War

If Walzer is right that in war, outside of supreme emergencies, we may
intentionally kill only people who are liable to be killed, and if a
significant proportion of unjust combatants and noncombatants are
responsible to the same degree as one another for unjustified threats,
and if liability is determined by responsibility, then we must decide
between two unpalatable alternatives. If we set a high threshold of
responsibility for liability, to ensure that noncombatants are not
liable to be killed, then we will also exempt many combatants from
liability. In ordinary wars, which do not involve supreme emergencies,
intentionally killing such non-liable combatants would be
impermissible. This moves us towards a kind of pacifism—though
warfare can in principle be justified, it is so hard to fight without
intentionally killing the non-liable that in practice we must be
pacifists (May 2015). But if we set the threshold of responsibility
low, ensuring that all unjust combatants are liable, then many
noncombatants will be liable too, thus rendering them permissible
targets and seriously undermining Discrimination. We are torn between
pacifism on the one hand, and realism on the other. This is the
“responsibility dilemma” for just war theory (Lazar
2010).

4.2 Killing Combatants

Just war theory has meaning only if we can explain why killing some
combatants in war is allowed, but we are not thereby licensed to kill
everyone in the enemy state. Here the competing forces of realism and
pacifism are at their most compelling. It is unsurprising, therefore,
that so much recent work has focused on this topic. We cannot do
justice to all the arguments here, but will instead consider three kinds of
response: all-out revisionist; moderate traditionalist; and all-out
traditionalist.

The first camp faces two challenges: to justify intentionally killing
apparently non-liable unjust combatants; but to do this without
reopening the door to Combatant Equality, or indeed further
undermining Discrimination. Their main move is to argue that, despite
appearances, all and only unjust combatants are in fact liable to be
killed.

McMahan argues that liability to be killed need not, in fact,
presuppose responsibility for an unjustified threat. Instead, unjust
combatants’ responsibility for just combatants’ reasonable
beliefs that they are liable may be enough to ground forfeiture of their rights
(McMahan 2011a). Some argue that combatants’ responsibility for
being in the wrong place at the wrong time is enough (likening them to
voluntary human shields).[22] More radically still, some philosophers abandon the insistence on
individual responsibility, arguing that unjust combatants are
collectively responsible for contributing to unjustified threats, even
if they are individually ineffective (or even counterproductive) (Kamm
2004; Bazargan 2013).

Lazar (forthcoming-a) suggests these arguments are
unpersuasive. Complicity might be relevant to the costs one is
required to bear in war, but most liberals will baulk at the idea of
losing one’s right to life in virtue of things that other people
did. And if combatants can be complicitously liable for what their
comrades-in-arms did, then why shouldn’t noncombatants be
complicitously liable also?

Blameworthy responsibility for other people’s false beliefs does
seem relevant to the ethics of self- and other-defence. That said,
consider an idiot who pretends to be a suicide bomber as a prank, and
is shot by a police officer (Ferzan 2005; McMahan 2005c). Is killing
him objectively permissible? It seems doubtful. The officer’s justified
belief that the prankster posed a threat clearly diminishes the
wrongfulness of killing him (Lazar 2015a). And certainly the
prankster’s fault excuses the officer of any guilt. But killing
the prankster still seems objectively wrong. Even if someone’s
blameworthy responsibility for false beliefs could make killing him
objectively permissible, most philosophers agree that many unjust
combatants are not to blame for the injustice of their wars (McMahan
1994; Lazar 2010). And it is much less plausible that
blameless responsibility for beliefs can make one a permissible
target. Even if it did, this would count in favour of moderate
Combatant Equality, since most just combatants are also blamelessly
responsible for unjust combatants’ reasonable beliefs that they
are liable to be killed.

