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On Human Shields and Excuses
By Antti Kauppinen

The recent war in Gaza has stimulated a lot of popular discussion about the moral implications of the use of so-called ‘human shields’, non-combatants who are in close proximity to combatants, either voluntarily or involuntarily. Much of this discussion has been very simplistic and transparently rhetorical. Nevertheless, there are interesting ethical issues arising in the context of asymmetrical warfare that we should be able to examine at a degree of abstraction from the contested facts.

I should perhaps note that I have never read anything on just war theory, so I apologize in advance if what I say below is old hat; all I know is that the points I make are not taken into account by popular commentary, even by leading philosophers like Michael Walzer. I hope writing in relative ignorance is okay for a blog post – my first ever, incidentally.

Let us begin with a reconstruction of what seems to be the underlying argument of many commentators. I will label it the Double Effect Argument, since it makes crucial reference to the Doctrine of Double Effect:

1. The Principle of Non-Combatant Immunity (NCI): Even in a just war, it is not morally acceptable to aim to kill or harm non-combatants.
2. The Principle of Combatant Non-Immunity (CNI): Killing, and aiming to kill, enemy combatants when (it is highly likely to be) necessary to achieve morally justified war aims is morally justified.
3. If enemy combatants intentionally place themselves among non-combatants (human shields) in order to abuse the Principle of Non-Combatant Immunity, they become morally responsible for any damage to non-combatants.
4. Thus, the presence of human shields makes no difference to the responsibilities of the party pursuing legitimate military goals: it continues to be justified in aiming to kill enemy combatants, even if it has the known side effect of killing and maiming human shields. This relies on what I will call the Narrow Doctrine of Double Effect (NDDE): it is permissible to knowingly cause harm as a side effect when it cannot be avoided while pursuing justified goals in the circumstances (which in this case are created by the enemy, not the agent). Bluntly: it is permissible to ignore harm to non-combatants, when a) it is not part of one’s aim or means and b) the enemy is responsible for placing the non-combatants in harm’s way.

Since I want to discuss the moral principles at a certain level of abstraction, I will talk about country A and militant group B below. I will assume that A has jus ad bellum against B; if it doesn’t, I take it jus in bello, justice in the conduct of war, is impossible or of little relevance. If B has a widespread practice of using human shields, the Double Effect Argument legitimizes quite a lot of damage to civilians of B by A. I’ll make four preliminary points, and then argue that the Double Effect Argument is far too permissive. The burden for justifying harm to human shields is much heavier than many commentators realize. Excuses for killing civilians do not come cheap.

1) High burden of justification
First, I want to emphasize that we are talking about terrible things here. We are talking about children burned to death, mothers losing both legs, fathers blinded, as a consequence of A’s action. We cannot be glib about justification on this issue.

2) The difference between hostages and human shields
Whether human shields are in the vicinity of fighters voluntarily or not, there is an important difference between them and hostages: human shields are at no risk from the fighters. Even if they are compelled at gunpoint to stay, it is not the case that were A’s troops to leave, the human shields would be at risk of being hurt. There are no demands to be met for their safe release, as in the case of hostages. This means that there is no need for A to interfere in the interest of the human shields, unlike in a hostage situation.

3) Rarity
Note that civilians are used as human shields only if the combatants’ intention is to abuse NCI. If there are combatants in the vicinity of civilians, because it is the only shelter available in the battle zone, or because they are defending that very area, the civilians are not used as human shields. Theoretically, the difference is clear, and comes out counterfactually: in the latter cases, the combatants would prefer the non-combatants to be able to leave the battle zone. Practically, this is naturally difficult to tell, though as a rule of thumb, if A’s own military action prevents B’s non-combatants from leaving, they are probably not used as human shields. In actual fact, the use of human shields is likely to be very rare.

