In this article we focus on the jus in bello principle of necessity for guiding the use of autonomous weapons systems (AWS). We begin our analysis with an account of the principle of necessity as entailing the requirement of minimal force found in Just War Theory, before highlighting the absence of this principle in existing work on AWS. Overlooking this principle means discounting the obligations that combatants have towards one another in times of war. We argue that the requirement of (...) minimal force is an important requirement for considering ethical uses of force. In particular, we distinguish between lethal and non-lethal purposes of use of force and introduce the prospect of non-lethal AWS before reviewing a number of challenges which AWS pose with respect to their non-lethal use. The challenges arise where AWS generate unpredictable outcomes impinging upon the situational awareness required of combatants to ensure that their actions meet the requirement of minimal force. We conclude with a call for further research on the ethical implications of non-lethal uses of AWS as a necessary contribution for assessing the moral permissibility of AWS. (shrink)

Most of us believe that partiality applies in a broad range of relationships. One relationship on which there is much disagreement is co-nationality. Some writers argue that co-national partiality is not justified in certain cases, like killing in war, since killing in defense of co-nationals is intuitively impermissible in other contexts. I argue that this approach overlooks an important structural feature of partiality—namely, that its scope is sometimes restricted. In this essay, I show how some relationships that generate reasons of (...) partiality are restricted in scope—that is, they generate reasons within particular contexts or with respect to particular goods. I then argue that co-national partiality is scope restricted. I then show how this fact helps proponents of co-national partiality overcome the aforementioned objection to its application in cases like war. (shrink)

Because the poorest people tend to die from easily preventable diseases, addressing poverty is a relatively cheap way to save lives. War, by contrast, is extremely expensive. This article argues that, since states that wage war could alleviate poverty instead, poverty can render war unjust. Two just war theory conditions prove relevant: proportionality and last resort. Proportionality requires that war does not yield excessive costs in relation to the benefits. Standardly, just war theorists count only the direct costs: the death (...) and destruction wrought by war. This article argues that it can sometimes be appropriate to add the opportunity costs of a failure to alleviate poverty. Last resort is the condition that there must be no better alternative means of achieving the same just end for which the war is waged. This article argues that there are some cases in which alleviating poverty may constitute a better alternative. These are cases in which the most fitting description of the just end for war is sufficiently general that poverty alleviation offers a means to pursue it. The idea that poverty can sometimes render war unjust has, to date, been largely overlooked. It is, nevertheless, an idea with profound implications since, once taken seriously, war becomes much harder to justify. Wars that, in every other respect, seem just may prove disproportionate or unnecessary given the alternative of alleviating poverty. (shrink)

A just cause for war is a type of wrong that may make those responsible for it morally liable to military attack as a means of preventing or rectifying it. This claim has implications that conflict with assumptions of the current theory of just war.

According to “epistemic-based contingent pacifism” a) there are virtually no wars which we know to be just, and b) it is morally impermissible to wage a war unless we know that the war is just. Thus it follows that there is no war which we are morally permitted to wage. The first claim (a) seems to follow from widespread disagreement among just war theorists over which wars, historically, have been just. I will argue, however, that a source of our inability (...) to confidently distinguish just from unjust wars lies in how we evaluate “morally heterogeneous” wars—i.e., wars with just and unjust aims. Specifically, the practice of reaching a univocal evaluation of a morally heterogeneous war as a whole by aggregating the evaluations of that war’s just and unjust aims is wrongheaded, because it undermines the action-guiding character of jus ad bellum. We ought instead to adopt what I call the “disaggregate approach” to jus ad bellum, according to which we evaluate the various aims of a war individually, without aggregating them into an evaluation of the war as a whole. Adopting this approach will eliminate a source of our disagreement over which wars have been just, and will ipso fact eliminate a basis for epistemic-based contingent pacifism. (shrink)

Just wars are supposed to be proportional responses to aggression: the costs of war must not greatly exceed the benefits. This proportionality principle raises a corresponding ‘interpretation problem’: what are the costs and benefits of war, how are they to be determined, and a ‘measurement problem’: how are costs and benefits to be balanced? And it raises a problem about scope: how far into the future do the states of affairs to be measured stretch? It is argued here that weapons (...) innovation always introduces costs, and that these costs cannot be determined in advance of going to war. Three examples, the atomic bomb, the AK-47 and the ancient Greek catapult, are given as examples. It is therefore argued that the proportionality principle is inapplicable prospectively. Some replies to the argument are discussed and rejected. Some more general defences of the proportionality principle are considered and also rejected. Finally, the significance of the argument for Just War Theory as a whole is discussed. (shrink)

