The introduction offers a historical overview of terrorism through the ages and describes the development of international counterterrorism law. It discusses the interplay between terrorism and international crimes such as genocide and crimes against humanity. It also introduces some of the controversy surrounding terrorism as a term.

This Introduction begins by outlining what is meant by international relations. It then tells the story of how and why the academic study of international relations emerged in the early twentieth century before considering the need to ‘globalise’ the study of international relations – to make it an academic discipline more open to non-Western perspectives. It sketches the changing agenda of international relations, a shift that some scholars describe as a transition from international relations to world politics or from the ‘traditional’ to the ‘new’ agenda. Although there is little doubt that, as political reality has changed, new theoretical tools have become necessary to grasp it, we should not assume that the myriad changes in our world have rendered the ‘traditional’ agenda obsolete. As we shall see, the ‘new’ agenda supplements, but does not supplant, the ‘traditional’ agenda. It is now more important than ever to consider the relationships between ‘traditional’ and ‘new’ agendas, and to globalise IR.

This chapter provides a brief introduction to the ethics and laws of war. The first part outlines what international law and the ‘just war’ tradition say about war; the second explores the conduct of war; and the third examines two recent dilemmas as examples of moral and legal debate: the legitimacy of pre-emptive self-defence and the use of cluster bombs.

This chapter introduces the concept and practice of security in international relations. It explores the dilemmas faced by states, individuals and the global community by first looking at contemporary crises and disagreements about security; second, examining how security has been differently defined and focused; and third, surveying how different theoretical approaches have understood and analysed security.

Liberalism is at the heart of modern ‘Western’ history, politics, and international relations. Central to understandings of liberty, freedom, democracy, rights and the rule of law, liberalism has animated debates on abolition and empire, war and peace. This chapter provides an account of liberalism as a contested phenomena that originated at least in the eighteenth century and has had profound international political consequences ever since. To tell this story, the chapter begins by considering how to make sense of the contestations surrounding liberalism, before examining how and why liberalism matters to International Relations at key moments of its development as a discipline: in the age of empires, the inter-war years, during the Cold War and ‘new’ world which ensued, and now in this epoch of endless war.

The debate about whether state or non-state players have primacy has been a major preoccupation for International Relations researchers. This chapter argues the key is not so much to determine which players are dominant, but how they interact to produce the prevailing order. The 1985 book Bringing the State Back In declared the return of the state for international politics and political economy (Evans et al. 1985). This chapter argues instead for bringing state–society relations ‘back in’ to the centre of what makes international relations.

International law governs almost every facet of international life, from the mundane to the complex. This chapter discusses the role of international law in world politics. It begins with a discussion of the content of international law, explaining the sources of law and how we identify them. It then addresses the question of why the study of international law is foundational to the study of international relations. The chapter offers two answers to this question. First, international law is important in the study of international relations because the nature and extent of its influence are among the core debates in international relations theory. Second, the study of international law is important because law is at the heart of many international disputes today. The chapter concludes by considering two examples of ‘law in action’: the legal decision regarding Chinese activities in the South China Sea and the contemporary debate over membership of the International Criminal Court.

This chapter explains the legal and political features of the United Nations. It begins with a short introduction to the UN Charter, which shows the framework of international law that defines, limits and empowers the organisation. It then puts these into a more practical setting, which emphasises how the United Nations is at the same time an actor, a forum and a resource for governments.

Processes of arms control and disarmament remain relevant in a world where armed conflict between states is still highly visible in international politics, and where civil wars and domestic conflicts claim hundreds of thousands of lives every year. Much attention is focused on the need to control and eliminate weapons of mass destruction (WMDs), especially nuclear weapons, given the hugely destructive nature of these armaments, but controlling so-called ‘conventional weapons’ – those not classed as WMDs – is also important. Conventional weapons, especially small arms and light weapons, are responsible for most of the casualties we see today, even as arms control efforts have only recently begun to focus on these.

By way of conclusion, this chapter seeks to provide an overall assessment of what draws the Court and the Commission together, and of the impact that their “special relationship” has produced. In pulling the threads together, it explains that the interaction between the two organs has turned out differently to that which was originally envisaged, and that the great weight accorded by each of them to the work of the other has challenged the exclusive basis of State consent for international law’s validity. In a legal system that remains heavily dependent on unwritten rules of customary international law that require authoritative determination, the ultimate result has been that the Court and the Commission together assume a public order role not foreseen for either of them by their founders.

This chapter provides a detailed account of the impact that the Commission’s work has had in shaping the Court’s case-law. In addition to surveying and classifying all those instances in which the Court has to date been ready to refer expressly to the Commission’s output, the chapter demonstrates that reliance on the Commission’s work has often been more implicit. The question is then posed as to the basis for such recourse and the advantage afforded by it.

Chapter Six looks at the role of international law in the Trump administration State Department. Former policymakers gave their opinion on the extent of the effect of the Trump administration on State Department policymaking and discussed potential long-term effects. The Trump administration generally displayed a negative view toward international law, institutions, and agreements, as evidenced by its words and in its actions, a view at odds with the prevailing State Department culture. More significantly, the Trump administration took unusual steps to stifle dissent within the State Department. Former officials expressed a range of perceptions regarding the Trump administration’s effect on the State Department. A minority believed that the administration’s views and actions significantly affected attitudes and practices within the Department regarding international law and institutions. The majority believed that effects on attitudes were more likely to be felt at the policy-decision level, rather than at the lower, policy development level. That is, attitudes among rank-and-file and career State Department officials probably remained unchanged and were likely to “bounce back” after the 2020 election. Nevertheless, a reprise of the Trump administration, or a similar administration, could ultimately affect not only practices at the State Department but attitudes among officials as well.

This chapter sets the scene for an appreciation of the contemporary relationship between the Court and the Commission by tracing its roots in the broader ideal of the pacific settlement of disputes and the rule of law in international affairs. Taking stock of developments dating back to the nineteenth century, it illustrates that the long-standing movements for an international court and for an international code were not unrelated, and that a certain vision did exist for the way in which their present institutional manifestations were to interact. That original vision, which has been lost in time, has thus far attracted less attention from commentators than its importance requires.

This introductory chapter explains the scope and purpose of the present study; the methodology pursued; and the structure of argument presented in subsequent chapters.