1. The principle of distinction is the “foundation on which the codification of the laws and customs of war rests”.^[191] First set forth in the 1868 St. Petersburg Declaration,^[192] then reaffirmed in Art. 48 of AP/I,^[193] the principle is intended to protect against direct attack: (a) civilians unless and for such time as they directly participate in hostilities (see Section F); (b) civilian objects as distinct from military objectives (see Rule 1 (y) and Section E). The principle of distinction also underpins such obligations as the prohibition of indiscriminate attack (see Rule 13), compliance with the principle of proportionality (see Rule 14) and the requirement to take feasible precautions in attack (see Section G).
2. In its Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons, the ICJ has recognized the distinction as one of the two “cardinal” principles of international humanitarian law, the other being the prohibition of unnecessary suffering.^[194] The ICJ, in that Advisory Opinion, stated: “States must never make civilians the object of attack and must consequently never use weapons that are incapable of distinguishing between civilian and military targets.”^[195] The principle of distinction is indisputably a principle of customary international law.
3. Rule 10 (a), by confining attacks to lawful targets, rules out direct or indiscriminate attacks against civilians (unless and for such time as they are directly participating in hostilities, see Section F). Nevertheless, in warfare, civilians and civilian objects are often harmed, despite not being the object of direct or indiscriminate attack. This is principally related to collateral damage, governed by the principle of proportionality (see Rule 14).
4. An attack is unlawful if aimed at other than a lawful target (see Rule 10 (b)), even if it ultimately fails to cause actual harm.
5. Rule 10 (a) applies also in non-international armed conflict.

191. Para. 1863 of the ICRC Commentary on AP/I, pertaining to the Commentary on Art. 48 of AP/I.
192. Second paragraph of the Preamble to the 1868 St. Petersburg Declaration: “That the only legitimate object which States should endeavour to accomplish during war is to weaken the military forces of the enemy.”
193. Art. 48 of AP/I: “In order to ensure respect for and protection of the civilian population and civilian objects, the Parties to the conflict shall at all times distinguish be¬tween the civilian population and combatants and between civilian objects and military objectives and accordingly shall direct their operations only against military objectives.”
194. ICJ, Nuclear Weapons Advisory Opinion, at Para. 78.
195. Ibid.

This Rule applies also in non-international armed conflict, although the term “combatant” is reserved for international armed conflict. Thus, like members of the regular armed forces of the State concerned, members of a non-State organized armed group in a non-international armed conflict are lawful targets.^[196]

196. According to the ICRC’s Interpretative Guidance on the notion of direct participation in hostilities, organized armed groups in a non-international armed conflict consist only of individuals whose continuous function it is to take a direct part in hostilities (“continuous combat function”).

1. The customary definition of combatants, originating in Art. 1 of the 1907 Hague Regulations,^[197] is found in Art. 4 (A) (1) and in Art. 4 (A) (2) of GC/III.^[198]
2. Combatants include all members of the armed forces of a Belligerent Party, except medical or religious personnel. The armed forces include the officially organized military forces, as well as organized armed forces, groups and units under a command responsible to a Party to the conflict and responsible for his subordinates; which wear a distinctive sign (e.g., clothing or other accoutrements) that distinguish them from the civilian population; carry their weapons openly; and which generally conduct their operations in accordance with the laws and customs of warfare.
3. Paramilitary or other armed law-enforcement agencies may be incorporated into the armed forces. When this occurs, the members of such agencies become combatants. In other words, incorporation renders them lawful targets. Art. 43 (3) of AP/I requires such incorporation to be notified to the other Belligerent Party.^[199] However, failure to so notify the enemy does not bar their treatment as lawful targets.
4. Disagreement exists as to whether individuals who do not meet the aforementioned criteria, but nevertheless participate directly in the hostilities, are to be characterized as “civilians” or “unprivileged belligerents” (also termed “unlawful combatants”) (see paragraph 4 of the Commentary on the chapeau to Rule 111 (b). The issue whether they are “unprivileged belligerents” is relevant only to the rules governing their detention (as POW, civilian internees or under some other category). However, it is clear that civilians who participate directly in hostilities can be attacked or captured no matter whether they are characterized as “civilians” or as “unprivileged belligerents” (see Section F).
5. Persons, including combatants, who are hors de combat may not be attacked (see Rule 15 (b)).
6. Certain categories of individuals are singled out in the law of international armed conflict as enjoying specific protection because of the functions they serve. Apart from medical and religious personnel (see Section K), this refers to civil defence personnel which may not be attacked unless they commit acts harmful to the enemy (see Section N (I)). It ought to be noted that civil defence functions can be performed by a military unit. The personnel will remain protected, provided that they are permanently assigned and exclusively devoted to the performance of civil defence tasks (see Art. 67 of AP/I).^[200] The performance of recognized civil defence functions is in this connection not considered harmful to the enemy, even when amounting to putting out a fire on a military objective, if the fire endangers the life of civilian persons or threatens civilian objects in the vicinity (see paragraph 3 of the Commentary on Rule 1 (k)).

