Lecture I

Lecture I explores cases in which moral and legal rules governing an activity apply even to those who are not permitted to engage in it, focusing on the striking case of the rules governing the conduct of war, which apply even to an aggressor’s combatants, who should not be fighting at all. This structure is morally intelligible once the rules are understood to introduce novel prohibitions rather than new permissions. This issue is examined through what was traditionally the most significant restriction on the conduct of war, the prohibition of perfidy, that is, false negotiation or surrender. Perfidy has received relatively little recent attention, but it is systematically important because of its moral structure: it appropriates the possibility of peace as a weapon of war. As such, it leaves no way out of war. This distinctive wartime wrong is the same whether committed by an aggressor or a defender.

The Battle of the Lexicons

This commentary on Arthur Ripstein’s Tanner Lectures raises doubts about his main claims about ius ad bellum and ius in bello. It argues, among other things, that his views about “settlement by force” entail pacifism, that the moral justification for defensive war applies equally to a limited range of wars of aggression, that some wars of humanitarian intervention are morally justified even if they constitute aggression, and that Ripstein’s reasons for claiming that aggression is always morally wrong do not support a legal prohibition of aggression but instead presuppose such a prohibition. In opposition to Ripstein’s views about ius in bello, the author argues that it is mistaken to suppose that being “part of the war” is the criterion for determining who may be attacked, that the relevant distinction is not between combatants and civilians but between those who are morally liable to attack (which can include some civilians) and those who are not, and that the rules of ius in bello are not prohibitions that can be obeyed equally by both just and unjust combatants.

The Problem of Perfidy and the Failure of Forms

This commentary on Arthur Ripstein’s Tanner Lectures takes up several principal concerns with Ripstein’s powerful argument. First, the author suggests that Ripstein understates the tension, verging on contradiction, of the ius ad bellum and the ius in bello, where the former (in modern thought) treats wars as a great evil to be avoided at nearly all costs, while the second treats war as a legitimate form of interpersonal conflict. Second, the author queries whether Ripstein’s focus in Lecture I on the wrong of perfidy causes him to place too much emphasis on the specific value of a negotiated peace, as opposed to further, intrinsic concerns with the breach of trust and lack of honor. And third, the author questions whether formal features of an aggressor’s intention can make any difference to the (im)permissibility of killing civilians. Last, the author strongly endorses Ripstein’s conception of the ethics of war as grounded in politics, not individual, interpersonal morality.

War’s Distinctive Immorality

This response takes up some of the central themes raised by the commentators, working from the most general to the most specific. Ripstein responds to the suggestion that category-based reasoning is empty or irrelevant, and then turns his attention to clarifying the difference between prohibitions and permissions, considering the additional in bello rules of necessity and proportionality. Next, he addresses questions about why defensive war is the basic case for thinking about whether someone is part of the war, and the specific prohibition of perfidy. Only then does he take up two topics mentioned only in passing in the lectures: the role of international institutions, and the relevance of a state-focused account of war in the context of non-international armed conflict.

Lecture II

Lecture II extends the peace-centered account from the first lecture to the distinction between combatants and civilians, showing how it is already implicit in the wrongfulness of perfidy: perfidy is wrong because it is inconsistent with exiting the conditions of war; targeting civilians or civilian property or infrastructure is wrong because it makes everyone and everything part of the war. In so doing, Lecture II redeems the familiar idea, now thought by many to be naïve, that it is a special wrong for combatants to attack civilians because they are not part of the war. The second part of the lecture explains why an aggressor’s combatants cannot be punished for their participation in a war of aggression, even though such participation is morally wrong.

Introduction

This book focuses on the central puzzle of how the rules of war regulate the conduct of people already engaged in a prohibited activity—namely, aggressive war. Ripstein’s project is to provide an account of why the laws of war should apply equally to wrongdoers—that is, those who participate in an impermissibly initiated war—and to those who are in the right. The book also includes three comments on Ripstein’s lectures, followed by a reply to the comments. This introduction outlines the primary claims put forward in the lectures, comments, and reply, and it offers some additional points of discussion, including how acknowledging the lawfulness of Security Council-authorized humanitarian intervention can be reconciled with the book’s primary argument.

The Principle of Distinction and the Role of Consent

Arthur Ripstein offers a Kantian response to what he calls “Shawcross’s argument”—the argument that the killing of combatants in war is justifiable only where the war is legal. In doing so, he is seeking to provide a moral justification for what may appear to be an incoherence between the two main pillars of modern law of war: On the one hand, the ius ad bellum provides that states may only lawfully resort to war when they have a just cause. On the other hand, the ius in bello specifies rules governing conduct that apply equally to both sides in a conflict—regardless of whether they are waging a lawful or unlawful war. Hence combatants in an unlawful war are entitled to the same immunities from prosecution as combatants in a lawful one. But how can that possibly be morally just? Shawcross rejects that moral equivalence, comparing combatants in unlawful wars to a “lawless robber band.” In the process, Shawcross—and those sympathetic to his view—threaten to upend the modern law of war. Ripstein comes to international law’s defense, though not in terms most international lawyers would find familiar. Ripstein’s effort to morally ground the international legal rules is admirable. Yet the argument provides a moral foundation for the modern rules of war that is incomplete at best. Moreover, it fails to grapple with the voluntary nature of international law, which allows states to agree to further their long-term best interests even at the price of short-term constraints.