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Necessity in Law and Military Doctrine:
Conflicts and Potential Solutions
June 5, 2021
Abstract
One of the central principles of the law of armed combat (LOAC)
is the principle of necessity, which (roughly) maintains that during
the course of military operations one is prohibited from imposing any
harms which are not necessary for securing one’s goals. This principle
has been a foundational concern for the morality of war since (at least)
the time of Augustine, and it is currently encoded in many statements
of international law and contemporary military doctrine. However,
the various statements of necessity in law and doctrine can lead to
prescriptions which conflict with one another. In this essay I present
two types of conflict that are likely to arise due to the various currently
accepted formulations of necessity, and I then present methods for
minimizing these conflicts in the future. Importantly, the solutions I
present are not based upon any amendment of current law or doctrine,
but are rather of a more pragmatic nature, sketching ways in which
conflict can be handled at an operational level.
1
1 Introduction
‘Therefore it ought to be necessity, and not your will, that de-
stroys an enemy who is fighting you.’1
The principle of necessity is a cornerstone of the ethics and laws of war,
and (roughly) maintains that one ought not impose harms that are unneces-
sary or inflict injuries which are superfluous to those required by the exigen-
cies of war. It has been defended since (at least) the time of Augustine, and
though it was initially taken to be a purely moral concern for those engaged in
warfare, it is now encoded into international law and the doctrine of leading
militaries around the world. However, the precise formulations of necessity
which can currently be found in law and doctrine are generally ones which
are constructed with a specific aim in mind (e.g. minimizing harm to civil-
ians, limiting certain weapons, reducing harm to enemy combatants, etc.).
This makes it possible for the various formulations to give rise to normative
verdicts which conflict with one another, despite the fact that these are all
born of statutes rooted in a single underlying moral/philosophical notion of
necessity. Such potential for conflict is alone reason enough to carefully ex-
amine necessity in law and military doctrine, however it is also worth noting
that there is a general lack of appreciation for these conflicts in both the legal
and philosophical literature. This is not due to any oversights or mistakes
in these disciplines, but rather rooted in the fact that the legal scholarship
focuses more on the particular laws themselves, at the cost of overlooking the
moral foundation of those laws (i.e. the moral principle of necessity), and
the philosophical literature is prone to discuss necessity itself either without
relating it back to the laws of war, or only relating it to a single law of war
(thus overlooking any possible conflicts between laws).2
1Augustine (2001). Political Writings. Cambridge University Press, at 217.
2For such examples in the legal scholarship, see Horton, S. (2006). Kriegsraison or
military necessity – the Bush administration’s Wilhelmine attitude towards the conduct of
Page 2
In this paper, I show that current legal and doctrinal statements rooted in
necessity can give rise to conflicting normative assessments, and I present a
way to handle such conflicts. I begin by presenting the moral/philosophical
conception of necessity (Section 2). I then present the statements of ne-
cessity that can be found in currently binding law and in current military
doctrine, highlighting how these statements are derived from the underlying
moral/philosophical notion of necessity (Section 3). With the legal and doc-
trinal statements laid out, I then present a schematic conception of “conflict”,
discuss two general types of conflict that may arise, and explore and assess
various idealized strategies for dealing with said conflicts (Section 4). Hav-
ing found each idealized strategy to be wanting in some respect, I then put
forward two proposals for dealing with conflicts, and apply those proposals
to concrete cases (Section 5). Finally, I briefly conclude (Section 6).
war. Fordham Int’l LJ, 30:576–598; Schmitt, M. N. (2011). Essays on Law and War at the
Fault Lines. T.M.C. Asser Press, Ch. 3; Hill-Cawthorne, L. (2014). The role of necessity
in international humanitarian and human rights law. Israel Law Review, 47:225–252; and
Lawless, R. (2020). Practical and conceptual challenges to doctrinal military necessity.
In Kreß, C. and Lawless, R., editors, Necessity and Proportionality in International Peace
and Security Law. Oxford University Press. For examples in the philosophical scholarship,
see Dill, J. and Shue, H. (2012). Limiting the killing in war: Military necessity and the St.
Petersburg assumption. Ethics & International Affairs, 26(3):311–333, (which looks only
at the 1868 St. Petersburg Declaration); Lazar, S. (2012). Necessity in self-defense and
war. Philosophy & Public Affairs, 40(1):3–44, (which looks only at Additional Protocol
I, Art. 57); or Hurka, T. (2008). Proportionality and necessity. In May, L., editor, War:
Essays in Political Philosophy, pages 127–144. Cambridge University Press; or Mayer, C.
(2013). Minimizing harm to combatants: Nonlethal weapons, combatants’ rights, and state
responsibility. In Allhoff, F., Evans, N. G., and Henschke, A., editors, Routledge Handbook
of Ethics and War: Just War Theory in the 21st Century, pages 301–311. Routledge,
(which include almost no discussion of the laws of war). Notable examples which provide
more sustained treatment of both law and morality can be found in Garraway, C. (2009).
to kill or not to kill?–dilemmas on the use of force. Journal of Conflict & Security Law,
14(3):499–510; Goodman, R. (2013). The power to kill or capture enemy combatants.
European Journal of International Law, 24(3):819–853; and Ohlin, J. D. and May, L.
(2016). Necessity in International Law. Oxford University Press, but these texts also
do not provide any discussion of potential conflicts between the various laws rooted in
necessity.
Page 3
2 The Moral/Philosophical Conception
In order to be able to later identify the laws and doctrinal points born of the
principle of necessity, let us first examine the current philosophical conception
of necessity as a moral principle. As indicated above, the idea captured in
the principle of necessity, namely that we ought to avoid unnecessary killing
and harming, has a long and proud pedigree. Writing in the 5th century B.C.,
Sun Tzu argued against unnecessary killing, going so far as to say that it is
always better to capture the enemy’s army rather than destroy it.3Roughly
450 years later, Livy, in the same vein, criticized commanders who resorted
to violence and slaughter when they could have instead used diplomacy and
words, and the Indian Laws of Manu provide even more specific restrictions
on the manner in which violence may be employed.4These views are even
more starkly expressed in the writings of Augustine and later Aquinas, in
which it is expressly and unequivocally stated that ‘it ought to be necessity,
and not your will, that destroys an enemy who is fighting you’,5and that
‘if a man uses more violence in self-defense than is necessary, then this will
be unlawful’.6Moving into the Enlightenment and Modern eras, necessity
gained further support, becoming a mainstay of the ethics (and later laws)
of war, and today it is seen as not just a foundational principle, but perhaps
even a decisive one.7
In the remainder of this section, I present the current philosophical un-
derstanding of necessity, in order to provide a foundational conception of the
3Sun Tzu (2015). The Art of War. Chiron Academic Press, at 37 (Ch. 3, §1–2).
4See respectively, Livy (1924). History of Rome, volume III, book V of Loeb Classical
Library. Harvard University Press, at 127, cited in Ohlin and May, supra note 2, at 261;
and Manu (1991). The Laws of Manu. Penguin Books, at 137–138 (Ch. 7, verses 90–93).
5Augustine, supra note 1, at 217.
6Aquinas, T. (2002). Political Writings. Cambridge University Press, at 264.
7See Lazar, S. (2017). War. The Stanford Encyclopedia of Philosophy, especially at
10–15. For a brief but incisive account of the historical development of necessity, see
Ch. 2 of Gardam, J. (2004). Necessity, Proportionality and the Use of Force by States.
Cambridge University Press.
Page 4
principle which can be employed later on. In doing so, I do not present any
novel ideas or arguments, but instead simply briefly recapitulate the most
developed understanding of necessity currently available, namely that pre-
sented by Seth Lazar.8(Readers familiar with the literature on the ethics of
war may thus skip this section.)
AAnalyzing Necessity
Somewhat simplistically, necessity might be understood as demanding that
one only impose harms necessary for the achievement of some military end,
where the term “necessary” is understood in a strict sense. Thus, some
violence or harm would only be deemed permissible (on grounds of necessity)9
if that violence or harm could not possibly be avoided during the course of
securing some military end. However, this view of necessity is liable to be
too restrictive, given that there will rarely (if ever) be violence in war which
is strictly speaking necessary. For any operation or maneuver, there will
usually exist alternatives which might be pursued, and so a strict simplistic
reading of necessity will rule out virtually all violence in war. While such a
sweeping condemnation of wartime operations may be welcomed by some, it
is against the spirit of the ethics of war, which seeks to regulate the conduct
of hostilities, not forbid them. Moreover, such a broad prohibition is unlikely
to be followed by any military, and so it undermines the general strength of
the ethics of war. For these reasons, a simple notion of necessity is untenable.
Instead, what we need is a nuanced formulation of the principle that makes
use of the intuitions driving the simple formulation, while remaining sensitive
to the realities and complexities of moral decision-making in the context of
war and conflict. Seth Lazar provides such a formulation.
8Lazar, supra note 2.
9Though obviously, such violence or harm may be forbidden on other grounds, such
as, e.g. proportionality or discrimination.
Page 5
Lazar explores the underlying assumptions and concerns of necessity by
presenting various formulations of the principle and then pointing out faults
in each formulation, building piecemeal toward his final analysis of necessity.
For brevity, I will skip the details of his arguments, and instead simply present
each of the aspects of necessity he takes to be central in a proper formulation
of the principle.10
Lazar’s first point is that necessity relies on a view of harm that is not
discrete, but rather continuous. Thus, necessity asks not whether or not
some goal can be achieved with or without some particular harm X, but
rather whether or not that goal can be achieved by inflicting less harm than
that imposed by X. Put differently, the mere presence of alternatives does
not impact necessity judgments; only less harmful alternatives do. This is
because necessity is, at core, concerned with minimizing harm during the
course of securing some end.
The second point, and a natural follow-up to the first, concerns which
harms are counted by necessity, and how. With regards to the former ques-
tion, the answer is rather emphatically that all harms count. When under-
taking harmful operations for the achievement of some end, be it political,
military, moral, or otherwise, the amount of violence and suffering we impose
matters regardless of whom we impose it upon. Harms to enemy combatants,
to civilians, and to allies all count when adjudicating necessity. However,
though all harms count, not all harms necessarily count equally. Instead,
there may exist moral (and perhaps legal) reasons to view some harms as
weightier than others. This may be because some individuals have made
themselves liable to being harmed, say, by unjustly attacking innocents. In
that case, some would view these unjust attackers as having forfeited their
10For his full arguments, see Lazar, supra note 2, at 5–14. See also Lazar, S. (2013).