Moderate traditionalists think we can avoid the realist and pacifist
horns of the responsibility dilemma only by conceding a moderate form
of Combatant Equality. The argument proceeds in three stages. First,
endorse a non-comparative, high threshold of responsibility for
liability, such that most noncombatants in most conflicts are not
responsible enough to be liable to be killed. This helps explain why
killing civilians in war is so hard to justify. Of course, it also
entails that many combatants will be innocent too. The second step,
then, is to defend the principle of Moral Distinction,
according to which killing civilians is worse than killing soldiers.
This is obviously true if the soldiers are liable and the civilians
are not. But the challenge is to show that killing non-liable
civilians is worse than killing non-liable soldiers. If we
can do that, then the permissibility of intentionally killing
non-liable soldiers does not entail that intentionally killing
non-liable noncombatants is permissible. Of course, one might still
argue that, even if Moral Distinction is true, we should endorse
pacifism. But, and this is the third stage, the less seriously
wrongful some act is, the lesser the good that must be realised by
performing that act, for it to be all things considered permissible.
If intentionally killing innocent combatants is not the worst kind of
killing one can do, then the good that must be realised for it to be
all things considered permissible is less than is the case for, for
example, intentionally killing innocent civilians, which philosophers
tend to think can be permissible only in a supreme emergency. This
could mean that intentionally killing innocent soldiers is permissible
even in the ordinary circumstances of war.

Warfare can be justified, then, by a combination of liability and
lesser evil grounds. Some unjust combatants lose their rights not to
be killed. Others’ rights can be overridden without that
implying that unjust noncombatants’ rights may be overridden
too. We can reject the pacifist horn of the responsibility dilemma.
But a moderate Combatant Equality is likely to be true: since killing
innocent combatants is not the worst kind of killing, it is
correspondingly easier for unjust combatants to justify using lethal
force (at least against just combatants). This increases the range of
cases in which they can satisfy Discrimination, Proportionality, and
Necessity, and so fight permissibly.

Much hangs, then, on the arguments for Moral Distinction. Some focus
on why killing innocent noncombatants is especially wrongful; others
on why killing innocent combatants is not so bad. This section
considers the second kind of argument, returning to the first in the
next section.

The revisionists’ arguments mentioned above might not ground
liability, but do perhaps justify some reason to prefer
harming combatants. Combatants can better avoid harm than
noncombatants. Combatants surely do have somewhat greater
responsibilities to bear costs to avert the wrongful actions of their
comrades-in-arms than do noncombatants. And the readiness of most
combatants to fight—regardless of whether their cause is
just—likely means that even just combatants have somewhat
muddied status relative to noncombatants. They conform to their
opponents’ rights only by accident. They have weaker grounds for
complaint when they are wrongfully killed than do noncombatants, who
more robustly respect the rights of others (on robustness and respect,
see Pettit 2015).

Additionally, when combatants kill other combatants, they typically
believe that they are doing so permissibly. Most often they believe
that their cause is just, and that this is a legitimate means to bring
it about. But, insofar as they are lawful combatants, they will also
believe that international law constrains their actions, so that by
fighting in accordance with it they are acting permissibly. Lazar
(2015c) argues that killing people when you know that doing so is
objectively wrong is more seriously objectionable than doing so when
you reasonably believe that you are acting permissibly.

The consent-based argument for Combatant Equality fails because of its
empirical, not its normative premise. If combatants in fact waived
their rights not to be killed by their adversaries, even when fighting
a just war, then that would clearly affect their adversaries’
reasons for action, reducing the wrongfulness of killing anyone who
had waived that right. The problem is that they have not waived their
rights not to be killed. However, they often do offer a more limited
implicit waiver of their rights. The purpose of having armed forces,
and the intention of many who serve in them, is to protect civilians
from the predations of war. This means both countering threats to and
drawing fire away from them. Combatants interpose themselves between
the enemy and their civilian compatriots, and fight on their
compatriots’ behalf. If they abide by the laws of war, they
clearly distinguish themselves from the civilian population, wearing a
uniform and carrying their weapons openly. They implicitly say to
their adversaries: “you ought to put down your weapons. But if
you are going to fight, then fight us”. This
constitutes a limited waiver of their rights against harm. Like a full
waiver, it alters the reasons confronting their
adversaries—under these circumstances, other things equal it is
worse to kill the noncombatants. Of course, in most cases unjust
combatants ought simply to stop fighting. But this conditional waiver
of their opponents’ rights means that, if they are not going to
put down arms, they do better to target combatants than
noncombatants.