4) Necessity
Note that CNI, as I have defined it, is very strict, as I think it should be. It does not legitimize killing enemy soldiers on leave, for example (unless that is necessary to achieve legitimate military goals, which is highly unlikely). It should certainly be brought to bear in all strictness to human shields cases. The stereotypical situation is basically this: B’s fighters are firing at A’s soldiers from among B’s non-combatants. We are assuming that A’s soldiers are on a legitimate mission. We may even assume that the mission is precisely to kill B’s fighters. Still, there is an important question of timing: is it really absolutely necessary to kill the fighters in question now, when they are among civilians? Must the military advance made this way, and must it made right now in order to reach the just war goals? Is it possible to open a passage for the non-combatants to leave? (If the fighters lay down their arms and mingle with the non-combatants, that is itself progress toward the just war goals.) Consequently, in every human shields situation, there is a weighty moral reason to wait as long as possible and offer a chance for the human shields to leave – in other words, to transform it into a non-human shields situation. It is morally wrong to kill combatants when it is not necessary to achieve just war aims, and it is doubly so to risk the lives of civilians when killing the combatants during the time they are in their vicinity is not absolutely necessary. (Obeying this principle may make wars last longer; this is itself a bad thing, but we must remember that a war in which jus in bello principles are strictly followed is a very different kind of war from the ones that we have actually seen.)

5) Intention, side effect, and alternative means
Suppose killing the B fighters among human shields right now is a military necessity. A is then faced with a choice of means. If A is a military superpower, it will have a large range of means at its disposal: snipers, mortars, artillery, missiles, bombs. It is here that the narrow doctrine of double effect is revealed as inadequate. For it is silent on the nature of the means involved. Compare the following scenarios:

Minimum: Two of B’s fighters are firing from a UN building with three hundred refugees they are using as human shields. It is a legitimate war aim of A to kill as many of B’s fighters as possible. To kill them, explosives must be used; heavy enemy fire prevents the use of snipers. The fighters are both in the east end of the building, as the live feed from A’s pilotless drone reveals. The commander in charge of A’s operation offers the non-combatants a safe passage to a Red Cross refugee camp outside the war zone, but they do not avail of the opportunity. A’s computer-and-satellite-guided artillery is very accurate (and the most accurate weapon available), and the commander waits for it to be available rather than using alternative means like missiles or mortars (which are far more inaccurate). The commander chooses the smallest available explosive payload, say 2 kg, and a shell is fired at the UN building. The two fighters die, as do four civilians closest to them, while 12 are injured.

Maximum: The same as above, except the commander chooses the most deadly explosives available in order to make sure that the two fighters are killed. The 100 kg shell is fired and obliterates the target. The two fighters die, along with 43 non-combatants and over 200 seriously injured.

The moral I’d like to draw from these two cases is the following. First, in terms of the narrow doctrine of double effect, these two cases are morally equivalent. In both cases, A’s intention is to kill the fighters, not any civilians. Killing civilians is not a means to any end of A’s, but risking it cannot be avoided in the circumstances (for which A is not morally responsible, under our assumptions). Hence, if the end is justified, A’s commander is equally justified in Minimum and Maximum. The narrow doctrine of double effect thus gives no guidance on the means one may use to kill one’s enemies.

Second, there is a significant moral difference between Minimum and Maximum. Indeed, I believe Maximum rises to the level of war crime, in spite of all the unlikely justificatory conditions (legitimate aim, military necessity, opportunity to leave, etc.) being in place. It is not just that the commander chooses the means knowing that there will be civilian casualties as a side effect. He chooses a means that ensures there will be maximal civilian casualties. This is a choice for which the enemy combatants can be held in no way morally responsible, even if they otherwise bear a significant responsibility for placing the human shields at risk. The magnitude of the risk, so to speak, is in the hands of A’s commander, not in the hands of B’s fighters. And it seems self-evident to me that A’s commander should, in these circumstances, minimize the risk to non-combatants. Otherwise A’s commander will intentionally place non-combatants at higher risk than necessary to achieve legitimate war aims. And when that risk is high enough, the moral difference between aiming at the death of civilians and causing their death as a side effect evaporates.