Necessity and non-combatant immunity. Review of International Studies, pages 1–24;
Lazar, S. (2015). Sparing Civilians. Oxford University Press for further explorations of
necessity in the context of the principles of discrimination and non-combatant immunity.
Page 6
rights not to be harmed, thus mitigating the overall wrongness or moral
weightiness of harms imposed on such attackers.11 Some might also view
incidental harm to friendly combatants as less weighty than harm to civil-
ians, given that combatants have often agreed to take on some risks of harm,
whereas civilians have not.12 Now, there is significant reasonable disagree-
ment about these preceding points, and how harms to different groups ought
to be weighed, but one thing which is clear from the scholarship is that it is
not simply harm that matters, but the moral weight of harm, and this fact
should be reflected in our necessity judgments.
The third point has to do with whether necessity is to be understood as
relating to actual harms or only expected harms. Put differently, there is a
question regarding whether the judgments of necessity are to be understood
as fact-relative or evidence-relative ones.13 This point relates to a larger
question of whether our moral theories in general should be fact-relative,
evidence-relative, or some combination of the two. Thankfully though, we
11For discussions of liability and weighting of harms, see, e.g. Fabre, C. (2009). Guns,
food, and liability to attack in war. Ethics, 120(1):36–63; Frowe, H. (2014a). Defensive
Killing. Oxford University Press; Frowe, H. (2014b). Non-combatant liability in war. In
Frowe, H. and Lang, G., editors, How We Fight: Ethics in War, pages 172–188. Oxford
University Press; Lefkowitz, D. (2009). Partiality and weighing harm to non-combatants.
Journal of Moral Philosophy, 6(3):298–316; Kamm, F. M. (2011). Ethics for Enemies:
Terror, Torture, and War. Oxford University Press; McMahan, J. (1994). Self-defense
and the problem of the innocent attacker. Ethics, pages 252–290; McMahan, J. (2005). The
basis of moral liability to defensive killing. Philosophical Issues, 15(1):386–405; McMahan,
J. (2009). Killing in War. Oxford University Press; McPherson, L. K. (2004). Innocence
and responsibility in war. Canadian Journal of Philosophy, 34(4):485–506.
12See, e.g. Haque, A. A. (2017). Law and Morality at War. Oxford University Press;
Walzer, M. (2006). Just and Unjust Wars: A Moral Argument with Historical Illustrations.
Basic Books, 4 edition. Note, though, that this point does not necessarily apply to all
combatants, given that conscripted soldiers may not have voluntarily agreed to take on
any risks at all.
13For a prominent statement of the fact-relative view of the ethics of self-defense and
war, see Thomson, J. J. (1991). Self-defense. Philosophy & Public Affairs, pages 283–310.
For critiques of this view, see Christopher, R. (1998b). Self-defense and defense of others.
Philosophy & Public Affairs, 27(2):123–141; Christopher, R. (1998a). Self-defence and
objectivity: A reply to judith jarvis thomson. Buffalo Criminal Law Review, 1(2):537–574.
Page 7
can withhold judgment on this larger question while also maintaining that
within the context of the ethics of war, the evidence-relative approach is
the one of primary concern. This is rather clear given that in almost all
realistic cases of permissible killing in war, there will in fact exist some non-
lethal or less-lethal option(s) that could have been used. The unfortunate
reality, however, is simply that many of these other options are too difficult
to discern, or are simply unknown to those agents who have to make life and
death decisions under pressing constraints of limited time and information.
It is indeed unfortunate that due to these limitations some individuals are
killed when they could have been less harmfully neutralized, but the soldiers
who use lethal action in good conscience and in accordance with their best
information should not be viewed as having violated the principle of necessity.
And it is highly unlikely that they would in fact be viewed as having violated
necessity,14 further underpinning the view that the principle of necessity in
the ethics of war is to be understood as an evidence-relative principle.15
If, following Lazar, we take the principle of necessity to be evidence-
relative, then this raises the question of what evidence is to be taken into
consideration for necessity judgments. To this point, when determining the
permissibility of some particular act (with regards to necessity), what matters
is the evidence that the acting agent had at the time of acting. Moreover,
on the evidence-relative account, that is all the evidence that counts and
14In fact, most states take the view that ‘commanders and personnel should be evalu-
ated based on information reasonably available at the time of decision’ (US Army Judge
Advocate General (2015b). Operational law handbook. Technical report, International
and Operational Law Department, United States Army, at 12). This is known as the
so-called “Rendulic Rule”.
15Note that none of this should be understood as meaning that necessity cannot be
understood in the fact-relative sense. One could indeed construe necessity in that light,
but this would render impermissible almost all killing in war (and self-defense), because
there will almost always be some possibility to non-lethally avert a threat. Such a radical
form of pacifism may have theoretical and moral merit, but that is a view that is far
outside the normal understanding of necessity within the context of the ethics of war. For
this reason, we move forward with only the evidence-relative view in mind.
Page 8
the only evidence that counts. Thus, if some third-party knows more than
the acting agent does, then this only impacts necessity if that third party
conveys this additional information to the actor, the actor understands what
is conveyed to him or her, and the actor has some reason to give credence
to what the third party is saying. If these elements do not obtain, then the
actor’s evidence is nothing more than what is in his or her head at the time
of acting. Thus, what matters is that the actor chooses a course of action
that would be deemed permissible by a reasonable agent in possession of the
same evidence available to the actor at his/her moment of acting.16
Lazar’s final point concerns the fact that though we can usually opt for
actions that impose more or less harm, these alternatives will rarely have
equal chances of securing the same good, and will sometimes be more likely
to secure goods or will secure different amounts of good with the same prob-
ability. Put differently, it is sometimes possible to increase the level of harm
imposed, but thereby secure far more good (or more certainly secure some
particular good). Because of this, we cannot see necessity as simply requiring
that we look only at options which bring about the same good, or have the
same probability of bringing about a good, and then choose the least harmful
alternative. Rather, ‘[w]e must instead make pairwise comparisons between
alternatives along both axes [harm and good] simultaneously, asking whether
the marginal costs are justified by the marginal benefits.’17
With all of these points in mind, we arrive at the following analysis of
necessity:
Necessity: Some harmful action is permissible with regards to
necessity if an agent, deciding in good faith and with the best
available evidence, judges that there is no less harmful alterna-
16There will plausibly be higher-order duties to make some effort to gain adequate evi-
dence as well, and duties to not be willfully narrow in one’s search for evidence. However,
for the sake of space, such enquiries will have to be set aside for future research.
17Lazar, supra note 2, at 13.
Page 9
tive which could be pursued, such that the marginal (morally
weighted) risks of the pursued action compared with the alterna-
tive are not justified by a marginal increase in (morally weighted)
benefits.18
The essence of this formulation is that necessity demands that agents
make, in good faith, pairwise comparisons between alternative courses of
action, checking whether the changes in harm imposed are justified by coun-
tervailing changes in benefit.
3 Necessity in Law and Military Doctrine
Now that we have a more refined conception of necessity at our disposal, we
can turn to examining the legal and doctrinal statements which are meant to
codify necessity. However, before moving to that task, there are three points
worth briefly stressing.
The first is that within the laws of armed combat (LOAC) and the
doctrines of leading militaries, there are no statements of necessity per se.
Rather, what these documents provide are specifications of the principle as
applied to narrower questions of key import (e.g. based on necessity, what
weapons are permissible, what tactics must be forgone, etc.). This differs
18This analysis very closely follows Lazar’s, with the difference that Lazar’s focuses
on cases of self-defense, where there is a clear defender and attacker, and thereby there
is a rather straightforward sense of which agent has justice on her side. Given this,
Lazar’s exact formulation cannot be directly ported to the principle of necessity in war,
necessitating the changes made in the formulation above. Note also though, that even
though Lazar’s account cannot be directly ported to necessity in war, he goes on to show
how a number of the laws of war fit quite neatly within his analysis. At any rate, in the
arguments to come, Lazar’s analysis will be used only as a reference point to see which
laws of war are inspired by and rooted in necessity, but not to underpin any particular
proposal or interpretation of the laws of war. For Lazar’s statement of necessity, see supra
note 2, at 13, and for his further analysis of necessity and the laws of war, see 23–44,
especially 39–44.
Page 10
from Lazar’s account presented above, which provides a conception of the
core ethical principle of necessity, but does not stipulate what such a concep-
tion might mean in concrete cases.19 Given this, it is important to clearly
state here that Lazar’s account, and the subsequent formulation of necessity
based upon it, is not meant to be seen as a ground for statements of law and
doctrine, nor is it meant to provide support to such statements. Rather, the
above account is only meant to help us to see how certain statements are
rooted in the intuitions and moral values of the principle of necessity.20
The second point concerns a core aspect of the LOAC, namely that the
‘[t]he law relating to the conduct of hostilities is primarily a law of prohibi-
tion: it does not authorize, but prohibits certain things.’21 Thus, the LOAC
stipulates which things are not permitted, but a certain action’s not being
prohibited does not entail its being permitted. Moreover, that the LOAC
is prohibitive law is made clear in law, doctrine, tribunal findings, and the
legal-philosophical discourse.22 What this means for combatants is that the
LOAC provides them with legal immunity from prosecution for acts of killing
within the context of war, but it does not provide them with a license to kill,
nor necessarily with a strong permission to kill.23
The third point concerns the overall conception of necessity under con-
sideration here. Historically, necessity was viewed as both a limiting and
19Lazar does however explore some applications of his principle to broader philosophi-
cal/legal issues of necessity in war. See, for example, 23–38.
20Since the statements of this section are a part of currently binding law, or are part
of current doctrine, we will simply take their grounding and substantiation for granted.
21Additional Protocol I Commentary, paragraph 2238. See also Haque, supra note 12,
at 30–35, as well as the citations therein.