Of course, one might think that in virtue of their altruistic
self-sacrifice, just combatants are actually the least
deserving of the harms of war (Tadros 2014). But, first, warfare is
not a means for ensuring that people get their just deserts. More
importantly, given that their altruism is specifically intended to
draw fire away from their compatriot noncombatants, it would be
perverse to treat this as a reason to do precisely what they are
trying to prevent.

These arguments and others suggest that killing innocent combatants is
not the worst kind of killing one can do. It might therefore be all
things considered permissible in the ordinary circumstances of war,
provided enough good is achieved thereby. If unjust combatants attack
only just combatants, and if they achieve some valuable objective by
doing so—defence of their comrades, their co-citizens, or their
territory—they therefore might fight permissibly, even though
they violate the just combatants’ rights (Kamm 2004; Hurka 2005;
Kamm 2005; Steinhoff 2008; Lazar 2013). At least, it is more plausible
that they can fight permissibly than if we regarded every just
combatant’s death as equivalent to the worst kind of murder.
This does not vindicate Combatant Equality—it simply shows that,
more often than one might think, unjust combatants can fight
permissibly. Add to that the fact that all wars are morally
heterogeneous, involving just and unjust phases (Bazargan 2013), and
we quickly see that even if Combatant Equality in the laws of war
lacks fundamental moral foundations, it is a sensible approximation of
the truth.

Some philosophers, however, seek a more robust defence of Combatant
Equality. The three most prominent lines are institutionalist. A
contractualist argument (Benbaji 2008, 2011) starts by observing that
states (and their populations) need disciplined armies for the
purposes of national defence. If soldiers always had to decide for
themselves whether a particular war was just, many states could not
raise armies when they need to. They would be unable to deter
aggression. All states, and all people, benefit from an arrangement
whereby individual combatants waive their rights not to be killed by
one another—allowing them to obey their state’s commands
without second-guessing every deployment. Combatants tacitly consent
to waive their rights in this way, given common knowledge that
fighting in accordance with the laws of war involves such a waiver.
Moreover, their assent is “morally effective” because it
is consistent with a fair and optimal contract among states.

International law does appear to change the moral standing of
combatants. If you join the armed forces of a state, you know that, at
international law, you thereby become a legitimate target in armed
conflict. This has to be relevant to the wrongfulness of harming you,
even if you are fighting for a just cause. But Benbaji’s
argument is more ambitious than this. He thinks that soldiers waive
their rights not to be killed by one another—not the limited,
conditional waiver described above, but an outright waiver, that
absolves their adversaries of any wrongdoing (though it does not so
absolve their military and political leaders).

The first problem with this proposal is that it rests on contentious
empirical speculation about whether soldiers in fact consent in this
way. But setting that aside, second, it is radically statist, implying
that international law simply doesn’t apply to asymmetric
conflicts between states and non-state actors, since the latter are
not part of the appropriate conventions. This gives international law
shallow foundations, which fail to support the visceral outrage that
breaches of international law typically evoke. It also suggests that
states that either don’t ratify major articles of international
law, or that withdraw from agreements, can escape its strictures. This
seems mistaken. Third, we typically regard waivers of fundamental
rights as reversible when new information comes to light. Why
shouldn’t just combatants be allowed to withdraw their
rights-waiver when they are fighting a just war? Many regard the right
to life as inalienable; even if we deny this, we must surely doubt
whether you can alienate it once and for all, under conditions of
inadequate information. Additionally, suppose that you want to join
the armed forces only to fight a specific just war (McMahan 2011b).
Why should you waive your rights against harm in this case, given that
you plan only to fight now? Fourth, and most seriously, even if
Benbaji’s argument explained why killing combatants in war is
permissible regardless of the cause you are serving, it cannot explain
why unintentionally killing noncombatants as a side-effect of
one’s actions is permissible. By joining the armed forces of
their state, soldiers at least do something that implies
their consent to the regime of international law that structures that
role. But noncombatants do not consent to this regime. Soldiers
fighting for unjust causes will inevitably kill many innocent
civilians. If those deaths cannot be rendered proportionate, then
Combatant Equality does not hold.