197. Art. 1 of the 1907 Hague Regulations: “The laws, rights, and duties of war apply not only to armies, but also to militia and volunteer corps fulfilling the following conditions: (1) To be commanded by a person responsible for his subordinates; (2) To have a fixed distinctive emblem recognizable at a distance; (3) To carry arms openly; and (4) To conduct their operations in accordance with the laws and customs of war. In countries where militia or volunteer corps constitute the army, or form part of it, they are included under the denomination ‘army’.”
198. Art. 4 of GC/III: “(1) Members of the armed forces of a Party to the conflict as well as members of militias or volunteer corps forming part of such armed forces. (2) Members of other militias and members of other volunteer corps, including those of organized resistance movements, belonging to a Party to the conflict and operating in or outside their own territory, even if this territory is occupied, provided that such militias or volunteer corps, including such organized resistance movements, fulfil the following conditions: (a) that of being commanded by a person responsible for his subordinates; (b) that of having a fixed distinctive sign recognizable at a distance; (c) that of carrying arms openly; (d) that of conducting their operations in accordance with the laws and customs of war.”
199. Art. 43 (3) of AP/I: “Whenever a Party to a conflict incorporates a paramilitary or armed law enforcement agency into its armed forces it shall so notify the other Parties to the conflict.”
200. Art. 67 of AP/I, see fn. 513.

1. Military objectives, as defined in Rule 1 (y), are classified by nature, location, purpose or use. The criteria of use, location or purpose may turn an otherwise civilian object into a military objective in certain circumstances (see Rule 22).
2. Under Art. 59 (2) of AP/I, a Belligerent Party may declare any inhabited place in or near the contact zone as a non-defended locality (subject to several conditions, such as that all combatants, mobile weapons and mobile military equipment must have been evacuated, that no hostile use will be made of fixed military installations or establishments located therein).^[201] The concept goes back to Art. 25 of both the 1899^[202] and the 1907^[203] Hague Regulations.^[204] A declared non-defended locality must not be attacked. However, the entire construct is based on the idea that it is situated in or near the contact zone, thereby allowing the enemy to enter the locality whenever it desires.

201. Art. 59 (2) of AP/I: “The appropriate authorities of a Party to the conflict may declare as a non-defended locality any inhabited place near or in a zone where armed forces are in contact which is open for occupation by an adverse Party. Such a locality shall fulfil the following conditions: (a) all combatants, as well as mobile weapons and mobile military equipment must have been evacuated; (b) no hostile use shall be made of fixed military installations or establishments; (c) no acts of hostility shall be committed by the authorities or by the population; and (d) no activities in support of military operations shall be undertaken.”
202. Art. 25 of the 1899 Hague Regulations: “The attack or bombardment of towns, villages, habitations or buildings which are not defended, is prohibited.”
203. Art. 25 of the 1907 Hague Regulations: “The attack or bombardment, by whatever means, of towns, villages, dwellings, or buildings which are undefended is prohibited.”
204. Art. 59 (1) of AP/I: “It is prohibited for the Parties to the conflict to attack, by any means whatsoever, non-defended localities.”