22For example, see respectively, Additional Protocol I, Art. 35–42; paragraph 3 of US
Army (1956). FM 27-10 The Law of Land Warfare. Technical report, United States Army;
the 1948 High Command Case No. 12 United States of America vs. Wilhelm von Leeb et
al.; and Haque, supra note 12.
23Haque, supra note 12, at 23–35. Ohlin and May, supra note 2, presents a competing
view, arguing that the LOAC does provide a license, but their arguments rely on historical
sources of the law, rather than the law itself.
Page 11
a permissive principle,24 and this duality is also present in law and doc-
trine. Thus, there are statements which limit the violence to only that which
is necessary, but there are also principles which allow for derogation from
the general prohibitions “where required by imperative military necessity”.25
Note though, that this does not contradict the second point above; necessity
can indeed be permissive, but the LOAC is still prohibitive law. All that
the permissive statements of necessity maintain is that certain actions are
not contrary to this principle when such actions are dictated by imperative
military necessity. However, such actions may still be impermissible on other
grounds. There are interesting scholarly debates on the interplay between
these seemingly contradictory roles of necessity,26 but for the arguments pre-
sented here, we will for the sake of brevity avoid these, and focus on the
conception of necessity as a limiting principle. This, however, should not
be taken to indicate that the current arguments deny necessity’s role as a
(potentially) permissive principle, nor to advance any exclusively prohibitive
conception of the principle in morality, law, or doctrine.
And now, with the preliminaries dispensed with, we can begin examining
the canonical codifications of necessity in law and military doctrine. For
simplicity of presentation, I will chronologically present the most conspicuous
24See, e.g. Augustine, supra note 1, at 217; De Vitoria, F. (1991). Political Writ-
ings. Cambridge University Press, at 305; Vattel, E. (2008). The Law of Nations
(Droit des gens). Liberty Fund, Inc, at 542. See also Art. 14–16 of the Lieber Code,
available at: https://www.loc.gov/rr/frd/Military_Law/Lieber_Collection/pdf/
Instructions-gov-armies.pdf.
25AP I, Art. 54(5), found in Roberts, A. and Guelff, R., editors (2004). Documents on
the Laws of War. Oxford University Press, 3 edition, at 450–451.
26See, e.g. Carnahan, B. M. (1998). Lincoln, Lieber and the laws of war: the origins
and limits of the principle of military necessity. American Journal of International Law,
92:213–231; Haines, S. (2014). The developing law of weapons: Humanity, distinction and
precautions in attack. In Clapham, A. and Gaeta, P., editors, The Oxford Handbook of
International Law in Armed Conflict, pages 273–295. Oxford University Press; and Kreß,
C. and Lawless, R., editors (2020). Necessity and Proportionality in International Peace
and Security Law. Oxford University Press.
Page 12
legal statutes,27 then the statements in military doctrine, after which I will
provide a loose categorization of these statements into three distinct types
of prohibition.
ANecessity in the Law of Armed Combat
One of the first international legal agreements on the LOAC was the 1868
St. Petersburg Declaration, which banned the use of explosive anti-personnel
bullets.28 This Declaration is notable for not only providing a substantive and
clear prohibition, but for also explicitly basing the prohibition on a succinct
rendering of moral principles. In particular, the Declaration stipulates that:
[C]ivilization should have the effect of alleviating as much as
possible the calamities of war; That the only legitimate object
of which States should endeavor to accomplish during war is to
weaken the military forces of the enemy; That for this purpose
it is sufficient to disable the greatest possible number of men;
That this object would be exceeded by the employment of arms
which uselessly aggravate the sufferings of disabled men or render
their death inevitable; That the employment of such arms would,
therefore, be contrary to the laws of humanity29
In its essence, the 1868 Declaration seeks to ban weapons which impose
more harm than that necessary for military victory, and in particular to ban
weapons which make death inevitable when weapons which disable the enemy
are equally effective. These moral concerns fit squarely within the conception
27Note, however, that I will omit presentation of treaties which have either been sub-
sequently superseded, or have fallen into desuetude.
28The exact prohibition is on explosive bullets under 400 grams in weight. The arbitrary
threshold is intended to permit the use of explosive shells, while outlawing rounds of such
a small size as to only plausibly be used for anti-personnel purposes.
291868 St. Petersburg Declaration, found in Roberts and Guelff, supra note 25, at
54–55.
Page 13
of necessity developed by Lazar, and so we may see the 1868 Declaration as
an embodiment of necessity with regards to choice of weapons.
Following the 1868 Declaration, the 1899 Hague Declaration 3 demanded
that ‘contracting Parties agree to abstain from the use of bullets which ex-
pand or flatten easily in the human body.’30 This Declaration utilizes the
same language and reasoning as the 1868 Declaration, and was indeed seen
by its proponents as nothing more than an extension of the spirit of the
previous agreement.
The next substantial agreements bearing on the discussion here are to
be found in Articles 35 and 57 of the 1977 Additional Protocol I to the
Geneva Conventions (hereafter AP I). Article 35 concerns general methods
and means of warfare, stating that:
1. In any armed conflict, the right of the Parties to the conflict
to choose methods or means of warfare is not unlimited.
2. It is prohibited to employ weapons, projectiles and material
and methods of warfare of a nature to cause superfluous injury
or unnecessary suffering.31
Article 35 is important and far-reaching, given that it not only constitutes
a basic rule of war, but also touches on weapons, ordnance, and tactics of
war. Thus, it places limits on what weapons may be used, how combatants
interact with their enemy, and how combatants interact with civilians and
neutral parties. Its emphasis on those things which ‘cause superfluous injury
or unnecessary suffering’ also makes it indicative of the principle of necessity
developed by Lazar.
301899 Hague Declaration 3, found in Roberts and Guelff, supra note 25, at 64–65.
31AP I, Art. 35(1)–35(2), found in Roberts and Guelff, supra note 25, at 442. This
prohibition is based upon Articles 22 and 23 of the Hague Convention IV (see Roberts
and Guelff, supra note 25, at 77). Note that though the English version of the Hague
Convention IV differs slightly from that of AP I, Art. 35, the original French version –
which is authoritative – uses virtually the same language as that found in AP I, Art. 35.
Page 14
Article 57, on the other hand, is not as broad in its conception as Article
35, and indeed is concerned solely with the protection of civilians. Within
this Article are a number of important protections for civilians, but for our
purposes, the key statements are to be found in 57.2.a.ii and 57.3, which
require that attacking combatant forces
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 objects32
and that
[w]hen a choice is possible between several military objectives
for obtaining a similar military advantage, the objective to be
selected shall be that the attack on which may be expected to
cause the least danger to civilian lives and to civilian objects.33
In essence, Art. 57 demands that combatants plan their attacks ‘with a
view to reducing incidental loss [...] to a minimum.’34 This means, among
other things, that ‘[w]hen a well-placed 500 kg projectile is sufficient to render
a military objective useless, there is no reason to use a 10 ton bomb.’35 More
broadly still, this means that combatants must weigh the options available to
them, and opt for those which, for a given military advantage, are minimally
harmful to civilians. Such a concern is indicative of the moral values captured
in Lazar’s conception of necessity.
32AP I, Art. 57(2)(a)(ii), found in Roberts and Guelff, supra note 25, at 452–453.
Lazar also considers this statement to be an exemplary case of necessity’s demands being
captured in international law. For his discussion, see supra note 2, at 39–44.
33AP I, Art. 57(3), found in Roberts and Guelff, supra note 25, at 453.
34AP I Commentary, paragraph 2203.
35AP I Commentary, paragraph 2200.
Page 15
To sum up, Articles 35 and 57 are pillars of the principle of necessity in
international law, and their role in the LOAC is testified to in their reiteration
in many later treaties and manuals.36 Furthermore, the extensive elaboration
of them within the AP I Commentary provides ample evidence that these
Articles are firmly rooted in the moral principle of necessity which Lazar so
effectively explores. Moreover, these articles do not just embody necessity
in the LOAC, but they also codify it in ways which provide (more) concrete
guidance in situations of war and conflict.
BNecessity in Military Doctrine
The laws of armed combat certainly provide a vital source of guidance when
making ethical decisions in war, but these are not the only source of guidance.
Rather, military doctrine can also bolster and enhance the level of adherence
to deep moral principles, making compliance more regular and possibly even
going beyond the requirements of the letter of the law. At the very least, the
military doctrines of virtually all leading nations will at a minimum provide
restatements and reaffirmations of the LOAC. Such restatements may simply
be quotes of the relevant articles of international law, or they may involve
paraphrases, extensions, and applications of the law to concrete questions of
warfighting.37 For the sake of brevity, in this section I will not explore all
36See, for example, the opening statements of the 1980 Convention on Certain Conven-
tional Weapons, paragraph 46 of the 1994 San Remo Manual, the preamble of the 1997
Ottawa Convention, or Art. 8(b)(xix)–8(b)(xx) of the 1998 Rome Statute.
37The ICRC’s online Customary IHL Database provides an excellent resource for find-
ing military doctrines of all states cross-referenced with the treaty provisions to which
such doctrines relate (see International Committee of the Red Cross (2020a). Cus-
tomary IHL Database. https://ihl-databases.icrc.org/customary-ihl/eng/docs/
home, Accessed: Nov. 9, 2020). For specific statements on doctrine relating to Articles
35 and 57, see respectively International Committee of the Red Cross (2020d). Cus-
tomary IHL Rule 70. https://ihl-databases.icrc.org/customary-ihl/eng/docs/
v2\_cha\_chapter20\_rule70, Accessed: Nov. 9, 2020; and International Committee of
the Red Cross (2020b). Customary IHL Rule 15. https://ihl-databases.icrc.org/
customary-ihl/eng/docs/v2\_cha\_chapter5\_rule15, Accessed: Nov. 9, 2020.