War should be understood as an actual, intentional and widespread armed conflict between political communities. Thus, fisticuffs between individual persons do not count as a war, nor does a gang fight, nor does a feud on the order of the Hatfields versus the McCoys. War is a phenomenon which occurs only between political communities, defined as those entities which either are states or intend to become states (in order to allow for civil war). Classical war is international war, a war (...) between different states, like the two World Wars. But just as frequent is war within a state between rival groups or communities, like the American Civil War. Certain political pressure groups, like terrorist organizations, might also be considered “political communities,” in that they are associations of people with a political purpose and, indeed, many of them aspire to statehood or to influence the development of statehood in certain lands. (shrink)

This paper argues that certain central tenets of the traditional theory of the just war cannot be correct. It then advances an alternative account grounded in the same considerations of justice that govern self-defense at the individual level. The implications of this account are unorthodox. It implies that, with few exceptions, combatants who fight for an unjust cause act impermissibly when they attack enemy combatants, and that combatants who fight in a just war may, in certain circumstances, legitimately target noncombatants (...) who bear a significant degree of moral responsibility for a wrong, when the prevention or rectification of that wrong constitutes a just cause for war. (shrink)

The traditional theory of the just war comprises two sets of principles, one governing the resort to war ( jus ad bellum) and the other governing the conduct of war ( jus in bello). The two sets of principles are regarded, in Michael Walzer’s words, as “logically independent. It is perfectly possible for a just war to be fought unjustly and for an unjust war to be fought in strict accordance with the rules.”1 Let us say that those who fight (...) in a just war are “just combatants,” while those who fight in a war that is unjust because it lacks a just cause are “unjust combatants.” (A just cause is an aim that can contribute to the justification for war and that may permissibly be pursued by means of war.)2 The most important implication of the idea that jus in bello is independent of jus ad bellum is that.. (shrink)

Which harms and benefits should be viewed as relevant when considering whether to launch cyber-measures? In this article, we consider this question, which matters because it is central to determining whether cyber-measures should be launched. Several just war theorists hold a version of what we call the ‘Restrictive View’, according to which there are restrictions on the sorts of harms and benefits that should be included in proportionality assessments about the justifiability of going to war (whether cyber or kinetic). We (...) discuss two such views – the Just Cause Restrictive View and Rights-based Restrictive View – and find both wanting. By contrast, we defend what we call the ‘Permissive View’. This holds that all potential goods and bads should be included in proportionality decisions about cyber-measures, even those that appear to be trivial, and where the various harms and benefits are given different weights, according to their agent-relative and agent-neutral features. We argue further that accepting the Permissive View has broader implications for the ethical frameworks governing cyberwar, both in terms of whether cyberattack provide just cause for coercive responses, including kinetic warfare and cyber-responses, and whether cyber-measures should be governed by just war theory or a new theory for cyber-operations. (shrink)

The categories of "civilian" or "soldier,” “combatant" or “noncombatant,” are thought to be stable. Yet, the case of the naked soldier taking a bath challenges such stability in a way that illustrates the serious conceptual and normative problems with identifying such social groups.

This paper argues that certain central tenets of the traditional theory of the just war cannot be correct. It then advances an alternative account grounded in the same considerations of justice that govern self-defense at the individual level. The implications of this account are unorthodox. It implies that, with few exceptions, combatants who fight for an unjust cause act impermissibly when they attack enemy combatants, and that combatants who fight in a just war may, in certain circumstances, legitimately target noncombatants (...) who bear a significant degree of moral responsibility for a wrong, when the prevention or rectification of that wrong constitutes a just cause for war. (shrink)

This paper discusses the novel versions of the right intention and proportionality conditions in the ius ad bellum proposed in Chapter 3 of Frances Kamm’s Ethics for Enemies. It argues that Kamm is right to weaken the right intention condition to require, not positively intending a war’s just cause, but only having that cause’s presence be a necessary condition for war, but wrong to place no limits on why one makes a just cause necessary. It then argues that the weakening (...) she proposes of Jeff McMahan’s very strict interpretation of proportionality does not go far enough. She argues that “conditional just aims” such as disarming an aggressor and deterring future aggression can count toward a war’s proportionality only if they will follow from harms needed to achieve the war’s initial just cause but not if they require additional harms. The paper argues that such aims can justify additional harms. (shrink)

Innocence is a notion that can prove controversial. Claims of innocence typically support not imposing burdens on the innocent when their conduct is relevantly unobjectionable. This paper examines innocence in the context of violent conflict between states or groups. Many thinkers about the morality of such violence want to establish a principle that would protect innocent civilians. Yet the common view in just war theory does not affirm the moral innocence of civilians. Similarly, the common view that soldiers have an (...) equal right to kill does not affirm their equal moral culpability. (shrink)

This article is a response to commentaries on my book, Killing in War, by Cécile Fabre, Alex Leveringhaus and Victor Tadros. It discusses the implications of the approach I have defended for the morality of war for such issues as internecine killing in war, humanitarian intervention and the bases of individual liability to attack in war.

