Intelligent machines – from automated robots to algorithmic systems – can create images and poetry, steer our preferences, aid decision making, and kill. Our perception of their capacities, relative autonomy, and moral status will profoundly affect not only how we interpret and address practical problems in world politics over the next 50 years but also how we prescribe and evaluate individual and state responses. In this article, I argue that we must analyse this emerging synthetic agency in order to effectively navigate – and theorise – the future of world politics. I begin by outlining the ways that agency has been under-theorised within the discipline of International Relations (IR) and suggest that artificial intelligence (AI) disrupts prevailing conceptions. I then examine how individual human beings and formal organisations – purposive actors with which IR is already familiar – qualify as moral agents, or bearers of duties, and explore what criteria intelligent machines would need to meet to also qualify. After demonstrating that synthetic agents currently lack the ‘reflexive autonomy’ required for moral agency, I turn to the context of war to illustrate how insights drawn from this comparative analysis counter our tendency to elide different manifestations of moral agency in ways that erode crucial notions of responsibility in world politics.

Despite a recent explosion of interest in the ethics of armed conflict, the traditional just war criterion that war be waged by a “legitimate authority” has received relatively little attention. Moreover, of those theorists who have addressed the criterion, many are deeply skeptical about its moral significance. This article aims to add some clarity and precision to the authority criterion and the debates surrounding it, and to suggest that this skepticism may be too quick. The first section analyzes the authority criterion and reveals that there are at least two distinct moral claims associated with it, each requiring separate evaluation. The second section outlines an increasingly influential “reductivist” approach to just war theory, explaining how this approach grounds powerful objections to the authority criterion. The third section sketches the most promising strategies for providing a qualified defense of authority, while acknowledging the further questions and complications these strategies raise. Importantly, the article aims to rehabilitate the authority criterion from within a broadly reductivist view.

This chapter begins with the observation that non-international armed conflicts pose serious challenges to the efforts to regulate war in both international law and recent ethical discourse, and argues that neither has responded well to these challenges. Various problems in both are identified. The second part of the chapter examines the historical conception of just war accepted as consensual in the West from the high Middle Ages till early in the modern period, arguing that it provides a helpful frame for thinking ethically about non-international armed conflicts. The third section of the chapter carries this reasoning forward, applying it to non-international armed conflicts generally and to the problem of detention in such conflicts specifically.