Page 16
the various reaffirmations of the LOAC, but will instead only present key
statements of doctrine which add some point concerning necessity which is
not explicitly present in the above legal statutes. I will also restrict the
discussion to the doctrine of the United States military.38
In U.S. military doctrine, there is first and foremost a clear and explicit
reaffirmation of all of the laws of armed combat, in particular those discussed
above. However, in addition to this, U.S. doctrine makes explicitly clear a
prohibition which is only obliquely captured in AP I, Art. 35, namely that
soldiers are required not just to minimize harms to non-combatants, but
also to minimize the harms they impose on their enemy.39 This duty to
reduce the harm to enemy combatants is stated in documents ranging from
field manuals to training handouts, and its impact can even be seen in some
of the Rules of Engagement (hereafter ROEs) printed on pocket cards and
issued to soldiers entering combat zones.40
In the U.S. Army’s field manual FM 27-10 The Law of Land Warfare, it
is clearly stated that one of the purposes of the law of war is ‘[p]rotecting
38Note that though there are differences between U.S. doctrine and that of other states,
these are in most cases minor. Furthermore, most clear differences relate to rather specific
concerns of treaty and practice, but not to broad principles like those captured in the
statutes discussed above. In short, U.S. doctrine pertaining to issues of ‘unnecessary
suffering and superfluous injury’ does not admit any significant variance to that of other
states.
39Though not made explicit in AP I, Art. 35, the drafters’ concern was not only “with
saving those who did not participate in the hostilities, but also with avoiding any injury or
suffering of the combatants in excess of that necessary to put the enemy hors de combat”
(AP I Commentary, paragraph 1410). Paragraph 1411 of the Commentary goes on to
make clear that
The object of combat is to disarm the enemy. Therefore it is prohibited
to use any means or methods which exceed what is necessary for rendering
the enemy hors de combat. This rule is the corollary to paragraph 1 [of
Article 35], which denies an unlimited right to choose the means to harm
the enemy. Neither the combatants nor the Parties to the conflict are free to
inflict unnecessary damage or injury, or to use violence in an irrational way.
That paragraph concludes that, ‘[a]ll in all, this is the position adopted by the ICRC.’
40See, for example, the ROE cards presented in USJAG, supra note 14, at 106–110.
Page 17
both combatants and noncombatants from unnecessary suffering’,41 and that
this ‘requires that belligerents refrain from employing any kind or degree of
violence which is not actually necessary for military purposes.’42 These words
are reiterated in the United States Judge Advocate General’s Operational
Law Handbook, which further adds that ‘this principle [necessity] requires
military forces to avoid inflicting gratuitous violence on the enemy.’43
The U.S. Marine Corps’ Law of War/Introduction to Rules of Engagement
student handout puts the point even more succinctly, stating that:
Suffering will never be eliminated from war. What we must en-
sure is that our decisions and actions minimize unnecessary suf-
fering to the enemy as well as to any civilians and noncombatants
involved.44
Thus, by Articles 35 and 57 of Additional Protocol I, it is explicitly es-
tablished that soldiers must minimize harm to noncombatants and eschew
any weapons or tactics that by their nature impose unnecessary suffering
or superfluous injury. The points of doctrine presented above add explicitly
that soldiers must also ensure that their actions minimize the suffering they
impose on their enemy as well. This provides an important further restric-
tion, rooted in necessity, which although intended by Art. 35, is not explicit
in its formulation.45
41US Army, supra note 21, at paragraph 2.
42Ibid., at paragraph 3.
43USJAG, supra note 14, at 14 (emphasis in original). See also page 11 for the general
link between necessity and the purposes of the LOAC.
44US Marine Corps Training Command (2015). Law of War/Introduction to Rules of
Engagement. Technical report, United States Marine Corps, at 5.
45See note 39 above.
Page 18
CTypes of Necessity in Law and Doctrine
None of these legal or doctrinal points should be taken to be statements of
necessity as such. Rather, these each provide specifications of what neces-
sity demands with respect to certain narrowly circumscribed questions of
import. These questions of import, and the specifications of necessity meant
to address them, may be categorized into three types: necessity with regards
to weapons, necessity with regards to harm to civilians, and necessity with
regards to harm to the enemy.46
Necessity with regard to weapons is the most straightforward of the three,
and generally rather simple to follow during the course of hostilities. This
type of necessity restricts weapons and ordnance which by their nature im-
pose unnecessary suffering or superfluous injury, and also prohibits using
(otherwise permissible) weapons and ordnance in a way that leads to unnec-
essary suffering or superfluous injury. The former restriction is embodied by
treaties such as the 1868 and 1899 Declarations, both of which prohibit the
use of bullets which are designed to increase the injury and suffering of men
hit by those bullets.47 AP I, Art. 35, on the other hand, makes demands
of both the former and latter kind, due to its more inclusive wording.48 In
general, both types of prohibition will by default be satisfied by most combat-
46There are also legal and doctrinal statements which link necessity to other con-
cerns, such as, for example, the protection of the environment (e.g. AP I, Art. 35(3);
ICRC/UNGA guidelines) or the protection of cultural heritage (e.g. 1954 Hague Conven-
tion and Protocol; AP I, Art. 53). However, for brevity, we will not discuss these. Note
though that these protections could also lead to conflicts of the type to be explored in
sections 4 and 5.
47Notable prohibitions of the same kind are the absolute restrictions against weapons
containing fragments not detectable by X-ray (1980 Convention on Certain Conventional
Weapons, Protocol I) and against blinding lasers (1980 Convention on Certain Conven-
tional Weapons, Protocol IV).
48Prohibitions more exclusively of the latter kind can be found in Protocols II and III
of the 1980 Convention on Certain Conventional Weapons. These protocols do not express
blanket prohibitions on certain weapons, but instead prohibit certain uses of particular
weapons when that usage would be either indiscriminate or be likely to cause dispropor-
tionate or unnecessary suffering.
Page 19
ants, given that prohibited weapons and ordnance simply are not produced
and distributed to the wide majority of combatants, and that weapons and
ordnance which are more likely to be used in ways that are in breach of Art.
35 have additional rules and customary practices to minimize these risks.49
The second type of necessity, namely necessity with regard to harms to
civilians, requires that whenever possible, harms to the civilian population be
minimized. This means that when multiple courses of action are available for
securing some military advantage, commanders are required to utilize that
option which imposes fewer or less severe (risks of) harms to civilians. This
protection is established in customary international law,50 and is extended to
all civilians, regardless of nationality or affiliation to the belligerent parties.
In practice, this type of necessity will be somewhat more demanding for com-
batants and commanders, as it will require them to make nuanced judgments
about the relative risks and benefits of different options. However, though
this can be a difficult task, it is one combatants and commanders undertake
with virtually every choice, as there is nearly always a weighing of risks and
rewards for doing this or that thing in war.
The third type of necessity, necessity with regard to the enemy, requires
that combatants refrain from imposing unnecessary harms or superfluous
injuries on their enemy. More simply, it requires that combatants seek to
49See, for example, the restrictions and practices captured in Protocols II and III of
the 1980 Convention on Certain Conventional Weapons, or Rule 85 of the Customary
IHL database (International Committee of the Red Cross (2020e). Customary IHL Rule
85. https://ihl-databases.icrc.org/customary-ihl/eng/docs/v1\_rul\_rule85,
Accessed: Nov. 9, 2020).
50See IHL Rules 15 and 17 (as well as their groundings in treaty and doctrine),
found respectively at International Committee of the Red Cross (2020b). Custom-
ary IHL Rule 15. https://ihl-databases.icrc.org/customary-ihl/eng/docs/v2\
_cha\_chapter5\_rule15, Accessed: Nov. 9, 2020; and International Committee of the
Red Cross (2020c). Customary IHL Rule 17. https://ihl-databases.icrc.org/
customary-ihl/eng/docs/v1\_rul\_rule17, Accessed: Nov. 9, 2020. See also para-
graphs 2200–2203 of the AP I Commentary for further discussion of the legal protections
of civilians established by AP I, Art. 57.
Page 20
minimize the harms they impose on their enemy.51 And since ‘[t]he object
of combat is to disarm the enemy’, this means that ‘it is prohibited to use
any means or methods which exceed what is necessary for rendering the
enemy hors de combat.’52 This restriction, though sometimes overlooked by
scholars,53 is rooted in both treaty and doctrine, and it is intended to mirror
the protections provided by the principle of necessity with regard to civilians.
Given its structural similarity to the latter, its application in practice is also
subject to the same challenges.
With this loose taxonomy of the the legal and doctrinal guidelines, we
are now in a position to see how these varying requirements might lead to
conflicts when determining what course of action to take during war. The
following sections will be devoted to exploring possible conflicts between these
types of necessity, and showing possible ways to ameliorate or eliminate these
conflicts. For the sake of brevity in what follows, I will refer to the three types
of necessity as, respectively, NEC-Weapons, NEC-Civilian, and NEC-Enemy.
4 Conflicts of Necessity
The underlying moral/philosophical conception of necessity exemplified in
Lazar’s account does not admit the possibility of conflicting duties. That ac-
count (and generally, any philosophical conception of the foundational prin-
ciple of necessity) gives a single standard for determining what courses of
51Recent scholarship exploring this point can be found in Garraway; Goodman; and
Mayer, all cited in supra note 2. Further discussions, which also pay more heed to the legal
landscape, can be found in Blum, G. (2010). The dispensable lives of soldiers. Journal of
Legal Analysis, 2(1):115–170; and Beer, Y. (2015). Humanity considerations cannot reduce
war’s hazards alone: Revitalizing the concept of military necessity. European Journal of
International Law, 26(4):801–828.
52AP I Commentary, paragraph 1411 (emphasis in original).
53Ohlin and May, supra note 2, for example, repeatedly utilizes a notion of necessity
that either ignores or expressly rejects this reading.
Page 21
action are obligatory, permissible, or forbidden (with regards to necessity).54
Likewise, that single standard will not deliver separate obligations that can-
not be jointly fulfilled, nor will it deliver permissions and forbiddances which
conflict.55 However, specifications of what necessity demands with regards to
more specific concerns, like the statements of treaty and doctrine presented
above, can lead to conflict. Thus, the different types of necessity presented in
section C above may lead to conflicting duties in discrete decision scenarios,
or may lead to permissions and prohibitions which directly conflict. In this
section, I present a schematic view of what I mean by “conflict”, after which
I present key types of conflict which are likely to occur during situations of
war and violence. I then examine three idealized strategies for dealing with
these conflicts and provide evaluations of these strategies.