The second institutionalist argument starts from the belief that we
have a duty to obey the law of our legitimate state. This gives unjust
combatants, ordered to fight an unjust war, some reason to obey those
orders. We can ground this in different ways. Estlund (2007) argues
that the duty to obey orders derives from the epistemic authority of
the state—it is more likely than an individual soldier to know
whether this war is just (see Renzo 2013 for criticism); Cheyney Ryan
(2011) emphasizes the democratic source of the state’s
authority, as well as the crucial importance of maintaining civilian
control of the military. These are genuine moral
reasons that should weigh in soldiers’ deliberations. But are
they really weighty enough to ground Combatant Equality? It seems doubtful.
They cannot systematically override unjust combatants’
obligations not to kill innocent people. This point stands regardless
of whether these reasons weigh in the balance, or are exclusionary
reasons that block others from being considered (Raz 1985). The rights
of innocent people not to be killed are the weightiest, most
fundamental rights around. For some other reason to outweigh them, or
exclude them from deliberation, it would have to be extremely
powerful. Combatants’ obligations to obey orders simply are not
weighty enough—as everyone recognises with respect to obedience
to unlawful in bello commands (McMahan 2009: 66ff).

Like the first argument, the third institutionalist argument grounds
Combatant Equality in its long-term results. But instead of focusing
on states’ ability to defend themselves, it emphasizes the
importance of limiting the horrors of war, given that we know that people
deceive themselves about the justice of their cause (Shue 2008, 2010;
Dill and Shue 2012; Shue 2013; Waldron 2016). Since combatants and
their leaders almost always believe themselves to be in the right, any
injunction to unjust combatants to lay down their arms would simply be
ignored, while any additional permissions to harm noncombatants would
be abused by both sides. In almost all wars, it is sufficient
to achieve military victory that you target only combatants. If doing
this will minimize wrongful deaths in the long run, we should enjoin
that all sides, regardless of their aims, respect Discrimination.
Additionally, while it is extremely difficult to secure international
agreement even about what in fact constitutes a just cause for war
(witness the controversy over the Rome statute on crimes of aggression, which took many years of negotiation before diplomats agreed an uneasy compromise), the traditionalist principles
of jus in bello already have broad international support.
They are hard-won concessions that we should abandon only if we are
sure that the new regime will be an improvement (Roberts 2008).

Although this argument is plausible, it doesn’t address the same
question as the act-focused arguments that preceded it. One thing we
can ask is: given a particular situation, what ought we to do? How
ought soldiers to act in Afghanistan, or Mali, or Syria, or Somalia?
And when we ask this question, we shouldn’t start by assuming
that we or they will obviously fail to comply with any exacting moral
standards that we might propose (Lazar 2012a; Lazar and Valentini
forthcoming). When considering our own actions, and those of people over whom
we have influence, we should select from all the available options,
not rule some out because we know ourselves to be too immoral to take
them. When designing institutions and laws, on the other hand, of
course we should think about how people are likely to respond to them.
We need to answer both kinds of questions: what really ought
I to do? And what should the laws be, given my and others’
predictable frailty?

