The Duty to Pay Reparations for the Violation of the Prohibition of the Use of Force in International Relations and the Jus Post Bellum

This chapter critically assesses the usefulness of a jus post bellum as a freshly discussed third pillar of international peace and security law with regard to a state’s duty to pay reparations for an unlawful resort to force. Based on the analysis of the relevant practice—starting from the Versailles reparations regime after the First World War and ending with the work of the Eritrea-Ethiopia Claims Commission at the beginning of the twenty-first century—this chapter identifies a systemic gap in the current legal framework governing the aggressor state’s reparations obligation. While the principle of full reparation is one of the fundamental premises to the law of state responsibility and firmly enshrined in customary international law, there is a recurring practice in the aftermath of armed conflicts to consider the severity of the aggressor state’s wrongdoing and its economic capacity in determining the adequate reparations sum. The chapter concludes that this practice, which reflects the unique peacebuilding function of reparations in a post bellum society, can be best addressed by developing and applying a jus post bellum principle of proportionality to the aggressor state’s reparations obligation.

Specifying the Proportionality Test and the Standard of Due Precaution: Problems of Prognostic Assessment in Determining the Meaning of “May Be Expected” and “Anticipated”

This chapter addresses the challenging legal and operational issues raised by the proportionality requirement to assess the legality of collateral damage. Specifically, the chapter engages closely with the relevant text of Articles 51(5)(b) and 57(2)(b) of the First Additional Protocol to the Geneva Conventions. The chapter first asks what makes an attack that unavoidably includes incidental loss of civilian lives or civilian property an “indiscriminate attack” under Article 51(5)(b). In more concrete terms, it asks how the formula for collateral damage—“excessive in relation to the concrete and direct military advantage anticipated”—may be operationalized. The chapter then moves to an analysis of the rule of precautions in Article 57(2)(b), with special emphasis on understanding how the military operator should navigate this rule in light of battlefield realities. The chapter then poses how these rules may be best understood under the regime of international criminal law.

Sequences of Military Necessity for the Jus in Bello

This chapter considers several discrete snapshots or “sequences” in the life of military necessity—as it has come to be understood within the laws of the jus in bello. Commencing with its relationship with self-preservation under the laws of war and peace, the chapter proceeds to examine the idea of “necessity” of self-defense within the laws of the jus ad bellum; it then turns to “military necessity” as invoked in the Lieber Code, the 1907 Hague Regulations, Additional Protocol I of 1977 and the 1954 Hague Convention, the ICRC Study on Customary International Humanitarian Law as well as the advisory jurisprudence of the International Court of Justice. Consideration is given, too, to “necessity” as it features within the law of State responsibility, in order to more fully understand the function, status and standing of “military necessity” more generally within the jus in bello.

Necessity and Proportionality in Morality and Law

This chapter offers a systematic analysis of the notion of proportionality in both moral philosophy and law, particularly the law of armed conflict. Proportionality is a constraint on different forms of justification for harming people. There are thus different forms of proportionality corresponding to different types of justification. The proportionality constraint should not be conflated with a different constraint—the necessity constraint—which in turn must be carefully distinguished from necessity as a form of justification. The chapter explains how the proportionality constraint and the necessity constraint are distinguished by the different comparisons they require. It further explains the relations between the requirement of proportionality in jus ad bellum and the requirement of proportionality in jus in bello and argues that the criterion of proportionality in the law of jus in bello is actually incoherent. The final section elucidates the various matters of moral theory that are relevant to understanding how the requirement of proportionality applies in practice to the action of combatants who fight in just wars.

Toward the Special Computer Law of Targeting

One of the implications of fully autonomous weapons systems (AWS) as an independent decision maker in the targeting process is that a human-centered paradigm should never be taken for granted. Indeed, they could allow a law of armed conflict (LOAC) debate immune from that paradigm all the more so because the underlying “principle of human dignity” has failed to offer convincing reasons for its propriety in international legal discourse. Furthermore, the history of LOAC tells us that the existing human-centered approach to the proportionality test—the commander-centric approach—is, albeit strongly supported and developed by states and international criminal jurisprudence, particularly since the end of the Second World War, nothing more than a product of the time. So long as fully AWS exhibit the potential for better contribution to the LOAC goals to protect the victims of armed conflict than human soldiers, one could thus seek an alternative computer-centered approach to the law of targeting—a subset of LOAC—tailored to the defining characteristics of fully AWS in a manner to maximize their potential as well as to make the law more responsive to the needs of ever-changing battlespaces. With this in mind, this chapter aims to relativize the absoluteness of the existing human-centered approach to the proportionality test—which is not to deny the role of humans in the overall regulations of fully AWS whatsoever—and then, away from that approach, to propose an alternative one dedicated to fully AWS for their better regulation in response to the demands of changing times.

