Philosopher John Kaag and political scientist Sarah Kreps share the concern that drone technology is developing faster than our ability to understand its implications. The result of their collaboration, Drone Warfare (2014, Polity Press) is an interdisciplinary synthesis of the legal, political and moral arguments surrounding the United States’ use of armed drones to conduct targeted killings of suspected terrorists. Their treatment of US drone policy, while largely critical, is nevertheless more measured than some other recent books that have dealt with the topic, such as Medea Benjamin’s Drone Warfare: Killing by Remote Control (2012) or Grégoire Chamayou’s A Theory of the Drone (2015). Kaag and Kreps, far from calling for an outright ban on the technology, are confessedly pragmatic: ‘Perhaps they are a necessary evil, but part of this book is meant to determine how necessary and how evil' (p. 13).

Kaag and Kreps concede that drones are a precise weapon system that is tactically successful at attacking Al Qaeda and other terrorist groups while minimizing American and civilian casualties. In this regard, drones are a positive development and may even have ‘significant utility…in very specific scenarios’ (p. 51). Nevertheless, they conclude that the long-term consequences of the United States’ drone policy is deeply troubling for normative as well as practical reasons. Despite apparent short-term success, they characterize American drone warfare as a strategic failure, which is most evident in the form of ‘the visceral opposition’ that they create among targeted populations in the Middle East (p. 14). But blowback is not the main thrust of their argument. In subsequent chapters, Kaag and Kreps demonstrate that the failure of drone warfare has troubling consequences for democracy, international law and ethics.

One of the reasons that drones are so attractive is that they effectively lower the costs of war for democratic countries. Although fiscal savings are important, the real advantage occurs at the level of domestic politics. Waging war with drones allows democratic governments to avoid negative publicity from friendly casualties, sidesteps the question of what to do with captured terrorists and apparently enjoys strong support from the citizenry itself. Poll data suggests that a majority of Americans support drone warfare, even if they do not know much about it (see Table 3.1, p. 62). More troublingly, Kaag and Kreps argue that the evolution of drone policy in the US has been marked by the erosion of traditional democratic checks and balances. Neither Congress nor the judiciary has exercised adequate oversight over the executive branch’s use of drone strikes. Ultimately, drones threaten to detach war-making from the democratic constraints that have traditionally regulated it and thus expose ‘a loophole in Kant’s democratic peace theory’ (p. 65)

Although the Obama administration characterizes its drone policy as compliant with international law, Kaag and Kreps argue that aspects of it actually violate the requirements of both  jus ad bellum—the international legal principles governing when states may go to warand  jus in bello—the rules by which war must be conducted. First, the administration’s legal justifications for conducting targeted killings outside declared battlefields, such as Pakistan or Yemen, rely on overly broad interpretations of what constitutes self-defence and imminent threat. Second, even though drones are highly accurate weapons systems, the targeting decisions governing their use, such as signature strikes on unidentified individuals who are judged to fit a pattern of terrorist activity, and the overall lack of transparency surrounding death counts, raises worrying questions in regard to the principles of distinction and proportionality.

The chapter on the ethics of drone warfare steps back from specific legal and political issues and tackles the broader moral implications of killing by remote control. This technology creates a ‘moral hazard’ whereby policymakers and military personnel are increasingly drawn to risky behaviour because they do not have to worry about the consequences of their actions. In this fashion, the expediency of drone violence comes to overshadow the more important question of whether or not these strikes are morally right in the first place. Yet, Kaag and Kreps see a glimmer of hope. This new distance from the passions of hand-to-hand combat can create a space for the practitioners of remote warfare to potentially reflect on the moral and legal implications of their job. However, this will require new forms of training and a willingness to ask difficult questions. The alternative is a world in which drone strikes, and their long-term negative consequences, become increasingly commonplace. 

Written in accessible and clear prose, this book is  useful for anyone interested in learning more about the emerging issue of drone warfare. That said, this book is primarily aimed at an American audience. The pragmatic approach espoused by Kaag and Kreps revolves around calculated appeals to American self-interest, accentuated by the fear that proliferation is inevitably putting drone technology in the hands of a growing circle of foreigners. This frightening future, they warn, can only be avoided by American self-restraint and the creation of an international body to regulate the use of drones. In the end, this book implies that a reformed version of drone warfare will better sustain American hegemony than the model currently being followed.