Interventions on the intersection between security and ethics have become increasingly common in academic literature in the field of international relations. Yet most of this literature tends toward articulating and defending a particular account of “security,” rather than examining the ethical commitments and limitations of different accounts. And despite a stated interest in exploring the intersection between security and ethics, most literature on this topic tends to draw only marginally on philosophical frameworks or forms of reasoning and argumentation informed by philosophy. David Welch’s book corrects both these tendencies, with a systematic philosophical investigation of alternative accounts of security. In the process he makes a case for the priorities that should guide state policy makers when allocating resources for the pursuit of security.

This book begins by outlining and defending a definition of security as “an objective condition of relative safety from harm” (p. 18). The author is aware that this focus on “objective” security stands in contrast to approaches more interested in the subjective construction of security or securitization, making the case that “accurate threat perception” (p. 31) should inform the way security issues are prioritized and addressed. Having laid this foundation, the book then develops a theory of value, distinguishing between intrinsic and extrinsic (or instrumental) value. This gives us a framework for making sense of what priorities should inform our approach to security and its provision. This discussion, which includes a reflection on the anthropocentrism of existing security thinking and practice, concludes with the argument that “decisions about security should generally reflect good-faith best efforts to promote and protect the conditions under which both humans and non-humans can experience the things that make life worth living” (pp. 55–56).

From this point the book explores four referent objects of security: the ecosphere, states, culture, and humans. A chapter is devoted to each, with each discussion critically examining the nature of this referent object’s value and to whom. The discussion of ecospheric security makes clear that the intrinsic and extrinsic value provided by a functional ecosphere is such that it should take precedence as a security referent. This analysis ranges from a discussion of immediate threats to ecosystem functionality to the challenges of climate change and even responses to it, not least in the form of geoengineering. “Our duty of care to the ecosystem,” the chapter concludes, “is a duty second to none” (p. 90). In the chapter on state security (prioritized as a terminology over “national security”), the author is clear that the value of states is largely extrinsic, rather than intrinsic. But given their formidable resources it is important to recognize, the author argues, the capacity of the state to perform important functions (including for the ecosphere), even if there is an historical tendency for states to prioritize marginal challenges to state sovereignty such as terrorism.

This book’s choice of “culture” as a referent object is surprising on the face of it. But the author makes a strong case for the (exclusively extrinsic) value of culture for people as members of communities, linking this discussion to recent literature on the concept of ontological security in international relations. This discussion weaves between a range of possible threats to culture from genocide to language loss, cultural appropriation, and ontological insecurity. The final substantive chapter engages with human security, adroitly contrasting a coherent and ethically defensible account of a focus on the security of humans with the UN Development Program’s seminal definition of human security. In the process, the author makes the case that human security should be about protecting individuals (not communities) and defines human security in terms of Abraham H. Maslow’s basic needs of safety and physiological needs (“A Theory of Human Motivation,” Psychological Review 50 [4], 1943). The conclusion reflects on the themes of the book in relation to their future prospects, with the author expressing pessimism about the possibility of optimizing the use of security resources but optimism about the prospect of significant improvement.

If there is one lingering question in reading this book, it relates to the author’s stated goal of informing (and bettering) political choices around the allocation of resources in pursuit of “security.” The book makes a compelling case for the principles that should inform this allocation, orienting around the need to ensure ecospheric security in the first instance. Yet the gap between a strong and well-defended case in an academic text and substantive outcomes in practice is, of course, significant.

The book suggests that, if only we subjected decision making about the pursuit of security to rational cost-benefit analysis based on core philosophical principles that we could agree to, then we would see political choices that allocated resources effectively, thereby minimizing harm and genuinely advancing “security.” But a case for rationality in this context only gets us so far (some would say not far at all!) in understanding how political leaders can and do choose to prioritize particular threats and particular responses to them. And it is intuitively difficult to accept the idea that this is simply a matter of political leaders getting their calculations wrong. Rather, a strong case can be made that political leaders are constrained in their capacity to pursue innovative approaches to security and its provision by prevailing societal expectations, existing international norms, or resource availability, for example.

In the book’s case for a rational allocation of resources and in its more limited engagement with the political constraints facing a revisioning of security in practice, what seems to be missing is an account of how we might get from where we are now to where the author wants us to go. Essentially, what’s missing is an account of politics. Simply put, how might the sets of priorities articulated in this book move (and be moved) from academic principles to political practice? However, there is certainly a case for the principles outlined in this book to inform subsequent work on this topic, which might directly address this question of praxis and could help realize this book’s stated concern of informing policy and practice.

That said, this remains a genuinely important contribution to the literature on security in international relations. It compels readers to reflect on their own assumptions about security “values” and develops a coherent and compelling case for an account of security that prioritizes the protection of the ecosphere. In defining security as an objective condition, along with engaging in a critical examination of the literature on ecospheric, state, cultural, and human security, the book poses a challenge to much contemporary scholarship and even to the way we think of the field of security studies. In this sense the author makes himself a large target—but this is also what makes this book important.