The Proportionality Rule and Mental Harm in War

The foundational international humanitarian law rule of proportionality—that parties to an armed conflict may not attack where civilian harm would be excessive in relation to the anticipated military advantage—is normally interpreted to encompass civilian physical injuries only. Attacks may cause significant mental harms also, yet current interpretations of the law lag behind science in understanding and recognizing these kinds of harms. This article analyzes legal, public health, psychology, and neuroscience research to assess the extent to which mental health harms should and could be taken into account in proportionality assessments.

Drones Programs, the Individualization of War, and the Ad Bellum Principle of Proportionality

This chapter describes how drone programs facilitate the individualization of war and intensify the pressures put on the right of self-defense. Rather than using force in self-defense against an (imminent) act, some states active in the transnational war on terror use force in self-defense against individuals based on their personal characteristics. This strategy leads to authorizing action against individuals who are not presently perpetrating, nor even clearly preparing to engage in, threatening acts. The chapter argues that these changes are not merely the result of how states decide to use force in the context of counterterrorism but also are impacted by what technology allows them to do. As such, drones facilitate and arguably intensify these phenomena of individualization and dematerialization of the use of force. Focusing on one of the justifications for this practice, namely, the right of self-defense, the chapter argues that the framework articulated by some states active in the transnational war on terror, while still highly contested on some points, offers a framework for the continuous anticipation of armed attacks by individuals who show signs of continuing armed activity. The chapter shows that under pressure by state practice and rhetoric, some limitations on using force that were initially interpreted restrictively are currently interpreted extensively. More importantly, the chapter argues that even if some limitations remain, the concessions to the extensive interpretation appear to have a direct cascade effect on the remaining conditions precisely because these limitations are interconnected. It is ultimately shown that this cascade effect is epitomized by the principle of proportionality which is not only extended but transformed to adapt to the individualization of war.

The Unwilling and Unable Test for Extraterritorial Defensive Force

This chapter focuses on the defensive use of force against non-state actors located on the territory of a third state. The legality of such operations is among the most contested legal questions of our time. Few states question the legality of using defensive force against non-state actors per se, but the more contested question is whether such interventions are illegal as to the third state on whose territory the non-state actor resides, and on whose territory the intervening state must necessarily engage in military action if it hopes to defeat the non-state actor. A number of states, though not all, have coalesced around the standard that such interventions are permissible if the territorial state is unwilling or unable to resolve the threat posed by the non-state actor. This chapter canvasses the existing conceptual rationales for the unwilling or unable test and discusses the plusses and minuses of each approach. This chapter then articulates a new conceptual justification, one that is arguably implicit in many articulations of the unwilling or unable test. This conceptual justification states that even if the intervening state violates the sovereignty of the territorial state, the territorial state is “estopped” from objecting to the violation, on account of the territorial state’s complicity or powerlessness with regard to the non-state state actor. It is asserted that this notion of “sovereignty estoppel” captures, in a nuanced way, the international community’s discomfort with these interventions but also the community’s all-things-considered judgment that such actions may be necessary in some contexts.

Article 51’s Reporting Requirement as a Space for Legal Argument and Factfulness

Uncertainties continue to exist as regards the function, contents, and application of the proportionality principle in the context of the right to self-defense. Similarly, it has been suggested that the principle of necessity gains new meaning in the context of non-state actor self-defense as it provides the basis for an unwilling/unable test, but this test remains disputed. While appreciating the wealth of scholarly writings on these ad bellum principles, this chapter aims to reflect on how states can be pulled into the conversation more clearly with a view to clarifying the law. It explores how more space can be created for legal argument and factfulness in use of force discourse by states. Specifically, the chapter seeks to enhance necessity and proportionality discourse through the strengthening of U.N. Security Council reporting structures. Building on ideas to “proceduralize Article 51,” the chapter suggests the development of reporting requirements for any use of force on the basis of a duty to explain. It also proposes a more comprehensive architectural rethinking of the institutional environment in which adherence to and application of the necessity and proportionality principles are tested and contested.

The Quest for an Internal Jus Ad Bellum: International Law’s Missing Link, Mere Distraction, or Pandora’s Box?

In recent years, international law’s supposed “neutrality” toward rebellion has been challenged by authors who have argued for an ad bellum ban on the first resort to hostilities or, conversely, for an exceptional and conditional right of organized armed resistance for non-state actors only. This chapter revisits the proposed “internal jus ad bellum” models. The first section examines whether an additional ad bellum layer is needed in order to restrain government recourse to force against rebels and shares some thoughts as to whether adding an ad bellum prohibition on government recourse to force against rebels is moreover feasible. The second section deals with internal use of force against the state and scrutinizes the proposal to create a broader right of organized armed resistance at the ad bellum level. The concluding section explores the links between the proposed internal jus ad bellum, on the one hand, and the concept of recognition of belligerency and third-state intervention in non-international armed conflicts (NIACs), on the other hand.