A moderate Combatant Equality, then, is the likely consequence of
avoiding the pacifist horn of the responsibility dilemma. To show that
killing in war is permissible, we need to show that intentionally
killing innocent combatants is not as seriously wrongful as
intentionally killing innocent noncombatants. And if killing innocent
combatants is not the worst kind of killing, it can more plausibly be
justified by the goods achieved in ordinary wars, outside of supreme
emergencies. On this view, contrary to the views of both Walzer and
his critics, much of the intended killing in justified wars is
permissible not because the targets are liable to be killed, but
because infringing their rights is a permissible lesser evil. But this
principle applies regardless of whether you are on the just or the
unjust side. This in turn increases the range of cases in which
combatants fighting on the unjust side will be able to fight
permissibly: instead of needing to achieve some good comparable to
averting a supreme emergency in order to justify infringing the rights
of just combatants, they need only achieve more prosaic kinds of
goods, since these are not the worst kinds of rights infringements. So
unjust combatants’ associative duties to protect one another and
their compatriots, their duties to obey their legitimate governments,
and other such considerations, can sometimes make intentionally
killing just combatants a permissible lesser evil, and unintentionally
killing noncombatants proportionate. This means that the existing laws
of war are a closer approximation of combatants’ true moral
obligations than many revisionists think. Nonetheless, much of the
killing done by unjust combatants in war is still objectively
wrong.

4.3 Sparing Civilians

The middle path in just war theory depends on showing that killing
civilians is worse than killing soldiers. This section discusses
arguments to explain why killing civilians is distinctly
objectionable. We discuss the significance of intentional
killing when considering proportionality, below.

These arguments are discussed at great length in Lazar (2015c), and
are presented only briefly here. They rest on a key point: Moral
Distinction says that killing civilians is worse than killing
soldiers. It does not say that killing civilians is worse
than killing soldiers, other things equal. Lazar
holds that stronger principle but does not think that the intrinsic
differences between killing civilians and killing soldiers—the
properties that are necessarily instantiated in those two
kinds of killings—are weighty enough to provide Moral
Distinction with the kind of normative force needed to protect
noncombatants in war. That protection depends on mobilising multiple
foundations for Moral Distinction, which include many properties that
are contingently but consistently instantiated in acts that
kill civilians and kill soldiers, which make killing civilians worse.
We cannot ground Moral Distinction in any one of these properties
alone, since each is susceptible to counterexamples. But when they are
all taken together, they justify a relatively sharp line between
harming noncombatants and harming combatants. There are, of course,
hard cases, but these must be decided by appealing to the salient
underlying properties rather than to the mere fact of membership in
one group or the other.

First, at least deliberately killing civilians in war usually fails
even the most relaxed interpretation of the necessity constraint. This
is not always true—killing is necessary if it is effective at
achieving your objective, and no other effective options are
available. Killing civilians sometimes meets this description. It is
often effective: the blockade of Germany helped end the first world
war, though it may have caused as many as half a million civilian
deaths; Russian targeting of civilians in Chechnya reduced Russian
combatant casualties (Lyall 2009); Taliban anti-civilian tactics have
been effective in Afghanistan. And these attacks are often the last
recourse of groups at war (Valentino 2004); when all other options
have failed or become too costly, targeting civilians is relatively
easy to do. Indeed, as recent terrorist attacks have shown (Mumbai and
Paris, for example), fewer than ten motivated gunmen with basic
weaponry can bring the world’s most vibrant cities screeching to
a halt. So, killing civilians can satisfy the necessity
constraint. Nonetheless, attacks on civilians are often wholly wanton,
and there is a special contempt expressed in killing innocent people
either wantonly or for its own sake. At least if you have
some strategic goal in sight, you might believe that
something is at stake that outweighs the innocent lives taken. Those
who kill civilians pointlessly express their total disregard for their
victims in doing so.