AConflict: A Schema
In what follows, whenever I say “conflict”, which may be thought of as short-
hand for “normative conflict”, I am referring to any situation:
(i) Where the consistent application of one or more legal/doctrinal princi-
ples gives rise to competing normative assessments, such that there are
either multiple obligations issued which cannot all be jointly satisfied,
or there arise permissions and prohibitions which directly conflict;
54It may, however, be all-things-considered obligatory to do something other than what
necessity demands, depending on the relative weights and strengths of different principles
in one’s account of the ethics of war.
55It may, however, deliver multiple permissible courses of action, all of which cannot
be jointly fulfilled. Note also that though necessity will not give rise to conflicting nor-
mative assessments for a single agent, it can lead to normative assessments in separate
agents which conflict with one another. This is because separate agents will have differ-
ent evidence and beliefs, and so an evidence-relative rendering of necessity can generate
distinct obligations or permissions for one agent which conflict with the obligations and
permissions of another agent.
Page 22
(ii) Where these competing assessments cannot be resolved by appealing
to some other code or principle; and
(iii) Where the competing normative assessments are not related to empir-
ical issues, but rather tied to the application of the principle(s) them-
selves.
To go through each of these conditions in turn, (i) is meant to be nothing
more than the basic notion of normative conflict, namely that there are either
multiple normative demands, all of which cannot be jointly satisfied, or there
are permissions and prohibitions which directly conflict with one another.56
Condition (ii) is meant to ensure that we are dealing with genuine nor-
mative conflicts, rather than merely prima facie ones. Thus, sometimes the
application of separate principles might seem to give rise to demands that
compete with one another, but on closer inspection one demand turns out to
be more foundational or to trump the other for some reason.
Condition (iii) is intended to block out conflicts arising from incomplete or
competing information or evidence. Thus, it focuses our notion of conflict on
only those cases where there is (enough) confidence about what facts obtain,
but where competing necessity claims still arise. This is important to include
given that many decisions during wartime may be fraught with uncertainties,
and those uncertainties can often lead to moral or legal judgments that pull in
different directions. In what follows, we will only be concerned with conflicts
56Of the two forms of conflict indicated here, the former represents the classical for-
mulation of normative conflict which can be found in both philosophy and law. See, e.g.
Goble, L. (2013). Prima facie norms, normative conflicts, and dilemmas. In Gabbay,
D., Horty, J., Parent, X., van der Meyden, R., and van der Torre, L., editors, Handbook
of Deontic Logic and Normative Systems, volume 1, pages 241–352. College Publications
London; and Vranes, E. (2006). The definition of ‘norm conflict’ in international law and
legal theory. European Journal of International Law, 17(2):395–418. The latter indicates
a broader notion of conflict, picking out those cases where a set of normative principles
issues one or more permissions, but where acting on those permissions would lead one to
directly violate one or more prohibitions issued by the normative principles.
Page 23
where agents have relative certainty about what necessity demands, permits,
or forbids, but where those demands, permissions, and forbiddances still
allow for conflict.
BTypes of Conflict
Generally speaking, any of the distinct legal or doctrinal statements pre-
sented above can give rise to conflicts with any other distinct legal or doctrinal
statement(s). Moreover, even though all of these statements are rooted in the
underlying moral/philosophical conception of necessity presented in section
2, they may still give rise to conflicting assessments because the statements
are specifications of what necessity requires with regards to some particular
area of interest. Furthermore, any specification of what necessity requires
with regards to some particular area of interest can lead to normative con-
flicts.57
However, though any specification might issue demands at odds with
those of another specification, or give rise to conflicting permissions and
prohibitions, in practice some conflicts will arise more often than others. In
particular, there are two types of conflict which are very likely to occur.
First, conflicts will regularly occur if the objectives and aims of combat or
war are vague or are not conveyed to combatants and commanders. Conflicts
will arise in such situations because, without a war’s discrete aims being made
clear (and also ideally given a ranking of importance), there will be situations
where for a single course of action, necessity with regards to one aim may
issue a permission, but with regards to another aim issue a prohibition. And
these competing normative assessments may be issued without there being a
clear method for deciding which ought be followed or given priority. As an
57For example, the LOAC principles protecting the environment or cultural heritage,
both of which are at least partly formulated in terms rooted in necessity, can lead to
conflicts with one another, or with other legal points rooted in necessity.
Page 24
example, consider the following hypothetical case:
State Aggression: An aggressive state A invades its neighbor V. V
asks the global community for assistance, and a coalition C forms
to aid V. C’s main goal is the eviction of A’s forces from the terri-
tory of V, but C also wishes to punish the pro-war government of
A, and to reduce A’s potential for future aggressive warmaking.
In the course of the war, it happens that a large contingent of A’s
forces are in open retreat, and C can easily destroy all of them
with no risk to itself.58
In this case there is one main goal (evicting A’s forces from the territory
of C) and two secondary goals (punishing A’s government and reducing A’s
ability to wage aggressive war in the future). With regards to the main
goal, NEC-Enemy would demand that the retreating forces be allowed to
safely leave V’s territory, as this would ensure the main goal’s successful
attainment while minimizing harm to the enemy. Put more succinctly, with
regards to the main goal, NEC-Enemy prohibits attacking A’s retreating
forces. With regards to the secondary goal of punishing A’s government,
A’s forces do not necessarily need to be targeted (as there are other less
harmful and potentially more effective ways to punish a state’s government),
and with regards to the secondary goal of reducing A’s future capacity for
aggressive warmaking, A’s equipment and weapons must surely be targeted,
and possibly the soldiers themselves. At any rate, securing the secondary
goals will require the application of some force against the enemy state above
that which is required to attain the main goal. Thus, NEC-Enemy with
regards to the secondary goals will permit some level of violence against A’s
retreating forces.
58The example is presented in a schematic fashion, but it is modeled after the Gulf
War, and is in reference to the so-called “Highway of Death” incident.
Page 25
The problem is that in staying as true to the demands of necessity as pos-
sible, force and harm must be minimized during the attainment of each goal,
but effectively securing certain goals may necessitate imposing more harms,
and as such, necessity may permit and prohibit the same course of action,
depending on which goal is being evaluated. To put it differently, applying
necessity to each goal in isolation will yield demands that compete with one
another, as some level of force will, on grounds of necessity, be permissible
with regards to the secondary goals, but impermissible with regards to the
main goal.59 And without a method for determining the relative importance
of each goal, there will be no principled way to move past the conflict. More
generally, if it is unclear how important each goal is, then C’s forces may
be unsure of how much force to employ, as each goal demands a different
amount of force.60
The second situation in which necessity conflicts are likely to arise is
whenever it is possible to impose less (risk of) harm to one’s enemy by shifting
some (risk of) harm to civilians, and vice versa. The conflict in such instances
arises because NEC-Civilian demands that (risk of) harm to civilians be
minimized, while NEC-Enemy demands that (risk of) harm to one’s enemy
be minimized, but often the minimization of one type of harm comes at
the cost of increasing the other type of harm. Thus, the two specifications
59It would be more accurate to say that, with regards to necessity, harms and violence
are either impermissible or not impermissible. This is because, while there is a logical
equivalence between permissible and not impermissible, there is a distinction in moral and
political philosophy concerning the strength of permission versus lack of forbiddance. See,
e.g. Raz, J. (1975). Permissions and supererogation. American Philosophical Quarterly,
pages 161–168. However, for ease of reading, we simply use permissible.
60Note that the nuances of necessity considerations will be dealt with differently at
each level of command. Thus, high command officers will be concerned with the overall
necessity of larger operations, battalion level officers will be tasked with determining the
minimally harmful way to carry out certain missions, and so on, down to rank-and-file
soldiers whose only concern will be to not use excessive force themselves (but without
thinking about the larger necessity concerns). This point is discussed in more detail in
section 5 below.
Page 26
of what necessity demands can pull in opposite directions. Unfortunately,
these cases are incredibly commonplace in modern war, making this type of
conflict nearly ubiquitous.
As a simple example of this second type of conflict, consider the following
hypothetical case:
Counterinsurgents: Counterinsurgent (COIN) forces need to cross
an urban area in which insurgents are positioned. There is little
military value in engaging the insurgents themselves, but they
will fire on COIN forces, and so must be dealt with in some fash-
ion. The COIN forces have two ways of crossing the area. They
could move slowly, with close air support to help locate the in-
surgents, and fire clean lethal shots to kill the insurgents at no
risk to civilians. Or COIN units could deploy smoke grenades,
and then quickly move through the area while the insurgents are
unable to see them. The smoke will cause irritation to those who
inhale it, but this will be mild, and the use of the smoke grenades
is otherwise permitted by the LOAC.61
In this case, NEC-Civilian (considered in isolation) would demand that
the COIN forces use close air support to locate each insurgent and then fire
live ammunition to directly neutralize the insurgents, thus sparing civilians
from any harm. This method would ensure that civilians suffer no harms
whatsoever, at the cost of ensuring death for each insurgent. On the other
hand, NEC-Enemy (considered in isolation) would demand that COIN forces
use smoke grenades, as this affords the same tactical advantage while drasti-
cally reducing the amount of harm imposed on the enemy, and only imposing
a very minor and passing harm on civilians. One might here object that civil-
ians are afforded extra protections not enjoyed by combatants, and so this
61Note that the example assumes that either option would be effective, and that there
are no further risks or harms than those presented.
Page 27
does not actually pose a conflict (i.e. COIN forces must simply take the
former option). However, the harms presented here are merely illustrative,
and we can easily imagine cases where an extraordinarily minor harm might
be imposed on civilians to allow one to greatly reduce harm to combatants.
So long as combatants enjoy at least some protections from gratuitous harm
– a fact which has been established in section 3 above – it will be possi-
ble for genuine conflicts to arise between the demands of NEC-Civilian and
NEC-Enemy.
