Minimal responsibility threateners (MRTs) are epistemically justified but mistaken in thinking that imposing a non-negligible risk on others is permissible. On standard accounts, an MRT forfeits her right not to be defensively killed. I propose an alternative account: an MRT is liable only to the degree of harm equivalent to what she risks causing multiplied by her degree of responsibility. Harm imposed on the MRT above that amount is justified as a lesser evil, relative to allowing the MRT to kill her victim. This hybrid account, which generalizes to those are who are more than minimally responsible, has considerable advantages. (1994): 74-94, p. 91. 2 This is Derek Parfit's terminology. He says an act "would be wrong in the fact-relative sense just when this act would be wrong in the ordinary sense if we knew all of the morally relevant facts". And an act "would be wrong in the evidence-relative sense just when this act would be wrong in the ordinary sense if we believed what the available evidence gives us decisive reasons to believe, and these beliefs were true". See: Derek Parfit, On What Matters (Oxford: Oxford University Press, 2011), 150. Some might find this distinction unhelpful, since it adverts to a third, 'ordinary' sense of wrong. Others might think that there is no purely fact-relative sense of 'wrong' --that instead such acts, like tornadoes and diseases, are merely unfortunate. Given either worry, we can replace the claim that what an MRT does is wrong in the fact-relative sense with the claim that what she does has bad consequences, with no redeeming good consequences.

Jeff McMahan has argued against the moral equivalence of combatants (MEC) by developing a liability-based account of killing in warfare. On this account, a combatant is morally liable to be killed only if doing so is an effective means of reducing or eliminating an unjust threat to which that combatant is contributing. Since combatants fighting for a just cause generally do not contribute to unjust threats, they are not morally liable to be killed; thus MEC is mistaken. The problem, however, is that many unjust combatants contribute very little to the war in which they participate-often no more than the typical civilian. Thus either the typical civilian is morally liable to be killed, or many unjust combatants are not morally liable to be killed. That is, the liability based account seems to force us to choose between a version of pacifism, and total war. Seth Lazar has called this ''The Responsibility Dilemma''. But I will argue that we can salvage a liabilitybased account of war-one which rejects MEC-by grounding the moral liability of unjust combatants not only in their individual contributions but also in their com-plicit participation in that war. On this view, all enlistees, regardless of the degree to which they contribute to an unjust war, are complicitously liable to be killed if it is necessary to avert an unjust threat posed by their side. This collectivized liability based account I develop avoids the Responsibility Dilemma unlike individualized liability-based accounts of the sort developed by McMahan.

Some collateral harms affecting enemy civilians during a war are agentially mediated -for example, the US-led invasion of Iraq in 2003 sparked an insurgency which killed thousands of Iraqi civilians. I call these 'collaterally enabled harms.' Intuitively, we ought to discount the weight that these harms receive in the 'costs' column of our ad bellum proportionality calculation. But I argue that an occupying military force with de facto political authority has a special obligation to provide minimal protection to the civilian population. As a result, when an occupying military force collaterally enables a harm affecting the civilian population, the weight that the harm ought to receive in the ad bellum proportionality calculation is unaffected by the fact that the harm is agentially mediatedit ought to be weighed at least as heavily as those harms that the occupying force collaterally commits directly. As a result, satisfying the ad bellum proportionality constraint in wars of territorial occupation is more difficult than it has been thought.

The principle of noncombatant immunity prohibits warring parties from intentionally targeting noncombatants. I explicate the moral version of this view and its criticisms by reductive individualists; they argue that certain civilians on the unjust side are morally liable to be lethally targeted to forestall substantial contributions to that war. I then argue that reductivists are mistaken in thinking that causally contributing to an unjust war is a necessary condition for moral liability. Certain noncontributing civilians-notably, war-profiteerscan be morally liable to be lethally targeted. Thus, the principle of noncombatant immunity is mistaken as a moral (though not necessarily as a legal) doctrine, not just because some civilians contribute substantially, but because some unjustly enriched civilians culpably fail to discharge their restitutionary duties to those whose victimization made the unjust enrichment possible. Consequently, the moral criterion for lethal liability in war is even broader than reductive individualists have argued.

The moral equality of combatants (MEC) is a doctrine about the principles governing the conduct of combatants in a war (where “conduct” is taken to include not only how combatants are permitted to fight, but whether they are permitted to fight). According to MEC, the principles governing the conduct of combatants in a war do not depend on what side in the war the combatants are fighting on. Thus, if MEC is correct, then for any side in a war, the principles governing the conduct of the combatants do not depend on whether that side is fighting a just war. Consequently, if it is permissible to fight in a just war, combatants do no wrong by fighting in an unjust war. The most distinguished supporter of this application of MEC is Michael Walzer. In his influential book Just and Unjust Wars (2000), Walzer argues that the responsibility for waging an unjust war rests with military and civilian leaders – not with combatants who typically have no control over the decisions made by their leaders, and who typically are subjected to deception, indoctrination, and coercion by the state. Thus, in a war with a just and unjust side, the combatants fighting on the unjust side (unjust combatants) are typically no less morally innocent than those fighting on the just side (just combatants). Walzer argues that since both just and unjust combatants are morally innocent (unless they commit war crimes) the principles governing combat ought not to distinguish just combatants from unjust combatants.