This suggests the following principle to replace NCI:

The Principle of Non-Combatant Protection (NCP)
Jus in bello requires aiming to protect the non-combatant population from war damage as far as possible within the pursuit of morally legitimate military goals.

NCP is stronger than NCI, since it requires not only the absence of intention to harm but also the presence of intention to protect. A commander who obeys NCP will choose the means that is least risky for the non-combatants, even when it makes success in the military goal less likely. (I suppose a weaker principle would suffice to distinguish between Minimum and Maximum, but NCP seems independently plausible.) Gross violations of NCP may be war crimes, even if they obey the letter of NCI.

Third, and relatedly, in these cases, as in most real-life cases, there is a trade-off between risk to own troops and risk to non-combatants. Firing high-caliber weapons from a distance beyond the enemy’s reach minimizes risk to own troops while maximizing the risk to non-combatants. This seems morally unacceptable. In terms of virtue, it is cowardice. It is very difficult to say where the balance lies here, but at the very least, jus in bello, not to mention military virtue, requires that the commander take the risk to non-combatants into account in deliberating how to proceed, not just risk to own troops.

As I said at the beginning, these thoughts are inspired by the conflict in Gaza, and in particular attempts to morally justify the large-scale killing and maiming of civilians that has taken place. I believe the burden of justification is significantly higher than many commentators claim. Whether it is nevertheless met by either side is a factual rather than philosophical question, so there is no point in debating it here. Let me just register my incredulity.


  1. 1. Posted by Dara Conn | January 19, 2009 11:49 pm

    I read this analysis with great interest, and found the line of argument clear and compelling. I have previously found the line that civilian deaths are simply the fault of the enemy (for operating or sheltering among civilians) or of the civilians themselves (for sheltering the enemy) unconvincing and inadequate, but would struggled to articulate why, beyond an emotional aversion to the phenomenon of blaming the victim. Your article provides a welcome clarity around these issues, in part by setting aside larger moral questions such as the justice of the war itself. You make a very good case for the duty of those prosecuting a war to protect non-combatants, and I heartily endorse this principle.

  2. 2. Posted by S. Matthew Liao | January 20, 2009 12:50 am

    Intersting stuff, Antti, and welcome aboard!

    I’m not an expert in this area, but I think that at least Michael Walzer may not disagree with you, since he has argued in Just and Unjust War that the doctrine double effect should be supplemented with what he calls the idea of double intention: combatants are not only to refrain from intending to harm civilians; they are also to take precautions to reduce risk to civilians, even at the expense of increasing risk to themselves. The idea of double intention seems to be similar in spirit to NCP.

  3. 3. Posted by Clayton Littlejohn | January 20, 2009 1:05 am


    I doubt I disagree with you on the important points, but I think with a minor modification to the doctrine of double effect the problems you raise can be mitigated.

    The doctrine as you wrote it:
    it is permissible to knowingly cause harm as a side effect when it cannot be avoided while pursuing justified goals in the circumstances

    Rewrite as:
    it is permissible to knowingly cause a harm as a side effect when it cannot be avoided while pursuing justified goals in the circumstances.

    With DDE reformulated by changing ‘harm’ from a mass noun to count noun, why can’t a defender of DDE now say what you want to say since given the means available in minimum, the harms in maximum are shown not to be necessary for producing the end common to maximum and minimum? In short, you want to say that someone acts wrongly if they carry out the means in Max rather than the means in Min and the DDE reformulated gives us the result and the rationale you seek: the harms in Max are known not to be necessary to produce the desired end and that ensures that the decision to cause those harms cannot be justified.

  4. 4. Posted by Alex Gregory | January 20, 2009 9:08 am

    (I should start by emphasising that I’m making a point in the abstract here, and that its application to the situation in Gaza will depend on many things of which I am too ignorant to comment on.)