Second, even when killing civilians is effective, it is usually so
opportunistically (Quinn 1989; Frowe 2008; Quong 2009; Tadros
2011). That is, the civilians’ suffering is used as a means to
compel their compatriots and their leaders to end their war. Sieges
and aerial bombardments of civilian population centres seek to break
the will of the population and of their government. Combatants, by
contrast, are almost always killed eliminatively—their
deaths are not used to derive a benefit that could not be had without
using them in this way; instead they are killed to solve a problem
that they themselves pose. This too seems relevant to the relative
wrongfulness of these kinds of attacks. Of course, at the strategic
level every death is intended as a message to the enemy leadership,
that the costs of continuing to fight outweigh the benefits. But at
the tactical level, where the actual killing takes place, soldiers
typically kill soldiers eliminatively, while they kill civilians
opportunistically. If this difference is morally important, as many
think, and if acts that kill civilians are opportunistic much more
often than are acts that kill soldiers, then acts that kill civilians
are, in general, worse than acts that kill soldiers. This lends
further support to Moral Distinction.

Third, as already noted above, the agent’s beliefs can affect
the objective seriousness of her act of killing. Killing someone when
you have solid grounds to think that doing so is objectively
permissible wrongs that person less seriously than when your epistemic
basis for harming them is weaker. More precisely, killing an innocent
person is more seriously wrongful the more reason the killer had to
believe that she was not liable to be killed (Lazar 2015a).

Last, in ordinary thinking about the morality of war, the two
properties most commonly cited to explain the distinctive wrongfulness
of harming civilians, after their innocence, are their vulnerability
and their defencelessness. Lazar (2015c) suspects that the duties to
protect the vulnerable and not to harm the defenceless are almost as
basic as the duty not to harm the innocent. (Note that these duties
apply only when their object is morally innocent.) Obviously, on any
plausible analysis, civilians are more vulnerable and defenceless than
soldiers, so if killing innocent people who are more vulnerable and
defenceless is worse than killing those who are less so, then killing
civilians is worse than killing soldiers.

Undoubtedly soldiers are also often vulnerable too—one thinks of
the “Highway of Death”, in Iraq 1991, when American forces
destroyed multiple armoured divisions of the Iraqi army, which were
completely unprotected (many of the personnel in those divisions
escaped into the desert). But this example just shows that killing
soldiers, when they are vulnerable and defenceless, is harder to
justify than when they are not. Provided the empirical claim that
soldiers are less vulnerable and defenceless than civilians is true,
this simply supports the case for Moral Distinction.

4.4 Proportionality

Holding the principle of Moral Distinction allows one to escape the
realist and pacifist horns of the responsibility dilemma, while still
giving responsibility its due. Even revisionists who deny moderate
Combatant Equality could endorse Moral Distinction, and thereby
retain the very plausible insight that it is worse to kill just
noncombatants than to kill just combatants. And, if they are to
account for most people’s considered judgements about war, even
pacifists need some account of why killing civilians is worse than
killing soldiers.

However, Moral Distinction is not Discrimination. It is a comparative
claim, and it says nothing about intentions. Discrimination, by
contrast, prohibits intentionally attacking noncombatants, except in
supreme emergencies. It is the counterpart of Proportionality, which
places a much weaker bar on unintentionally killing noncombatants.
Only a terrible crisis could make it permissible to intentionally
attack noncombatants. But the ordinary goods achieved in individual
battles can justify unintentional killing. What justifies this radical
distinction?

This is one of the oldest questions in normative ethics (though for
the recent debate, see Quinn 1989; Rickless 1997; McIntyre 2001;
Delaney 2006; Thomson 2008; Tadros 2015). On most accounts, those who
intend harm to their victims show them a more objectionable kind of disrespect
than those who unavoidably harm them as a side-effect. Perhaps the
best case for the significance of intentions is, first, in a general
argument that mental states are relevant to objective permissibility
(Christopher 1998; see also Tadros 2011). And second, we need a rich
and unified theoretical account of the specific mental states that
matter in this way, into which intentions fit. It may be that the
special prohibition of intentional attacks on civilians overstates the
moral truth. Intentions do matter. Other things equal, intentional
killings are worse than unintended killings (though some unintended
killings that are wholly negligent or indifferent to the victim are
nearly as bad as intentional killings). But the difference between
them is not categorical. It cannot sustain the contrast between a
near-absolute prohibition on one hand, and a sweeping permission on
the other.

