Ethical and Constitutional Foundations

This chapter begins by tracing the historical sources of the principle of proportionality since antiquity. It then presents three possible justifications for this principle. First, the chapter discusses the Just War tradition of proportionality. It then moves on to explain why a utilitarian or rational view of IHL would also support the principle of proportionality. Next, the chapter discusses a justification for the principle of proportionality under the theory of IHL as a mode of societal and political control. The last part of the chapter places the discussion of proportionality in IHL in the wider context of the principle of proportionality as a general principle in constitutional and administrative law.

An Introduction to Proportionality

The first chapter of the book presents the basic definition of the principle of proportionality in International Humanitarian Law (IHL) as well as the reason this book was written—the major problems that currently exist regarding the understanding and application of proportionality. The chapter also explains how proportionality relates to the other primary principles of IHL, especially the principle of distinction and the principle of military necessity. The chapter further presents the basic legal texts in which the principle of proportionality appears. Finally, the chapter details the structure of the book and the different legal issues that will be discussed in this work.

Incidental Harm and the Analysis of Proportionality

The principle of proportionality requires weighing the expected military advantage from an attack against the anticipated harm to civilians and civilian objects. This chapter discusses the civilian side of the proportionality equation. It presents the most comprehensive discussion of this subject in the existing literature. The following issues are scrutinized: the meaning of the term civilian; the kinds of harm that the attacking party should consider (damage to persons and objects, economic harm, damage to the environment); the need to take into account indirect and reverberating effects of the attack; the required certainty in anticipating that the attack’s harm would be inflicted; and finally—what constitutes “excessive” incidental harm. The chapter then discusses how the two sides of the proportionality analysis must be weighed and compared. Is proportionality merely any imbalance between the collateral damage as compared with the military advantage, or is a higher threshold required? From whose viewpoint is proportionality examined and under what standard of examination?

Conclusion—A Way Forward?

In classic wars between two states, the main principle of IHL that protected civilians was the principle of distinction. The parties to the conflict were prohibited from directing their fire at civilians. The principle of proportionality was designed as a supplement to this rule, in order to resolve those relatively rare cases in which the effects of an attack on a military target cannot be separated from the civilian objective....

Strategic and Cultural Considerations

Proportionality requires weighing the concrete and direct military advantage. Should the proportionality of an attack be affected by broader considerations, such as the context of the conflict and its circumstances? More specifically, can cultural or strategic considerations—such as each party’s capabilities, military goals or aims, sensibilities, and vulnerabilities—be weighed as part of the military advantage anticipated from an attack? The argument raised in this chapter is that in principle, states should not be differentiated according to their strategic and cultural sensitivities. However, there are state-specific factors that should be considered in assessing the application of the principle of proportionality. Examples of such factors are the technological abilities, defensive systems, and relative power of the parties to the conflict.

The Vagueness of Proportionality

When considering the term “proportionality,” most people intuitively assume that a quantitative value that can be attached to it. In this chapter, this assumption is questioned. First, the chapter presents empirical evidence that indicates that there is no agreement on a specific numerical formula among IHL experts or military officers. Second, the chapter critically evaluates attempts to create a formula for evaluating proportionality. Third, the chapter discusses the use of “rules of thumb” to reduce the uncertainties of the application of proportionality. We conclude that the principle is inherently vague, and intentionally so. No amount of knowledge or experience can lead to the same results, nor is it the goal of the principle of proportionality to achieve the same results across the board. In this regard, proportionality in IHL is not about numbers so much as it is about ensuring the undertaking of a process that weighs competing interests. The relative weighting to be used in any given case is intentionally left open, beyond the purview of the principle.

Direct Participation in Hostilities and Its Effect on Proportionality

Unlike members of the armed forces and combatants who can be targeted, civilians are protected from direct attack. However, civilians do not always enjoy protection. When civilians take a direct part in the hostilities, such as by taking up arms against the enemy, they lose their civilian protection and can be lawfully targeted. Classifying a civilian who is directly participating in hostilities as such is relevant to proportionality as well as to the principle of distinction, as it changes the proportionality analysis in two complementary ways. First, an attack on a civilian that is taking a direct part in hostilities would arguably augment the expected military advantage of the strike. Second, such civilians do not enjoy protection from attack and are also not considered civilians in the proportionality assessment. This means that classifying civilians as direct participants in hostilities might make an otherwise disproportionate attack proportionate, and vice versa. This chapter explains the concept of direct participation in hostilities, and its relevance to the proportionality analysis.

The Principle of Distinction and Its Relation to Proportionality

Proportionality prohibits causing excessive damage to civilian objects and civilians when attacking a military objective. The question which objects are legitimate military objectives, and which are civilian objects, is therefore of great importance. A broader definition of “military objectives” can be expected to justify greater harm to civilians and civilian objects, whereas a narrower definition would restrain military operations. This is especially true today, when conflicts are increasingly taking place in urban settings, with disturbing consequences for civilians. This chapter discusses how the principle of distinction and indiscriminate attacks, while also addressing the issue of dual-use objectives. The chapter also turns to the protection of cultural property.

Soldiers vs. Civilians

Should the interest of protecting the lives of soldiers be examined as part of the military advantage anticipated from an attack? To what level of risk should parties to an armed conflict expose their soldiers in order to minimize harm to civilians? This dilemma, also known as force protection, has been gaining prominence in legal discourse and military practice as Western societies have become more averse to suffering casualties of members of their own military. The chapter promotes the position that protecting the lives of soldiers should be considered in the proportionality analysis as part of the military advantage. Regarding the weight that should be given to the protection of soldiers’ lives, the chapter differentiates between three types of situations in which different levels of protection should afforded to lives of soldiers: (1) attacks that are preplanned, where the protection of the lives of soldiers should be at the lowest level; (2) situations in which units encounter civilians during an operation, where protection of the lives of soldiers should be at a higher level; and (3) units that find themselves under attack, where the protection of lives of soldiers should be at the highest level.

Judicial Review and Investigations

This chapter focuses on the external review of the application of the principle of proportionality. The chapter first considers judicial review of the application of proportionality. Two kinds of review are compared: the ex ante review applied by courts before an action is taken and the ex post review, including criminal investigations. The authors suggest that both kinds of judicial review are ineffective ways to apply the principle of proportionality. An alternative approach is then considered: creating permanent Humanitarian Law Commissions, with the authority to investigate possible violations of the principle of proportionality. Humanitarian Law Commissions could monitor the propriety of criminal or disciplinary investigations conducted by the military; but, more importantly, they could also engage in policy review—that is, they could review ex post whether a specific policy or operation was conducted in accordance with international law, and issue recommendations for future military actions. Such recommendations may help clarify for the military some of the more complex norms they are required to implement.