    Like Clayton, I’m inclined to think that there are other versions of the DDE that avoid your objection. In particular, you could understand it as the claim that it is less bad to knowingly cause harm as an unavoidable side-effect of the pursuit of just goals than it is to bring about harm in other ways. This is much weaker, but seems to retain the central thought driving the DDE.

    That allows that there is a clear difference between minimum and maximum. It also entails that in some situations, known side-effects might be highly relevant to determining the moral status of an action. But it still retains the central idea that merely foreseen harms are somehow less serious than intended harms.

  5. 5. Posted by Antti Kauppinen | January 20, 2009 3:55 pm

    Thanks, Dara – though it appears I may have been scooped here, at least in part.

    Matthew, I will check out what Walzer says in the book. As I said, I’ve only read his popular essays on various Middle East wars, which definitely bring up human shields in the context of excuse-making. Perhaps his practice doesn’t match his theory.

    In general, I don’t mind reinventing the wheel, especially one that isn’t used much as is. And I guess it’s no surprise that people have made a distinction equivalent to NCI and NCP. But the point I would like to articulate as clearly as possible is that the question about who is responsible for a bad side effect is an ambiguous one. It is possible for one party to be responsible for the existence of a bad side effect, and another party to be responsible for the extent of it. To give it a fancy name, call this the Principle of Divided Responsibility (PDR). I hope it is somewhat more novel – though I wouldn’t be shocked if someone quoted it from Aquinas.

    I suppose PDR is what distinguishes human shields cases from standard double effect scenarios like the Strategic Bomber (bombing a munitions factory while knowing that the children in the next-door kindergarten will die). Someone might argue that while in Strategic Bomber the agent is responsible for minimizing the side effect, this is not the case in human shields scenarios, since the enemy intentionally creates the circumstances where the side effect arises. PDR reveals the flaw in this reasoning. The fact that someone else is responsible for the existence of the side effect doesn’t get the agent off the hook.

    Clayton, tweaking the DDE in something like the clever way you suggest was what I had in mind when I said that a weaker principle than NCP would suffice to distinguish between Max and Min. Having located one plausible principle, I didn’t bother with another. Also, the reason I focused on what I called the narrow DDE is that something like it seems to underlie the actual reasoning of the excusers. And finally, I can now restate the dialectical point a little better: even if a more refined version of DDE (call it DDE+) would suffice to explain the difference between Max and Min, an excuser might argue that DDE+ only applies to cases where nobody has intentionally created the circumstances that give rise to the side effect, whereas in human shields scenarios only NDDE applies, potentially licensing large-scale collateral damage. Armed with PDR, I argue that DDE+ continues to apply in human shields cases as well.

  6. 6. Posted by Nick Shackel | January 21, 2009 2:10 pm

    I think if you’re going to insist on framing this discussion by drawing attention to Gaza then you should have included a great many more relevant facts, such as
    1. that the Bs are the ruling party of government of country C and were voted into power by a democratic election among the Cs,
    2. that the Bs have for many years conducted a war against the As and they have done almost nothing but target A civilians
    3. that surrounding countries D, E and F have, on the creation of A and on a number of occasions since, sought to wipe out A
    4. that countries F, G and H have declared their unity with that intention,
    5. that all of these countries have for 50 years used the As as a scapegoat to distract their populations from the corruption and incompetence of their rulers, most of whom are dictators of one sort or another
    6. that the Cs and many of the other mentioned countries teach their children racist hatred of the As
    7. that in all these countries there is a strong genocidal public discourse aimed at the As
    8. that all these countries have expressed their solidarity with the aims of the Bs and the Cs
    9. that the As are all of religion X and the Bs Cs, Ds, Es, Fs, Gs and Hs are all of the religion Y, that the Bs have in their constituting charter the clause “The Day of Judgment will not come about until Ys fight the Xs (killing the Xs), when the X will hide behind stones and trees. The stones and trees will say O Ys, there is an X behind me, come and kill him.” which is a quotation from the holy books of the Ys
    10. that the Bs have in their constituting charter the genocidal clause”A will exist and will continue to exist until religion Y will obliterate it, just as it obliterated others before it.”