Civilians who directly participate in hostilities lose their immunity from attack for such time as they so participate (see Section F). Although they have no combatant rights, they may be directly attacked like combatants. Yet, once they become hors de combat they are subject to — and benefit from — the application of Rule 15 (b).

1. This Rule is based on the 1868 St. Petersburg Declaration,^[205] reaffirmed in the first sentence of Art. 51 (2) of AP/I^[206] and in Art. 52 (1) of AP/I.^[207]
2. It is necessary to distinguish between two modes of attacks against civilians or civilian objects, which are equally prohibited: (i) Rule 11 addresses the issue of attacks directed against civilians or civilian objects; (ii) Rule 13 deals with an “indiscriminate attack”, which is not directed against a specific person or object. Such an attack strikes lawful targets without distinction from civilians or civilian objects.
3. Directing attacks against civilians or civilian objects is prohibited regardless of the purpose. Nor is it important whether the attack is successful.
4. In time of armed conflict, attacks against civilians or civilian objects may result from a weapons system’s malfunction. For the purposes of Rule 11, this will not qualify as “attacks directed against civilians or civilian objects”. Thus, for example, if a guided missile loses its homing capability, i.e. “goes ballistic”, this will not qualify as an attack prohibited under Rule 11.
5. The prohibition of Rule 11 cannot eliminate cases of human error in targeting. The issue of mistake of fact is particularly relevant in case of criminal legal proceedings against the person. See Art. 32 (1) of the Rome Statute of the ICC.^[208]
6. For the purpose of Rule 11, a civilian is any person who is not a combatant. However, a civilian loses protection against direct attack if, and for such time as, he directly participates in hostilities (see Section F).
7. Civilian objects, as defined in Rule 1 (j), are all objects that are not military objectives as defined in Rule 1 (y). The protection does not apply to civilian objects that have become military objectives through location, purpose or use (see Rule 22 (b)−(d)).
8. Rule 11 applies also in non-international armed conflict.
205. Second operative paragraph of the 1868 St. Petersburg Declaration: “That the only legitimate object which States should endeavour to accomplish during war is to weaken the military forces of the enemy.”
206. First sentence of Art. 51 (2) of AP/I: “The civilian population as such, as well as individual civilians, shall not be the object of attack.”
207. Art. 52 (1) of AP/I: “Civilian objects shall not be the object of attack or of reprisals. Civilian objects are all objects which are not military objectives as defined in paragraph 2.”
208. Art. 32 (1) of the Rome Statute of the ICC: “A mistake of fact shall be a ground for excluding criminal responsibility only if it negates the mental element required by the crime.” Art. 30 of the Rome Statute of the ICC further deals with this “mental element”.

1. This Rule is based on Art. 50 (1) of AP/I.^[209]
2. All feasible precautions must be taken in order to verify that attacks are directed at lawful targets (see Rule 32 (a) and Rule 35 (a)). Rule 12 (a) applies when, after a verification process, there is still doubt.
3. Indications that a person is a lawful target, either as a combatant or as a civilian taking a direct part in hostilities, will depend on the circumstances. For instance, in some societies, it is normal for males to carry a firearm routinely. In other environments, similar behaviour could be regarded as conclusive evidence of membership in a non-State organized armed group.
4. It is often the case in aerial operations that some uncertainty exists regarding status of a person as a civilian. The degree of doubt necessary to preclude an attack is that which would cause a reasonable attacker in the same or similar circumstances to abstain from ordering or executing an attack.
5. The issue of doubt as to whether a person is a civilian, is of special importance in the context of direct participation in hostilities (see Section F).
6. Rule 12 (a) applies also in non-international armed conflict.
209. Second sentence of Art. 50 (1) of AP/I: “In case of doubt whether a person is a civilian, that person shall be considered to be a civilian.”