Of course, this is precisely the kind of nuance that would be
disastrous if implemented in international law or if internalized as a
norm by combatants. Weighing lives in war is informationally
incredibly demanding. Soldiers need a principle they can apply.
Discrimination is that principle. It is not merely a rule of
thumb, since it entails something that is morally
grounded—killing civilians is worse than killing soldiers. But
it is also a rule of thumb, because it draws a starker
contrast between intended and unintended killing than is intrinsically
morally justified.

As already noted, proportionality and necessity contain within them
almost every other question in the ethics of war; we now consider two
further points.

First, proportionality in international law is markedly different from
the version of the principle that first-order moral theory supports.
At law, an act of war is proportionate insofar as the harm to
civilians is not excessive in relation to the concrete and direct
military advantage realized thereby. As noted above, in first-order
moral terms, this is unintelligible. But there might be a better
institutional argument for this neutral conception of proportionality.
Proportionality calculations involve many substantive value
judgements—for example, about the significance of moral status,
intentions, risk, vulnerability, defencelessness, and so on. These are
all highly controversial topics. Reasonable disagreement abounds. Many
liberals think that coercive laws should be justified in terms that
others can reasonably accept, rather than depending on controversial
elements of one’s overarching moral theory (Rawls 1996: 217).
The law of armed conflict is coercive; violation constitutes a war
crime, for which one can be punished. Of course, a more complex law
would not be justiciable, but we also have principled grounds for not
basing international law on controversial contemporary disputes in
just war theory. Perhaps the current standard can be endorsed from
within a wider range of overarching moral theories than could anything
closer to the truth.

Second, setting aside the law and focusing again on morality, many
think that responsibility is crucial to thinking about
proportionality, in the following way. Suppose the Free Syrian Army
(FSA) launches an assault on Raqqa, stronghold of ISIL. They predict
that they will cause a number of civilian casualties in their assault,
but that this is only because ISIL has chosen to operate from within a
civilian area, forcing people to be “involuntary human
shields”. Some think that ISIL’s responsibility for
putting those civilians at risk allows the FSA to give those
civilians’ lives less weight in their deliberations than would
be appropriate if ISIL had not used them as human shields (Walzer
2009; Keinon 2014).

But one could also consider the following: Even if ISIL is primarily
at fault for using civilians as cover, why should this mean that those
civilians enjoy weaker protections against being harmed? We typically
think that one should only lose or forfeit one’s rights through
one’s own actions. But on this argument, civilians
enjoy weaker protections against being killed through no fault or
choice of their own. Some might think that more permissive standards
apply for involuntary human shields because of the additional value of
deterring people from taking advantage of morality in this kind of way
(Smilansky 2010; Keinon 2014). But that argument seems oddly circular:
we punish people for taking advantage of our moral restraint by not
showing moral restraint. What’s more, this changes the act from
one that foreseeably kills civilians as an unavoidable side-effect of
countering the military threat to one that kills those civilians as a
means to deter future abuses. This instrumentalizes them in a way that
makes harming them still harder to justify.

4.5 Necessity

The foregoing considerations are all also relevant to necessity. They
allow us to weigh the harms at stake, so that we can determine whether
the morally weighted harm inflicted can be reduced at a reasonable
cost to the agents. The basic structure of necessity is the same
in bello as it is ad bellum, though obviously the
same differences in substance arise as for proportionality. Some
reasons apply only to in bello necessity judgements, not to
ad bellum ones, because they are conditional on the
background assumption that the war as a whole will continue. This
means that we cannot reach judgements of the necessity of the war as a
whole by simply aggregating our judgements about the individual
actions that together constitute the war.

