s book is more ambitious and has many different ideas running through it. There is great value in a book that covers this much ground and provides such a broad picture. Indeed, the book harkens back to classic—and highly valuable—work on deterrence by scholars like Thomas Schelling in its broad scope. However, the broad scope does come with some tradeoffs. Most arguments are not subject to more than one empirical test. Some ideas, such as about which domains are best for which strategies, are left largely untested. Finally, the empirical tests are only briefly described—although more details about many of the tests are available in the authors’ previous journal publications.
This is not intended as a major criticism of the book, as such tradeoffs between breadth and depth are inevitable. Readers who are seeking a broad picture and a bold vision will be pleased with this book. Readers who seek a deep dive into a particular aspect of deterrence may be less satisfied. In the best case, this will spur more research to fill in the gaps in the big picture painted here.