1. This Rule is based on Art. 52 (3) of AP/I.^[210]
2. Rule 12 (b) only relates to the category of military objectives through “use”. In other words, the situation involves enemy forces using for military ends an object that is normally dedicated to civilian purposes. Art. 52 (3) of AP/I offers “a place of worship, a house or other dwelling or a school” as examples of objects which are normally dedicated to civilian purposes. These examples are considered to be only illustrative. The buildings that are mentioned do not have any special status compared to other typically civilian buildings or installations. Additional examples are commercial offices, shopping areas and facilities and markets.^[211]
3. All feasible precautions must be taken in order to verify that attacks are directed at lawful targets (see Rule 32 (a) and Rule 35 (a)). Rule 12 (b) applies when, after a verification process, there is still doubt.
4. Doubt is often present in situations of armed conflict. Rule 12 (b) clarifies the standard. It is not the existence of any doubt that precludes attack, but rather reasonable doubt. In other words, an attacker must act reasonably in deciding to attack such objects, specifically taking into account, among other factors, the fact that the intended target is normally one used for civilian purposes. The attacker would also have to take into account the reliability of the information that indicates that the object is used for military purposes. If there is reason to doubt the reliability of the information, one cannot reasonably act on that basis.
5. The status of the object believed to be used for military purposes need not be established beyond reasonable doubt. A reasonable conclusion to the effect that an object is being so used will suffice. A military commander always has to deal with situations of doubt when choosing between alternative courses of action, weighing expected benefits against risks. The same holds true when there is an uncertainty as to whether an object which is ordinarily dedicated to civilian purposes is being used for military purposes.
6. In some situations, the enemy will use places of worship for military purposes as a matter of routine, for instance as observation posts or as a snipers’ perch. Before an attack is launched, it has to be established that the particular place of worship is used for military purposes. One may also have to take into account that the place of worship could, in the circumstances ruling at the time, be used as a refuge by civilians. On this subject, see inter alia Rule 14 on the principle of proportionality; Rule 32 (b) on avoiding — or, in any event, minimizing — collateral damage, as well as Rule 35 (c)); and Rule 45 regarding the prohibition against using civilians as “human shields”.
7. “Information” includes military intelligence. The quality and timeliness of the intelligence has to be considered. Other information, such as visual observations on the spot that may corroborate or contradict military intelligence, must also be taken into account.
8. There will often be hindsight information that was not available at the time of the attack. The question is, however, whether there was doubt at the time when the decision was taken, as well as when the attack is actually launched (see paragraph 4 of the Commentary on Rule 1 (q) and paragraph 5 of the Commentary on Rule 14). Provided that all feasible precautions were taken (as per Rule 32 (a) and Rule 35 (a)) to verify that the target was a lawful target (see Rule 10), additional information that turns up at some later point in time (perhaps as a result of the attack) is irrelevant.
9. Objects normally dedicated to civilian purposes that are being used for military purposes by the enemy regain protected status (although they may still be considered military objectives by purpose, see Rule 22 (c)). Under Rule 1 (j), everything that is not a military objective is a civilian object.
210. Art. 52 (3) of AP/I: “In case of doubt whether an object which is normally dedicated to civilian purposes, such as a place of worship, a house or other dwelling or a school, is being used to make an effective contribution to military action, it shall be presumed not to be so used.”
211. Para. 5.4.2 of the UK Manual: “In cases of doubt, objects that are normally used for civilian purposes are to be presumed as not being used for military purposes. Such objects would include churches, dwelling houses, residential flats, commercial offices and factories, shopping precincts and markets, schools, and libraries.”

1. This Rule is based on Art. 51 (4) of AP/I.^[212]
2. Whether an attack is indiscriminate is typically a case-specific determination. Relevant factors include, but are not limited to indications of the attacker’s indifference; the nature of the weapons employed; and the location and density of civilians or civilian objects relative to military objectives.
3. Rule 13 (a) applies also in non-international armed conflict.
212. Art. 51 (4) of AP/I: “Indiscriminate attacks are prohibited. Indiscriminate attacks are: (a) those which are not directed at a specific military objective; (b) those which employ a method or means of combat which cannot be directed at a specific military objective; or (c) those which employ a method or means of combat the effects of which cannot be limited as required by this Protocol; and consequently, in each such case, are of a nature to strike military objectives and civilians or civilian objects without distinction.”