CStrategies for Dealing with Conflict
In cases like those presented above, combatants or commanders may be un-
sure of what to do, as the demands of the various types of necessity may
be pulling in different directions. Importantly, in such cases, it is not that
combatants and commanders simply have no idea what to do; rather, they
are presented with situations where they know they are both permitted and
forbidden from doing certain things, or they face situations where they know
that there are multiple things they seemingly ought to do, but they cannot
do all of those things. This thus puts them in a position of uncertainty re-
garding what particular course of action to take. In order to work through
such conflicts, there are many strategies one might pursue, but most strate-
gies can be boiled down to one of three forms (or a combination thereof). In
order to isolate the merits and drawbacks of each strategy, we will examine
highly idealized versions of them.
The first strategy one might employ is to simply place in a hierarchy the
various requirements of necessity specified in treaty and doctrine. In this
way, conflicts would be very straightforwardly handled by simply consult-
ing the hierarchy to see which of the competing demands takes precedence.
In fact, this strategy would not just provide a way to move past conflict,
but would actually eliminate most conflict, as the demands of each type of
necessity would no longer be given equal weight, and some would always
Page 28
trump others.62 This strategy might be motivated on either deontological or
rule-consequentialist grounds,63 and on either basis it can be well-defended.
The benefits of such a strategy are largely practical ones. First of all, it
provides a standard that is easy to understand and employ, meaning that
combatants will have clear guidelines that are useful even in the stress of
combat. Related to this, a simple hierarchy makes it less likely for combat-
ants to make mistakes when applying the rules, something which holds great
weight given how easy it is for value judgments to be biased and warped in
situations as emotionally and mentally taxing as war and combat. Finally,
a hierarchy can also speed the decision-making process, a fact which has
moral value as well, given that more time means more information can be
gathered, making targeting decisions more confident and reducing the risks
of wrongfully harming innocents.
There are three main disadvantages of such a strategy. First, it may (or
perhaps necessarily will) oversimplify the moral complexity of such conflict
cases, glossing over important factors that (arguably ought to) drive what
demands are ultimately issued. Second, if the hierarchy is developed along
rule-consequentialist lines, then even if it provides better guidance in the
majority of cases, it may still sometimes lead to opting for alternatives that
are all-things-considered worse in one instance. This is deeply problematic
because the LOAC is not about distributing goods or benefits, but rather
about limiting harms, and a rule-consequentialist justification is (arguably)
insufficient grounds for imposing all-things-considered greater harm on some
individuals merely because that is generally better than some alternative.
Thirdly, and in the same vein, if the hierarchy is developed along deontologi-
62Though this would eliminate most conflicts, it would not necessarily eliminate all
conflicts, as conflicts arising due to underspecified or vague objectives may still persist.
63For the former, one might argue that certain restrictions are in principle more impor-
tant than others, while for the latter, it might be argued that general adherence to such
a hierarchy leads to better results than if agents decided on their own in each particular
instance.
Page 29
cal lines, it may always provide guidance that is well-rooted in principle, but
it may sometimes lead one to choose alternatives that are far more harmful
than if one deviated from the hierarchy. Thus, a deontologically grounded
hierarchy may lead to a sort of fetishism regarding principles, where more
harm is tolerated for the sake of adhering to the hierarchy, despite the fact
that necessity, which is at the core of all of this, demands that harm be
minimized. Such a state of affairs is arguably problematic.
The second strategy one might pursue is to, when deciding, aim for a
balance between what is demanded by one or another type of necessity, with
decision-makers being permitted general latitude to act as they deem fit
given their evidence at the time. Put more simply, the strategy would be
to demand that combatants and commanders use their (moral and legal)
judgment. This method takes inspiration from the pluralist views of W.D.
Ross64 and the principalist methods of applied biomedical ethics,65 and does
not place any one demand of necessity above any other. Rather, it treats
all demands equally, and expects that decision-makers will use their own
normative judgment to competently determine which should be satisfied in
each instance.
Such a strategy has in its favor that it is similar to what is already the
case for much decision-making in war; combatants and commanders are of-
ten expected to use judgment to determine what to do, weighing competing
moral, legal, and military interests. Moreover, by demanding that judgment
calls be made (and giving some latitude for judgment), the strategy makes
context and information more important, tracking the agent-relative aspects
of the underlying moral/philosophical conception of necessity. These connec-
tions to information and expectations also make this strategy track to how
64See, for example, Ross, W. D. (2007). The Right and the Good. Oxford University
Press.
65See Beauchamp, T. L. and Childress, J. F. (2009). Principles of Biomedical Ethics.
Oxford University Press, 6th edition, especially Part II.
Page 30
necessity is discussed and understood in military tribunals, showing that this
strategy maps well to actual legal practice.66
On the other hand, though more reliance on judgment may be welcomed
by some, there will also likely be some combatants and commanders who
would wish for more guidance on what to do in cases of conflict, and this
strategy does not provide that. Moreover, the lack of guidance may even
lead to abuses, as combatants and commanders who improperly overvalue
their own comrades or civilians (or undervalue enemy combatants and foreign
civilians) would be given more latitude to use their own (flawed) judgment in
conflict cases. A further potential issue is that while it would be excellent to
have combatants and commanders who are competent to make judgments of
the kind required to resolve conflicts, this may be asking too much, as such
competence will likely require extensive training in both moral and legal rea-
soning, something which may be beyond the abilities of regular soldiers, and
even middle- or higher-level commanders. Furthermore, it is likely beyond
the capabilities of states or militaries to even provide the training needed for
soldiers to be able to make such nuanced moral and legal decisions.
The third strategy for dealing with conflicting demands of necessity would
be to, in conflict cases, simply ignore the prescriptions being issued by the
more particular formulations of necessity (e.g. NEC-Civilian and NEC-
Enemy) and instead apply the more foundational moral/philosophical con-
ception. This would avert the conflict entirely – as the particular formula-
tions are what lead to conflict – and ask that combatants and commanders
do what best satisfies the core conception of necessity that inspires and moti-
vates each more particular formulation in law and doctrine. The distinction
between the previous strategy and this one mirrors the distinction between
66See the core tenet of the “Rendulic Rule”, discussed in US Army Judge Advocate
General (2015a). Law of armed conflict deskbook. Technical report, International and
Operational Law Department, United States Army, at 134–135, and in footnote 14 above.
For the trial establishing this rule, see United States of America vs. Wilhelm List, et al.
Page 31
rule-consequentialist and act-consequentialist methodology. One strategy
aims to resolve the conflict by appealing to mid-level principles, which are
themselves based on some underlying principle, whereas the other relies on
the underlying principle itself.
Given its emphasis on the core principle of necessity, this strategy presents
a way to resolve conflicts that is both philosophically and legally defensible.
Moreover, its method for conflict resolution is neither overly simplistic (like
strategy one), nor as susceptible to abuse (like strategy two). By rooting
the resolution of conflict in the core principle of necessity, this strategy also
strengthens the moral and legal primacy of that principle, a fact which could
have positive impact on the nurturing of core tenets of international law (of
which necessity is one).
However, despite these advantages, this third strategy bears its share of
deficits as well. In particular, though the strategy appears strong on paper,
from a practical standpoint, it presents many (possibly irresolvable) diffi-
culties. By asking combatants and commanders to carry out the necessary
calculations to make an all-things-considered necessity judgment, it requires
them to have an extensive amount of evidence about the decision they must
make, as well as the potential outcomes, something which they may simply
not have.67 And even if they do have all of the facts (an assumption that will
rarely, if ever, be true), the necessary moral and legal reasoning needed to
arrive at an all-things-considered judgment is very likely to be beyond that
which combatants and commanders possess; there will need to be (likely ex-
tensive) additional training in order for soldiers to be remotely able to make
67As we are working within an evidence-relative conception of necessity, it is not the
case that combatants and commanders must know the actual facts that obtain in a given
situation. However, in order to carry out any form of necessity calculations, there will
be a minimum of evidence required, otherwise it will be impossible to judge with confi-
dence what options are available, and what outcomes will follow from them. In such an
evidence-poor scenario, combatants and commanders will be forced to go by “gut instinct”,
undermining any idea of applying necessity, and instead putting them back into the realm
of strategy two presented above.
Page 32
such nuanced judgments about moral and legal values. Furthermore, making
such judgments will also invariably be a more involved and time-consuming
process, and time is not always a luxury combatants enjoy, meaning that
sometimes combatants and commanders will end up doing something more
in line with strategy two anyway (e.g. when time runs out, they will just use
their best judgment and ignore the half-finished calculations). These points
show that while the third strategy may hold theoretical strength, it will in
practice be difficult to rely on, as it will not always (or even often) be able
to deliver results in situations of conflict.
5 A Way Forward
The three strategies presented above carry with them serious problems, but
each also holds merit as well. What we therefore need is some method which
can manage to capture the advantages of each strategy while avoiding their
respective pitfalls. In particular, we will need some strategy for dealing with
conflict which is 1) easy to understand and employ, 2) may be employed
quickly and without a high likelihood of errors, 3) allows some room for
judgment on the part of combatants and commanders (without leaving too
much room), and which 4) makes the resolution of conflict sensitive to the
demands of the core principle of necessity (while not requiring that combat-
ants and commanders actually necessarily employ that core principle). As a
separate general constraint, any method for resolving conflict should be built
such that compliance with the method makes combatants and commanders
more likely to act in accordance with morality (and law) than would be the
case were they to follow their own best judgment. This does not mean that
compliance with the method would guarantee that all acts would be in ac-
cordance with morality (or law), but following the method should at least
make combatants and commanders more likely to act in accordance with
these normative sources. Put differently, any method for resolving conflicts
Page 33
should be of service to combatants and commanders, helping them to better
dispense with their obligations than they could without that method.68
In the remainder of this work, I present two distinct proposals for dealing
with the two types of conflict presented in section B.69 To recall, the first
type of conflict is conflict due to the presence of multiple war aims that are
vague or poorly conveyed to combatants. The proposal for dealing with this
type of conflict is to demand that the aims of a war be fully specified, given
relative weights of importance, and adequately conveyed to combatants and
commanders. The second type of conflict is conflict between NEC-Civilian
and NEC-Enemy. The proposal for dealing with this type of conflict is to
develop Rules of Engagement (ROEs) to provide straightforward guidance
when such conflicts arise.