  7. 7. Posted by Antti Kauppinen | January 21, 2009 2:41 pm

    Nick, my post addressed certain kind of moral justification for killing civilians that has been, as a matter of fact, often offered in the context of the conflict in Gaza, most recently. In its crudest forms, it is repeated ad nauseam in some media. Its validity, however, is independent of the particular situation – similar arguments have been made to defend American behaviour, and I wouldn’t be surprised if one found them used to praise Russian moral superiority in the local press. In general, I think we should be suspicious of any purported excuses of the form ‘Yes, what I brought about is terrible, but *I* am not responsible for it’ – even if they do work in certain unusual circumstances.

    The facts you cite, some of which could be disputed, seem in any case relevant to jus ad bellum rather than jus in bello. I don’t think they suffice to mitigate responsibilities toward non-combatants.

  8. 8. Posted by Sanford Levy | January 26, 2009 7:41 pm

    I would like to add a few comments about just war theory and the principle of double effect. First, as often understood, just war theory contains more resources than mentioned so far. First, it generally contains a requirement of proportionality both to go to war and for the conduct of the war. The principle of double effect also generally has such a principle attached. Proportionality is often understood in a more or less utilitarian fashion. Understood in this way, it automatically says we should go for less rather than more death and damage. Second, just war theory often includes a “good hope” clause, that is, a clause that there must be good hope that the war will succeed. Though I know we are trying to talk about Gaza without using the word, it is worth saying that both these points are relevant to the war between Gaza and Israel. But putting aside these points, I would also add that the immunity clause in just war theory is itself somewhat problematical. One of the main problems is exactly who it should cover and just as importantly, why. It is often stated in terms of combatants, and this is sometimes taken to mean that soldiers on leave are immune. But it is not obvious that soldiers at an R and R facility should be immune. Nor is it obvious that soldiers who do not carry guns, say, cooks, are immune. Nor is it obvious that the political leaders, who might have more responsibility (causally and morally) for the war than any one, are immune. Nor is it obvious that a population that actively encourages the war, and might be more responsible (causally and morally) than any soldier, is immune. There is a great deal to be said, and has been said, about just war theory and the principle of double effect. Both have a certain plausibility, but many problems. In my opinion, rather than settling many substantive issues about war, just war theory instead gives us an organized arena that allows us to see where we disagree and agree about various things, such as who counts as immune and what counts as proportionality.

  9. 9. Posted by Nahshon Perez | February 10, 2009 4:00 am

    I want to thanks Antti for this post.
    I have two comments, that perhaps will add to the discussion.
    First, in the scenario above, there are A (attacking forces), B (civilians and ‘human shields’) and C ‘defenders’ who hold the B’s by force. It is assumed that the A’s are under fire from C. And then they need to decide whether to fire back.
    But this lacks one important variable, and that is that during the same time, the C’s (‘defenders’) are attacking D’s – civilians living elsewhere (in the Gaza example, D are the Israeli civilians in Sderot, Ashkelon etc). This I think changes the picture.
    Second, in order to adequately describe the moral dilemma, we need to add some other variables, not in order to say that reality is more complicated, but in order to provide a clearer moral argument.
    Some report on the fighting include roughly the following scenarios:
    A (attacking forces), B (civilians and human shields), C defenders, holding B, attacking A, attacking D – civilians living elsewhere, plus other events and considerations (traps, hidden tunnels, fire from several sources), and lastly, and I think important, incomplete and uncertain information, held by everybody, but relevant to the question in hand, by A: usually with regard to several considerations: whether the C are firing at D ‘now or ‘later’, can A avoid attacking B&C without exposing itself to danger, the number of C’s etc.

    By and large I think these two considerations make the level of legitimate force used by A (in the scenario described) higher than Antti’s original description, but I’m open to further arguments and counter arguments of course.

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