In this article, I develop a general explanatory model of the liability and lesser evil justifications of harm. Despite their respective provenance in consequentialist and deontological ethics, both justifications are, at root, rich forms of the proportionality relationship between a shared set of underlying normative variables. The nature of the proportionality relationship, and the conditions under which it operates, differ between the two forms of justification. The article explores these differences in detail and the implications they have for the justification (...) of self-defense and war. (shrink)

According to just war theory, a resort to war is justified only if it satisfies the right intention condition. This article offers a critical examination of this condition, defending the thesis that, despite its venerable history as part of the just war tradition, it ought to be jettisoned. When properly understood, it turns out to be an unnecessary element of jus ad bellum, adding nothing essential to our assessments of the justice of armed conflict.

This article addresses a previously overlooked problem in the ethics of defensive killing. Everyone agrees that defensive killing can only be justified when it is necessary. But necessary for what? That seemingly simple question turns out to be surprisingly difficult to answer. Imagine Attacker is trying to kill Victim, and the only way one could save Victim is by killing Attacker. It would seem that, in such a case, killing is necessary. But now suppose there is some other innocent person, (...) suffering some entirely distinct threat, whose life one could save instead. Is killing still necessary? The seemingly obvious answer is “yes.” Killing is necessary since it is the only means to achieve the goal that stands to justify killing. The problem with this answer is that it presupposes a certain description of that goal as something like “saving Victim’s life” or “saving Victim’s life from Attacker.” Other descriptions are plausible, such as “saving a life.” On that latter description, killing is unnecessary in this case. The problem we are encountering is the problem of finding the right description of the goal of killing. Call this the “description problem.” This article sets out to solve the description problem and arrives at a radical conclusion. In a variety of cases, we should describe the goal of killing in broad terms, without reference to a specific victim or a specific threat. These broad descriptions—such as “saving a life”—make it easier to find relevant alternatives. Killing, it turns out, is much harder to justify than we might otherwise have thought. (shrink)

This paper surveys the most important recent debates within the ethics of war. Sections 2 and 3 examine the principles governing the resort to war (jus ad bellum) and the principles governing conduct in war (jus in bello). In Section 4, we turn to the moral guidelines governing the ending and aftermath of war (jus post bellum). Finally, in Section 5 we look at recent debates on whether the jus ad bellum and the jus in bello can be evaluated independently (...) of each other. (shrink)

War is bad for the environment, yet the environmental ramifications of warfare have not been widely addressed by just war theorists and revisionist philosophers of war. The law and legal scholars have paid more attention to protecting nature during armed conflict. But because the law focuses invariably on rules mitigating the conduct of hostilities rather than on objective justice of cause, environmental jus ad bellum has been explored even less extensively than environmental ethics in war. Setting out with the presumption (...) against the use of force and its exceptions, this article considers whether environmental harm can trigger a new justification for war, at whose behest, and what might be a proportionate response to aggressive or negligent harm to nature. Force is clearly justified against military attacks. Where environmental harm is not caused by military aggression, proportionality points towards a response short of war. Full‐scale warfare will likely be counterproductive in protecting nature. This is less true if war is fought by drones destroying specific targets, or by cyber‐war, or by alternatives (or supplements) to war such as boycotts, ‘lawfare’, and ‘information/media warfare’. Responding in ways that minimize harm to nature also helps demonstrate ‘right intention’. (shrink)

Journal of Political Philosophy, EarlyView.

Do innocent civilians who will be killed in a justified attack on a nearby military target have a right to defend themselves by shooting down the bomber pilot? I argue that they do not, and that Jeff McMahan's view that they do have such a right—that there is a moral equivalence between pilot and civilian—is flawed in much the same way that Michael Walzer's moral equivalence of combatants—a position that McMahan has so persuasively refuted—is flawed.

McMahan challenges the assumption that respect for self-determination requires an almost exceptionless doctrine of nonintervention by first defining the notions of "intervention" and "self-determination," and then analyzing Walzer's doctrine of nonintervention.

If people have a right to rebel against domestic tyranny, wrongful foreign occupation, or colonial rule, then the normative principles commonly invoked to deal with civil conflicts present a problem. While rebels in some cases might justifiably try to secure human rights by resort to violence, the three normative pillars dealing with armed force provide at best only a partial reflection of the ethics of armed revolt. This article argues that the concept of “terrorism” and the ongoing attempt to define (...) it in international law, the laws of war and their application to armed conflict, and the Responsibility to Protect all obscure as much as clarify the problem. Given the prevalence of political oppression and the occurrence of civil conflicts originating in attempts to confront it, there is therefore a pressing need to establish a place for the rights of rebellion in the international normative architecture. (shrink)