ADefining Operational Goals as a Means to Avoid
NEC Conflicts
Most wars will have some primary aim, most often national self-defense or
defense of some ally’s territorial integrity. However, in addition to this pri-
mary aim, there are often secondary aims as well. These can range from
punishing the enemy government who instigated war to exacting some form
of reparations to crippling the military of the enemy government so they can-
not wage aggressive wars in the future. Importantly, for any distinct goals,
it will almost always be the case that their accomplishment will require dif-
68This is the heart of Admil Haque’s so-called “service view” of the LOAC. For his
fuller treatment, see Haque, supra note 12, at 43–49. For arguments pointing in a similar
direction, see also McMahan, J. (2004). The ethics of killing in war. Ethics, 114(4):693–
733, at 729–733; and McMahan, J. (2008). The morality of war and the law of war. In
Rodin, D. and Shue, H., editors, Just and Unjust Warriors: The Moral and Legal Status
of Soldiers, pages 19–43. Oxford University Press, at 37–41
69Since the aim is to achieve maximal compliance, rather than theoretical elegance,
having a (possibly ad hoc) distinct way to deal with each conflict is preferable, as this
allows each method to be simpler, thereby making it more practically useful.
Page 34
ferent outcomes to be achieved. This in turn means that distinct goals will
necessitate distinct different courses of action be considered, and these dif-
ferent courses of action may require different levels of force and harm to be
brought to bear. And since necessity (and its various specifications in law
and doctrine) allows one to use the necessary level of force, but also demands
a minimization of harm during the securing of any discrete aim, these dif-
ferent aims will lead to permissions and prohibitions which may run against
one another.
Since the root cause of the conflict here has to do with the specification
and weighting of war aims, the first point of the proposal is of a more polit-
ical nature. Namely, the proposal first requires that all war aims be clearly
specified with regards to quantifiable outcomes. Thus, notions like “spread-
ing freedom” ought not be given as war aims, as this is an outcome whose
accomplishment cannot be straightforwardly assessed. Instead, all war aims
should be simple outcomes which higher-level commanders are able to under-
stand and work toward (e.g. driving enemy forces from an invaded nation’s
territory). Secondly, when all war aims have been clearly specified, they
should then be given a ranking of importance. This may be in terms of rela-
tive weights, but for practical reasons should more likely be in terms of some
lexical ordering of goals, as that provides a simpler guide to action which
will be of greater use to commanders and combatants who are determining
how best to follow the LOAC while achieving their objectives.70 Once the
war aims have been specified and given their ranking, it is then crucial that
this information be passed down the chain of command to those who must
70Note that any ranking will represent a particular ordering of the goals at some mo-
ment, but the ordering may change at a later time. Thus, at any given time, there should
exist a clearly demarcated and well-ordered set of goals, but this need not remain static
throughout a conflict. Goals may change, or their relative importance may change, and
there is nothing in the current proposal that prevents either of these from occurring.
Rather, the proposal simply demands that goals be clear and ranked, and that if the goals
or their ordering changes, that such changes are then conveyed to the combatants and
commanders ultimately responsible for securing the goals.
Page 35
make decisions about the war aims. Importantly, it is also necessary that
these overarching war aims (and their relative weights) be diligently consid-
ered when commanders are setting intermediate operational goals, as some
harmful operations may prove necessary for securing a less important goal,
but unnecessary for securing a more important goal, and such would argue
against the execution of those operations. Thus, overarching war aims (and
their weights) should inform the planning of theater level goals, which in turn
should inform smaller-level operational goals, and so on down to platoon- and
squad-level maneuvers. And at each level, the purpose of the operation (with
regards to the goal to which it directly contributes) should be conveyed to
combatants carrying out said operations. It need not be the case that all
levels of command have a full understanding of the larger war aims, but each
level should know how its operations contribute to the (intermediate) goals
directly above it.71 By ensuring that each goal is clear, that the set of goals
is well-ranked, and that those ranked goals factor into lower-level planning,
combatants and commanders will thus be given adequate guidance to pre-
vent them from even entering into situations where conflicts of necessity will
arise.
BApplication of the Proposal
To see how this proposal would function in practice, recall the first example
from section B. In that case, a coalition C was aiding a state V in defending
against an aggressor state A. The coalition C had the main goal of evicting
A’s forces from the territory of V, but also secondary goals of (i) punishing A’s
71The importance of tactical goals and maneuvers being pursued with constant care
as to how they contribute to larger strategic goals is also recognized by military planners
themselves. See, for example, Krulak, C. C. (1999). The strategic corporal: Leadership in
the three block war. Technical report, Center for Army Lessons Learned Fort Leavenworth
Virtual Research Library. For a more general discussion of different levels of planning and
how they relate to necessity, see Bujnoch, L. (2020). Understanding necessity in war and
conflict. PhD thesis, University of Glasgow, Ch. 4, especially at 121-140.
Page 36
government and (ii) reducing A’s potential for future aggressive warmaking.
So there are three goals being pursued, and since one is taken to be “primary”
with two others deemed “secondary”, we can at least already set the primary
goal as lexically prior to the two secondary goals. What this means is that
the planning of operations and setting of intermediate goals will first and
foremost be aimed toward securing the primary goal. This also means that
the demands of necessity relating to the primary goal are the most important
demands. However, there are two secondary goals, and there is no additional
information as to how important they each are with respect to one another.
This means that competing demands of necessity relating to goal (i) or (ii)
will place combatants and commanders in a position where they do not know
which demand to follow.
The first step to remedying this is to clarify exactly what these secondary
goals in fact are. In particular, goal (i), punishing A’s government, needs to
be spelled out in unmistakable and quantifiable terms (goal (ii) is already
stated in clear quantifiable terms). Are the armed forces of C to take the
destruction of A’s military as a “punishment”, or should they destroy the
domestic economy of A, or should they find the political leaders of A and put
them on trial for the crime of aggression? Or is any one of these an acceptable
form of punishment? In order for C’s combatants and commanders to be able
to plan operations which will achieve mission success, they must first know
exactly what constitutes mission success. Knowing this, they will then also
be able to confidently address the demands of necessity when planning their
operations.72 For the sake of argument, let us assume that secondary goal
(i) is specified to mean the capture of A’s leaders for the purposes of trying
them at the International Criminal Court (hereafter ICC). This makes goal
72If multiple outcomes count as “success”, necessity will also be able to help in the
planning process by ruling out certain operations leading to “successful” outcomes be-
cause they necessitate the imposition of more harm than other operations leading to other
“successful” outcomes.
Page 37
(i) tractable, with a clear stipulation of what C’s forces must achieve.
With the secondary goals spelled out in precise quantifiable terms, it then
must be made clear what the relative importance of each goal is. This will
be a political question, and the answer may vary depending on the time and
place, but for the sake of argument, let us simply assume that goal (i) is
determined to be lexically prior to goal (ii), such that it is always more im-
portant to secure (i) than (ii). We might further specify the weights of the
goals by adding that the more fully (i) is achieved, the less important (ii) be-
comes, thus giving an inverse relation between the two. (Such a relationship
would make intuitive sense, as the more strictly the leaders of A are punished
for the crime of aggression, the less important it may be to dismantle A’s
military, as aggressive warmaking will be deterred by the criminal prosecu-
tions of A’s leader(s), negating any need to disarm the state A.) At any rate,
these weights and rankings of the secondary goals provide commanders and
planners with robust guides for how to plan operations that will secure the
aims of the war while remaining as true to the LOAC as possible.
The final step of the proposal is to ensure that the specified goals and their
weights are incorporated into mission planning on all levels. This will both
ensure that each part of the war effort actually contributes to the aims of the
war, and help combatants and commanders to better identify the demands of
necessity with regards to each operation, given that operation’s contribution
to some particular war aim.
CROEs as Guides in Situations of NEC-Civilian/NEC-
Enemy Conflict
The second type of necessity conflict, and one which is increasingly preva-
lent in the asymmetric forms of war that have become the norm, is conflict
between the demands of NEC-Civilian and NEC-Enemy. The core of this con-
flict is rooted in the fact that in the securing of one’s war aims, it will often
be possible to reduce harm to civilians at the cost of imposing (more) harm
Page 38
on combatants, and vice versa. Moreover, since the principle of necessity
extends protections to both groups, there is no clear guide for determining
how to distribute the harms. This problem is further compounded by the
fact that while both groups are given protections by necessity, civilians enjoy
further protections (notably via the principles of discrimination and propor-
tionality), complicating a simple balancing of the necessity claims of civilians
and combatants. And finally, even assuming that some balancing of claims
were to be possible, it would still be unreasonable to demand that combat-
ants and commanders undertake such nuanced and subtle moral and legal
judgments while under fire. The simple fact is that soldiers in highly stress-
ful fast-paced combat environments need clear guides for action which are
easy to follow and which will not admit significant errors in decision-making
under stress.
My proposal is to develop Rules of Engagement (ROEs) which are de-
signed to provide such a guide, and do so in a fashion that does not down-
play the strength of any demands of necessity, and which allows combatants
and commanders to exercise a measure of moral/legal judgment, while also
giving them assistance in making such decisions. It is worth noting that this
is certainly not the only way to provide a way past conflicts of NEC-Civilian
and NEC-Enemy, but it is a method which is rather simple, allows for judg-
ment on the part of combatants, and also taps into the underlying demands
of the core principle of necessity, thus getting the best of each strategy for
dealing with conflict discussed in section C. Moreover, ROEs providing spe-
cific guidance during a conflict are common to most militaries around the
world, and so such a proposal would not necessitate any drastic alteration of
current state practice.
ROEs ‘are meant to be brief directives which inter alia emphasize crit-
ical aspects of the laws of war relevant to a specific mission.’73 As such,
73Roberts and Guelff, supra note 25, at 561 (emphasis in original). For further reading
on ROEs see also Sagan, S. D. (1991). Rules of engagement. Security Studies, 1(1):78–
Page 39
the guidance they provide is supplemental to the directives of the LOAC,
meaning that ROEs will only ever give a distillation of the laws of war or a
more restrictive standard than that found in the laws of war. In order for an
ROE to be effective, it must be simple enough to be easily employed during
combat situations, while still providing standards which, if followed, make
combatants more likely to act in accordance with morality and law than they
would without the ROE. Thus, good ROEs are written in plain language and
utilize notions familiar to combatants and commanders.