For example, in bello one of the central questions when
applying the necessity principle is: how much risk to our own troops
are we required to bear in order to minimize harms to the innocent?
Some option can be necessary simply in virtue of the fact that it
saves some of our combatants’ lives. Ad bellum,
evaluating the war as a whole, we must of course consider the risk to
our own combatants. But we do so in a different way—we ask
whether the goods achieved by the war as a whole will justify putting
our combatants at risk. We don’t then count among the goods
achieved by the war the fact that multiple actions within the war will
save the lives of individual combatants. We cannot count averting
threats that will arise only if we decide to go to war among the goods
that justify the decision to go to war.

This relates directly to the largely ignored requirement in
international law that combatants must

take all feasible precautions in the choice of means and methods of
attack with a view to avoiding, and in any event to minimizing,
incidental loss of civilian life, injury to civilians and damage to
civilian objects. (Geneva Convention, Article 57, 2(a)(ii))

This has deep moral foundations: combatants in war are morally
required to reduce the risk to innocents until doing so
further would involve an unreasonably high cost to them, which they
cannot be required to bear. Working out when that point is reached
involves thinking through: soldiers’ role-obligations to assume
risks; the difference between doing harm to civilians and allowing it
to happen to oneself or one’s comrades-in-arms; the importance
of associative duties to protect one’s comrades; and all the
considerations already adduced in favour of Moral Distinction. This
calculus is very hard to perform. My own view is that combatants ought
to give significant priority to the lives of civilians (Walzer and
Margalit 2009; McMahan 2010b). This is in stark contrast to existing
practice (Luban 2014).

Much recent work has used either traditionalist or revisionist just
war theory to consider new developments in the practice of warfare,
especially the use of drones, and the possible development of
autonomous weapons systems. Others have focused on the ethics of
non-state conflicts, and asymmetric wars. Very few contemporary wars
fit the nation-state model of the mid-twentieth century, and conflicts
involving non-state actors raise interesting questions for legitimate
authority and the principle of Discrimination in particular (Parry
2016). A third development, provoked by the terrible failure to plan
ahead in Iraq and Afghanistan, is the wave of reflection on the
aftermath of war. This topic, jus post bellum, is addressed
separately.

As to the philosophical foundations of just war theory: the
traditionalist and revisionist positions are now well staked out. But
the really interesting questions that remain to be answered should be
approached without thinking in terms of that split. Most notably, political philosophers may have something more to contribute
to the just war theory debate. It would be interesting, too, to think
with a more open mind about the institutions of international law
(nobody has yet vindicated the claim that the law of armed conflict
has authority, for example), and also about the role of the military
within nation-states, outside of wartime (Ryan 2016).

The collective dimensions of warfare could be more fully
explored. Several philosophers have considered how soldiers “act
together” when they fight (Zohar 1993; Kutz 2005; Bazargan
2013). But few have reflected on whether group agency is present and
morally relevant in war. And yet it is superficially very natural to
discuss wars in these terms, especially in evaluating the war as a
whole. When the British parliament debated in late 2015 whether to
join the war against ISIL in Syria and Iraq, undoubtedly each MP was
thinking also about what she ought to do. But most of them
were asking themselves what the United Kingdom ought to
do. This group action might be wholly reducible to the individual
actions of which it is composed. But this still raises interesting
questions: in particular, how should I justify my actions, as an
individual who is acting on behalf of the group? Must I appeal only to
reasons that apply to me? Or can I act on reasons that apply to the
group’s other members or to the group as a whole? And can I
assess the permissibility of my actions without assessing the group
action of which they are part? Despite the prominence of collectivist
thinking in war, discussion of war’s group morality is very much
in its infancy.