How can states resolve problems with uncertainty? The most basic way is simply to ask. This chapter shows the unfortunately inherent limitations of such a strategy. If types were to reveal their private information truthfully, weaker types would receive fewer concessions. In turn, those types have an incentive to misrepresent themselves as stronger. Such a desire to take advantage of cheap talk communications continues when mediators are involved, though mediators with their own private information and the right type of bias may see some success.

This appendix describes the implicit function theorem and how it is useful for drawing comparative statics for equilibria that we cannot describe with an explicit functional form.

Chapter 1 provides an exposition of the general breadth and scope of the contemporary prohibition of the threat or use of force. After setting the prohibition in its historical context, it then examines the sources of the prohibition and its status as a ‘peremptory’ or ‘jus cogens’ norm of international law and what this means in terms of the prospects for its adaptation and modification in the future. While much focus has been traditionally placed upon the use of force, by comparison relatively little attention has been given to the threat of force, despite both coming under the contemporary rule against force. As such, the chapter sets out and provides an examination of the concept of a threat of force. While the prohibition is of undoubted importance, the decentralised nature of the international legal system means that accountability and responsibility for its violation are uncertain. The chapter seeks to examine this issue in detail, while also providing attention to the ‘human element’ to the prohibition, as well as assessing the continued relevance and effectiveness of the norm.

A dear friend who had stage four cancer told me how few, if any, of her friends and family were prepared to take the time to listen to what she was going through and enter into the reality of her situation. Existing as she did on a precipice between life and death, she felt alone and unheard. Instead of listening, friends and family rushed to offer either platitudes or crazy cures (eating kale being a memorable one) or find reasons that explained away what was going on and thereby dissolved their own dis-ease. Her situation demanded paying attention to what was actually going on, however uncomfortable or bewildering it was.

This chapter explores an underappreciated component of the risk–return trade-off with incomplete information. A central determinant of a state’s willingness to make risky proposals is how much it must overpay weaker types to obtain stronger types’ compliance. When this "peace premium" is large, riskier proposals look more attractive. However, given the right type of uncertainty, increasing the costs of war or decreasing a state’s resolve can counterintuitively increase the probability of war. We also explore a new type of uncertainty: how much value the winner of the war will receive.

Chapter 8 seeks to untangle various issues in addressing when and how a state might be able to resort to the use of force in self-defence against non-state actors. It firstly raises some important general considerations in relation to self-defence against non-state actors, before moving on to examine the situation of self-defence measures which target both the non-state actors and the host state, as was the case with the United States’s response to the terrorist attacks of 11 September 2001. A distinction needs to be made between self-defence taken against both the non-state actor perpetrators of the attack or those posing a threat and the state within which they are located, and those actions that are more limited in only specifically targeting the non-state actors. The chapter finally addresses the particular phenomenon of so-called targeted killing, which engages not only the jus ad bellum, but also the legal framework of international human rights law and, potentially, international humanitarian law.

The purpose of this chapter is to examine the use of force under the auspices of the UN, in particular the Security Council. Chapter 3 first sets out and examines the relevant provisions of the UN Charter and the division of competence between the various organs of the UN – the Security Council, the General Assembly and the Secretariat – to provide an understading as to how force was originally envisaged as being employed under the auspices of the UN. Given the Security Council’s primacy both within the Charter and in practice, the chapter goes on to examine the specific powers of the Council in relation to the use of forcible measures within the Charter and the limitations imposed upon these. Following this it then examines how these powers and responsibilities have been implemented in practice in both the Cold War and post-Cold War era. In particular, it has developed the practice of ‘authorising’ states, coalitions of states and regional organisations to use force to implement its mandate. The chapter finally addresses the relationship between the UN and regional – and, by extension, collective defence – organisations in the context of the use of force.

James Rebanks’s grandfather took pride in the careful way he watched and judged what was occurring each day with the land and livestock he farmed. Rebanks writes that when his grandfather stood looking over a gate, “he was figuring these things out by close and thoughtful observation.” In a meditation on the changing nature of the relationship British farmers have with the land they till and the animals they keep, Rebanks notes that this kind of deep attention is disappearing. “Managing animals the traditional way required specialist knowledge and judgment, and skilled people to care for them and understand their needs.” In an age of factory farming, such expertise “didn’t scale up easily for mass production.”

When my father died, my family and I needed a way to house and express our grief, bury his body, and gather with others to remember him. We could not conjure funeral practices out of nothing for ourselves; and even if we could have, we did not have the energy to do so. We were also confronted with having to navigate a vexed and primal moral question: What constitutes good care for the dead? Our tradition gave us words (Scripture and prayers), a ritual process (liturgies and funerary rites), institutions (the church and municipal cemetery), practices (bedside visitation by the priest, last rites, burial and memorial services), and virtues (truthfulness, hospitality, faith, hope, and love) for answering this question. It provided us with moral means to fulfill moral ends in a time of trouble.

Chapter 6 provides an overview of the general aspects of the right of self-defence. It first examines the concept of an ‘armed attack’ as found in Article 51, with the aim of shedding some light on the difficult issues and questions raised by this prerequisite for the invocation of the right of self-defence. It then goes on to provide an examination of the twin customary principles of necessity and proportionality, including a specific look at the controversial concept of armed reprisals, before moving on to examining military action for the protection of nationals who are located abroad. The right of self-defence exists in both individual and collective forms, and the chapter takes a specific look at the right of collective self-defence. Finally, it examines the role of the UN Security Council in the invocation and implementation of the right of self-defence, an aspect of the right which is prominent throughout Article 51.

Many students I’ve taught have been subject to legalistic and harmful forms of judgmentalism in either their church, community, or online interactions. In reaction against that legalism, they tend to practice a relativistic “you do you” approach to moral questions. In the name of tolerance and freedom, they see morality as a purely personal matter and are hesitant to make moral judgments about their own actions, let alone those of others. Yet this “live and let live” mentality undermines the pursuit of love and justice.

This chapter introduces the second general class of bargaining failure: information problems. If one side does not know how costly the other side views war, it may make an onerous demand. Opponents that have low costs reject, leading to war. Although this explanation for conflict is well known, many of its implications are misunderstood. The remainder of the chapter dispels some of them, showing that the probability of war can change as a function of the distribution of power and that more information might cause more conflict.