For the purposes of aiding combatants and commanders faced with con-
flicts of NEC-Civilian and NEC-Enemy, I propose the following ROE:
1. All civilians (and other protected persons) enjoy special protections
against being intentionally targeted or disproportionately harmed. As
such, in cases where reducing harm to the enemy conflicts with reducing
harm to civilians (or other protected persons), you are required to defer
as much harm as possible to the enemy, unless:
(i) you are absolutely convinced that there exists a method or means
of attack that only minimally increases (risk of) harm to civilians
while greatly reducing (risk of) harm to the enemy;
(ii) you are very confident that the reduced harm to the enemy now
will not result in an increased harm to civilians later; and
(iii) the alternative methods and means of attack will not violate any
other laws of war, in particular, the principle of discrimination.
2. Based on the information available to you, can you reduce harm to the
enemy without thereby placing civilians at greater risk?
2.1 If so, then carry out the action that reduces harm to the enemy.
108; and Cooper, C. G. (2014). Rules of engagement demystified: A study of the history,
development and use of roes. Mil. L. & L. War Rev., 53:189–246.
Page 40
2.2 If not, then reduce harm to the enemy only if you are certain
that the reduction in harm to the enemy greatly outweighs any
increased risks to civilians.
2.3 If you are unsure about the balance of (risked) harms to the enemy
and to civilians, then direct your harm towards the enemy to the
greatest possible extent.
3. No reduction in harm to the enemy can justify the use of otherwise
forbidden weapons or tactics.
This ROE reaffirms the protections afforded to both combatants and
civilians, highlighting as well that civilians (and other protected persons) are
to be given special consideration when weighing harms. Moreover, the ROE
allows for judgment on the part of combatants and commanders, and allows
for responses that are sensitive to the information available and the realities
of a given combat situation. For ease of understanding and application, the
ROE is split into three distinct components.
The first component, paragraph 1 (and its subsections), presents the gen-
eral conditions which should guide a soldier’s decisions. These general con-
ditions may be seen as encapsulations of the core principles of NEC-Civilian
and NEC-Enemy (and necessity simpliciter), and are intended to direct a
soldier’s attention toward the underlying moral and legal constraints. Com-
ponent 2 (and its subsections) presents a highly simplified decision-procedure
for soldiers to follow. The point of this is to provide a direct guide to action
that is easy to employ and that uses terminology and reasoning with which
combatants and commanders will be familiar. Component 3 draws attention
to the fact that no matter what good outcomes might be achieved, forbidden
weapons and tactics are still unconditionally forbidden. The purpose of this
is to forcefully remove from consideration any potential weapons or tactics
that might reduce harm overall but which are in breach of law.
In order for an ROE such as this to be effective, it will require that soldiers
Page 41
be trained to utilize it in situations similar to those they will encounter in
combat. Thus, wargames, simulations, and other training exercises will be
needed to ingrain the decision-procedures outlined in this ROE. However,
provided such training is given, it is likely that combatants and commanders
operating with this ROE in mind would be able to move past the many
conflicting duties of necessity that arise in modern warfare. Moreover, any
increased ability to navigate the competing demands of necessity should be
viewed as a significant victory, given how much of modern war takes place
amongst civilian populations, thus making conflicts and decisions like those
discussed all too common.
DApplication of this ROE to Concrete Cases
In order to briefly show how this ROE would function in actual practice,
let us apply it to the second case presented in section B above. In that
case we imagined that some counterinsurgent (COIN) forces needed to cross
an urban area in which insurgents had positioned themselves. We further
imagined that though the COIN forces needed to move past the insurgents,
there was virtually no military value in engaging the insurgents directly.
Our final assumption was that the COIN forces had two equally effective
alternatives for moving forward, to either use live ammunition and kill the
insurgents, or to deploy smoke grenades and move through the area while
the insurgents were incapable of seeing them.
In this case, the demands of NEC-Civilian and NEC-Enemy pull in dif-
ferent directions, the former demanding that the former course of action
be undertaken, and the latter demanding the latter. Yet by applying the
proposed ROE, we can move past this conflict, and do so in a way that is
straightforward and tracks our intuitions well. To see this, we need only
envision a COIN soldier applying the ROE to the case.
The COIN soldier knows that civilians enjoy greater protections than
combatants, but he also knows that combatants are still protected, and that
Page 42
he can trade some harms from one group to the other. As such, he begins to
go through the ROE line by line. Condition (i) is straightforwardly satisfied,
given that he knows he has the second equally effective alternative of using
smoke grenades. Condition (ii) is plausibly also satisfied, as the soldier has
no reason to believe that insurgents will pose any threat to the populace
once he and his fellow combatants have passed.74 Condition (iii) is also
satisfied, as the use of smoke grenades does not violate any law of war, and
the soldier is not actually targeting any civilians (the harms they suffer are
rather side-effects of the soldier’s method of moving forward).75 Moving onto
condition 2, the soldier then asks whether he can reduce harm to the enemy
without placing civilians at greater risk. He cannot, and so he skips 2.1, and
looks to 2.2. Condition 2.2 enjoins him to only reduce harm to his enemy
if he is certain that the reduction in harm to the enemy greatly outweighs
any increased harm to civilians. This is the case, and so the soldier may
conclude that he ought to opt for the use of smoke grenades rather than live
ammunition. Thus, the ROE provides a clear way past what was before a
clear conflict between demands of necessity. Moreover, the answer given by
the ROE is that which we would intuitively take to be the right course of
action; in using smoke grenades, the incredibly small and passing harm to
civilians is massively outweighed by the reduced harm of not killing one’s
enemy, and so it is better to impose that small harm for the sake of one’s
enemy.76
74If circumstances make it likely that this will not be the case, then the soldier may
indeed have reason to use lethal ammunition and targeting now.
75For discussion on doing versus allowing harm and on intending versus foreseeing harm,
see Quinn, W. (1989). Actions, intentions, and consequences: The doctrine of doing and
allowing. The Philosophical Review, 98(3):287–312; or Frowe, H. (2010). Killing john to
save mary: A defense of the moral distinction between killing and letting die. In Campbell,
J. K., O’Rourke, M., and Silverstein, H. S., editors, Action, Ethics, and Responsibility,
pages 47–66. MIT Press. For a response to these positions, see, e.g., Fischer, J. M.,
Ravizza, M., and Copp, D. (1993). Quinn on double effect: The problem of “closeness”.
Ethics, 103(4):707–725.
76Coincidentally, this is also the strategically superior option from a counterinsurgency
Page 43
If we imagine variations of this case, we can also see different ways the
ROE may function. For example, if the soldier has different (equally effective)
options which impose different levels of harm on the enemy, but none put
civilians at greater risk, then the ROE will simply tell the soldier to opt for
the option that is least harmful to the enemy. In such a case, the ROE thus
lines up directly with the demands of NEC-Enemy. Or if the soldier has
incomplete information, or is unsure of how much harm his different options
will impose on the enemy and on civilians, then the ROE will demand that
he direct as much harm as possible toward the enemy rather than civilians
(in line with the demands of the principle of precautions in attack; e.g. AP I,
Art. 57). And no matter what the soldier may achieve with his actions, the
ROE always stresses that forbidden weapons and tactics remain forbidden,
no matter what seeming good might be gained by using such weapons and
tactics. Thus, the ROE is flexible where it matters, allowing for information
and judgment to come into play in decision-making, while still remaining rigid
on key things like the express forbiddances of the LOAC. Most importantly,
the ROE proposed provides the exact guidance needed when the demands
of the various types of necessity conflict, and it does so using language and
reasoning that is familiar to combatants and commanders.
6 Conclusion
It is a remarkable achievement that the ethics of war have been able to
impact so heavily on the laws of war. However, the particular ways the
laws of war have evolved has created the possibility for normative conflicts
perspective. For current U.S. doctrine on COIN operations, see US Army/US Marine
Corps (2014). FM 3-24 Insurgencies and Countering Insurgencies. Technical report, United
States Army. See also Wood, N. G. (forthcoming). Necessity and the “War on Terror”:
Lessons from the U.S. Army/Marine Corps counterinsurgency manual. In Hawkins, T.
and Kim, A., editors, Just War Theory in an Age of Terror. Palgrave Macmillan for an
exploration of necessity in the context of COIN operations.
Page 44
to arise. Moreover, normative conflicts may arise between rules which are
rooted in one and the same ethical principle. On the face of it, this is nothing
particularly novel – most normative regimes give rise to at least some conflicts
– but it is problematic given the moral weight of decisions in war, and the
fact that one cannot simply slow things down and figure out what exactly to
do or which rule ought to be observed. The unfortunate truth is that war is
stressful, fast-paced, and commanders will sometimes make mistakes. And
when the demands of different principles conflict, mistakes may become the
norm.
In an attempt to alleviate this risk, I have explored the most likely con-
flicts which might arise between the various rules based in necessity, and
proposed two methods for dealing with said conflicts. The proposed rules are
constructed so as to be of use to combatants and commanders, using tools
familiar to them, like ROEs or directives on operational planning. However,
even though these address the more common sources of conflict, the proposals
certainly do not address all possible conflicts. Necessity is a central principle
in the laws of war, underpinning many diverse areas of regulation, and the
discussion above only touches on a fraction of those rules based in necessity.
As such, there remains room for much further research. In particular, it is of
great interest how rules protecting the environment or cultural heritage, both
of which have formulations hearkening to necessity, may relate to those rules
that protect civilians or combatants. Moreover, the conflicts that may arise
between these various rules will likely require separate strategies for dealing
with them. Such strategies will need to address the relative weights of all of
these principles, how they stand with regards to one another, as well as to
the many other principles regulating war. The law of war has come a long
way, but mistakes are still made today, and some of those mistakes are born
of the fact that the laws of war themselves can lead to conflict, confusion,
and uncertainty. It is my hope that continuing research will provide clarity
in this domain, so that combatants and commanders may one day act in
Page 45
confidence that they are following all of the demands of morality and law.
Page 46
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