     See also the first sentence of subpara. 2 of Para. 5.3.2 of NWP: “The principle of distinction, combined with the principle of military necessity, prohibits indiscriminate attacks.”

1. This Rule is based on Art. 51 (4) of AP/I.
2. Indiscriminate attacks may result from either the employment of indiscriminate methods (tactics) or means (weapons) of warfare. On the latter, see also Rule 5 (a).
3. Indiscriminate attacks, just like attacks directed against civilians or civilian objects (see Rule 11) need to be distinguished from instances of a weapons system’s malfunction or from human error. As long as a weapon was originally aimed at a lawful target, the fact that it or its weapons system malfunctions (e.g., when a missile “goes ballistic) and as a result hits civilians or civilian objects, does not alter the fact that it was “directed” against a lawful target. See also paragraph 4 and paragraph 5 of the Commentary on Rule 11.
4. If enemy defences or countermeasures deflect a weapon (not otherwise indiscriminate) from its intended target, causing it to strike civilians or civilian objects, the attack will not be deemed indiscriminate (on this ground).
5. Even when target identification and weapons guidance systems are used, an attack may become indiscriminate due to inclement weather conditions or similar reasons. Attacks at night may likewise not be possible to execute with sufficient discrimination using available equipment and weapons.
6. The question of whether the effects of an attack against a target in proximity of civilians or civilians objects is indiscriminate, may depend on such factors as the nature of the target, choice of weapons and meteorological conditions. For an example, see the 2007 judgment of the ICTY Trial Chamber in the Martic case. The Tribunal held that firing non-guided rockets with cluster munitions at a densely populated civilian area, from a distance of approximately 50 kilometers, constituted an indiscriminate attack.^[213]
7. An aircraft that releases a weapon over an area in which civilians or civilian objects are likely to be present, without regard for where it will hit, will have conducted an indiscriminate attack. This includes an aircraft which chooses to jettison weapons prior to returning to base. However, in extreme circumstances, it is permissible to release the weapons over a sparsely populated area with a few scattered farms or cottages.
8. Attacks using missiles and other projectiles fired from beyond visual range (“over the horizon”, see Commentary on Rule 7 pertaining to “beyond visual range weapons systems”) are not as such indiscriminate when their employment permits distinguishing military objectives and combatants from civilians and civilian objects. This may be done through sensors on the weapon itself, or through external guidance, for instance from the aircraft. Indeed, the technological systems used to identify a target and prosecute such attacks can be far more reliable than the naked eye.
9. An operation must qualify as an “attack” (see Rule 1 (e)) before being prohibited as “indiscriminate”. For instance, a psychological operation directed against the civilian population which does not cause death/injury to civilians, or destruction/damage of civilian objects does not violate the law of international armed conflict (provided that it is not intended to terrorize civilians, see Rule 18). On this issue in particular, see Rule 21.
10. Rule 13 (b) applies also in non-international armed conflict.

213. ICTY, Prosecutor v. Milan Martic, Case No. IT-95-11-T, Judgment by the Trial Chamber of 12 June 2007, at paras. 462–463.

