This chapter discusses defences, which are a fundamental part of criminal law, and reflect important limitations on the proper scope of punishable conduct. It is the purpose of this chapter to set out and critique the law relating to defences, in both treaty-based and customary international law. This chapter is concerned with substantive defences; it does not deal with issues such as immunity, youth, ne bis in idem, or limitation periods.

Chapter 5 commences by retracing how, beginning in Nuremberg, the reasonable person entered the battlefield in the form of the reasonable military commander. Subsequently the chapter explores two challenges that confront the concept of the reasonable person on the battlefield and beyond. The first challenge consists in the fact that it is easier to empathise with people who are close to us. In the theatre of war, this raises the question whether the reasonable person, when acting as the reasonable military commander, can meaningfully balance the interests of civilians on opposite sides. The second challenge relates to the fact that it is more difficult for powerful people such as military commanders (or judges) to take the perspective of others and to empathise with them.

Chapter 2 outlines the contemporary legal framework of IHL, examining the treaty and customary laws that govern conduct in armed conflict, and exploring the fundamental principles of the law. The distinction between the jus in bello and the jus ad bellum is explained, as well as some of the different terms used in IHL (Hague Law, Geneva Law, war vs armed conflict, etc). The main sources of IHL are explained – treaties and customary international humanitarian law. The chapter then explains the main principles governing IHL – distinction, discrimination, military necessity, proportionality, prohibition on unnecessary suffering, neutrality and humanity.

Accounts of the historical origins of international humanitarian law (IHL) routinely assume that the emergence of humanity as a constraint on the waging of war, coinciding as it did with a general rise of humanitarianism in the nineteenth century, reflected a growing commitment to a universally shared notion of human dignity. That assumption is fallacious. Those who have been mythologised as champions of humanity as constraint, including Henri Dunant and Francis Lieber, were products of their era. IHL’s ‘original sin’ was to only extend constraints of humanity to so-called civilised nations in their wars inter se. These same constraints were not intended to apply to indigenous and other colonised populations – those assumed to be ‘uncivilised’ – often referred to as such with the pejoratives ‘savages’ and/or ‘barbarians’. The exclusion of emergent constraints on the grounds of racism and colonialism is evident in the language of the early IHL treaties. It has taken many decades for the international community to overcome the exclusions of the legal protection of emergent IHL and some would argue that the tendency for exclusion is still evident in the dehumanising of the other in the Global War on Terror.

Humanity and civility were established as new leading principles of international law during the last decades of the nineteenth century. But the restriction of war itself was a battlefield. Some authors conceptualised the restrictions on warfare explicitly as of a social custom quality or as ‘chivalric practices’ of ‘moral value only’. Probably the most fundamental attack on international law’s limits came from the idea of ‘military necessity’. It was limiting law’s limitations. And in its most radical variant, it was evoked not only in those cases which explicitly referred to it but in any regulation of warfare. This was a specific, particularly militaristic understanding of ‘necessity’, and its effect was unleashing: the laws of war would lose their binding force. Necessity could revocate any ties, be they moral or legal. Pre-1914 international law was in some areas pretty far away from humanisation, universalism, and also from positivism. It was relativising and legitimating excessive violence.

Chapter 6 has three interrelated aims. First, to identify the relationship between the modern nation-state, international humanitarian law (IHL), and notions of civility; second, through a historical exploration of the relationship between military necessity, proportionality, and discrimination in IHL, to make the argument that the claimed shift from sovereignty to humanitarianism is not as complete as often argued, and that rather, raison d’état continues to be a motivating factor informing constraint during combat; and third, through an exploration of ‘the standard of civilisation’, to identify how this relationship informs discord between the universal underpinnings of contemporary IHL, and ongoing violations of the law. The chapter concludes by proposing that the oft-maligned concept of a ‘standard of civilisation’ remains valuable in exploring continuities of double standards as they relate to protections afforded by the modern laws of war.

According to a well-established rule of the law of armed conflict, warring parties are prohibited from employing weapons, means, and methods of warfare of a nature to cause superfluous injury or unnecessary suffering. Agreement about the foundational nature of this rule can, however, easily conceal the disagreement as to its precise meaning and efficacy. This paper considers the origins of the rule in question, and how key aspects of the rule are interpreted. It then examines one of the more contentious issues about the rule, namely whether it is only concerned with the inherent properties of particular weapons or whether it also deals with the use of weapons generally.

The centrality of slavery in the North and South, Black resistance, and the greatest shift in the domestic use and formation of federal force form the foundation of Chapter 7. Here, the likes of Robert Smalls, an enslaved boat pilot in South Carolina, the hundreds of thousands of Civil War slave fugitives, Union and Confederate military leaders, President Abraham Lincoln, President Jefferson Davis, and others address the consequences of one question: should the United States deploy its forces, its violence, in support of slaveholders or freed slaves?

This chapter formulates guidance for applying the IHL proportionality rule by looking at its objectivity; the standard of the reasonable commander and the interpretation of the term ’excessive’.

This chapter contains an analysis of the practical application of the IHL proportionality rule by looking at a number of examples of factual situations.

This chapter contains an overview of the development of the IHL rule on proportionality in treaty law and a discussion of its existence as a customary IHL rule.

In addition to the IHL proportionality rule, IHL contains a number of other rules that fulfil a similar role as a standard of moderation and with a broader scope, including effects on enemy forces.

This chapter provides insight into the practical and legal context in which the proportionality rule must be applied: the targeting process; indiscriminate attacks and precautionary measures.

The aim of this chapter is to assess the different factors which comprise the IHL proportionality rule.

Introduction to the study of proportionality rule in international humanitarian law.

IHL proportionality as a principle of IHL and the manifestations of proportionality in other legal frameworks relating to the use of force.

This chapter pleads for a refocussed application of the IHL proportionality rule, tilting the balance more towards humanity; and analyses whether it needs to be clarified or changed.

An inquiry into the rationale for the protection of animals in wartime confronts a key challenge: tThe progressive philosophical reflection on the improvement of the position of animals in (human) societies is at odds with the human-centred nature of international humanitarian law. Against this background, the chapter critically engages with possible reasons for animal protection in wartime: anthropocentric approaches, speciesism, anthropomorphism and a rights-based approach. It analyses to what extent these paradigms are reflected both in lex lata and in claims de lege ferenda. The chapter also examines to what extent these approaches can be brought in line with the overall objectives of international humanitarian law and reflects upon the challenges that arise from such an alignment. It favours a straightforward reform approach which aims at a specific convention for the protection of animal rights in wartimes.

Chapter 5 commences the book’s analysis of the operation of the most important investment treaty standards in armed conflict. It focuses on so-called war or armed conflict clauses. These provisions, present in many investment agreements, establish state obligations vis-à-vis investors who have suffered losses during armed conflict and other emergencies. Considering recent arbitral practice in the context of the so-called Arab Spring, the chapter gives guidance on how to understand these understudied clauses, their specific elements as well as their systematic function. While ‘basic’ armed conflict clauses establish a duty of non-discrimination in case the host state compensates other investors for losses suffered, ‘extended’ clauses give a standalone right to claim compensation for certain losses. These clauses convey such a right, among others, in case of requisitioning or unnecessary destruction at the hands of the state’s authorities or armed forces. The chapter shows how the general rules of attribution as well as the rules of international humanitarian law should crucially inform the application of these extended armed conflict clauses.