1. This Rule is based on Art. 51 (5) (a) of AP/I.^[214] It is also found in other treaties and in military manuals such as in NWP^[215] and in the UK Manual.^[216]
2. Rule 13 (c) is derived from the acute need to cope with the problem of “target area” bombing that arose in WWII. The text seriously limits the possibilities in which clusters of military objectives may be attacked as if they were a single lawful target. On the other hand, it does not deny the possibility that a number of lawful targets, which are not clearly separated and distinct, may be treated as a single lawful target.
3. As the experience of WWII demonstrated, recourse to “target area” bombing may cause devastation on an unprecedented scale because of the location of lawful targets — which are not clearly separated and distinct — within a city, or other residential area. However, it must be borne in mind that, under the current law of international armed conflict, all attacks are subject to the principle of proportionality (see Rule 14) and the requirement to take feasible precautions in attack (see Section G). Hence, the expected collateral damage to civilians and civilian objects must not be excessive compared to the anticipated military advantage.
4. As in other instances when the attacker is facing the risk of a breach of the principle of proportionality, the availability of precision guided weapons may facilitate striking lawful targets in a manner that will avoid — or, in any event, minimize — the expected collateral damage to civilians or civilian objects (see Rule 8).
5. Rule 13 (c) applies also in non-international armed conflict.
   214. Art. 51 (5) of AP/I: “Among others, the following types of attacks are to be considered as in¬discriminate: (a) an attack by bombardment by any methods or means which treats as a single military objective a number of clearly separated and distinct military objectives located in a city, town, village or other area containing a similar concentration of civilians or civilian objects; and (b) an attack which may be expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects, or a combination thereof, which would be excessive in relation to the concrete and direct military advantage anticipated.”
   215. Second subpara. of Para. 5.3.2 of NWP: “attacks that employ a method or means of combat that cannot be directed at a specific military objective (e.g., declaring an entire city a single military objective and attacking it by bombardment when there are actually several distinct military objectives throughout the city that could be targeted separately)”.
   216. Para. 5.23.2 of the UK Manual: “The following are examples of indiscriminate attacks: (a) an attack by bombardment by any methods or means which treats as a single military objective a number of clearly separated and distinct military objectives located in a city, town, village or other area containing a similar concentration of civilians or civilian objects; …”

1. This Rule is based on Art. 51 (5) (b) of AP/I,^[217] and is often referred to as the principle of proportionality.
2. “Collateral damage” does not include inconvenience, irritation, stress, fear or other intangible conditions caused to the civilian population. It is limited to death/injury to civilians, or to damage/destruction of objects. For the definition of collateral damage, see Rule 1 (l).
3. In the context of air or missile combat operations, it is often unavoidable that civilians or civilian objects will be harmed during attacks on lawful targets, especially in circumstances in which military objectives are located in proximity to civilians or civilian objects, or when civilians are located within a military objective. In such cases, the attack may proceed so long as the principle of proportionality and the requirements of Section G are complied with. If an attack would not be possible without excessive collateral damage to civilians or civilian objects being expected, as compared to the anticipated military advantage, the attack is prohibited despite being directed against a lawful target. For the definition of “military advantage”, see Rule 1 (w).
4. The members of the Group of Experts could not agree as to what extent (if at all) indirect (“reverberating”) effects of attacks have to be factored into the proportionality calculation. In any event, there is no dispute that indirect effects cannot be taken into account if they are too remote or cannot be reasonably foreseen. The Group of Experts could identify no conclusive State practice that settles the issue of indirect effects of attacks.
5. The key to the application of Rule 14 lies in the terms “expected” and “anticipated.” The principle of proportionality is not dealing with hindsight. What counts is not hindsight, but foresight (see paragraph 4 of the Commentary on Rule 1 (q) and paragraph 4 of the Commentary on Rule 12 (a)). Foresight includes taking feasible precautions (see Section G) and assessing the likely consequences of the attack that is being planned, bearing in mind the anticipated military advantage. The consequences that actually flow from an attack come into play in the course of an ex post facto evaluation of whether the attacker ought reasonably to have expected the resulting collateral damage. But the issue is expectations and not results (see also paragraph 8 of the Commentary on Rule 12 (b) with regard to hindsight in case of doubt).
6. The standard is objective in that expectations must be reasonable. If the attacker expected, in light of reliable information available at the time, that the collateral damage to civilians or civilians would be excessive relative to the anticipated military advantage, the principle of proportionality will have been violated. “Expected” collateral damage and “anticipated” military advantage, for these purposes, mean that that outcome is probable, i.e. more likely than not. Both terms assume a good-faith assessment by the commander planning or approving the attack, or the combatant executing it. They are “judged in the light of the information reasonably available” at the time.^[218] Moreover, it must be acknowledged that mistakes occur due to the “fog of war” or when it turns out reality did not match expectations, perhaps due to faulty intelligence. An attack does not violate the principle of proportionality unless such mistakes were unreasonable in the circumstances. See Section G on feasible precautions in attacks.
7. The term “excessive” is often misinterpreted. It is not a matter of counting civilian casualties and comparing them to the number of enemy combatants that have been put out of action. It applies when there is a significant imbalance between the military advantage anticipated, on the one hand, and the expected collateral damage to civilians and civilian objects, on the other.
8. The fact that collateral damage is extensive does not necessarily render it excessive. The concept of excessiveness is not an absolute one. Excessiveness is always measured in light of the military advantage that the attacker anticipates to attain through the attack. If the military advantage anticipated is marginal, the collateral damage expected need not be substantial in order to be excessive. Conversely, extensive collateral damage may be legally justified by the military value of the target struck, because of the high military advantage anticipated by the attack.^[219]
9. The term “concrete and direct” refers to military advantage that is clearly identifiable and, in many cases, quantifiable.^[220] Of course, not always is the military advantage easy to establish and anticipate. On the other hand, it is clear that for the military advantage to be concrete and direct, it cannot be based merely on hope or speculation.
10. The term “military advantage” must not be too narrowly construed, for instance by restriction to ground gained or weakening the enemy armed forces (see paragraph 3 of the Commentary on Rule 1 (w)). This is especially true in aerial warfare. An attack can for instance be an element in a ruse (see Section Q, in particular Rule 116 (a)). The security of the attacking forces is also a component of military advantage,^[221] as would be general disruption of command and control communications. On the other hand, the term “military advantage” must not be interpreted too broadly: it is limited to impact on the enemy’s military tactical or operational level. Thus, for instance, even if striking military objectives weakens the morale of the enemy civilian population (see Rule 18), this effect is not in itself a relevant “military advantage” for the purpose of Rule 14.
11. It is generally accepted as a matter of customary international law that “the military advantage anticipated from an attack is intended to refer to the advantage anticipated from the attack considered as a whole and not from isolated or particular parts of the attack”^[222] , a standard adopted in the Rome Statute of the ICC.^[223] This means that it is necessary to consider the military operation in its entirety and not merely the military advantage immediately accruing from the attack at the time that it is conducted. For instance, an attack on a bridge to deny the enemy the capability to cross a river may seemingly be of low military advantage if the enemy is actually not using that bridge. However, if the purpose of the attack on the bridge is to block avenues of retreat which the commander knows will be taken once he launches his planned offensive, the military advantage of destroying the bridge will be high. On this issue, see also paragraph 6 of the Commentary on Rule 1 (w), paragraph 7 of the Commentary on Rule 1 (y) and paragraph 3 of the Commentary on Rule 33.
12. Aerial attacks are often conducted by multiple military aircraft, in which case it would be improper to consider the impact of each single sortie in isolation. It is rather necessary to assess the overall mission. To consider military advantage in light of the “attack as a whole” has also other aspects. One example could be a contemplated series of attacks against a number of bridges across the same river when they are in proximity to each other. Although the first attack on one of these bridges might appear to yield only a limited military advantage, considering that the enemy can still use the remaining bridges, the military advantage will become apparent once subsequent attacks against the other bridges take place.
13. “An attack considered as a whole” ought not to be confused with the entire armed conflict, but could refer to a large air campaign. For example, a series of air attacks may be directed against military objectives in one zone — in anticipation of a military operation in another — as a ruse to deceive the enemy regarding the actual location of the intended operations (see Rule 116 (a)). Although the expected collateral damage to civilians or civilian objects resulting from the attacks might be excessive if viewed solely from the perspective of the advantage gained from individual target destruction, it must instead be considered in terms of the ruse’s value relative to the military operations elsewhere.
14. Opinions in the Group of Experts were divided as to whether civilians who are physically within a military objective (e.g., civilian employees working in a munitions factory) count for the purposes of the application of the principle of proportionality. Three views were expressed. Some experts were of the opinion that such civilians do not count because they have chosen to be there and have thereby voluntarily assumed the risk of an attack by the enemy. The majority of the Group of Experts felt that the principle of proportionality applies to such civilians as in all other cases. However, some experts — while belonging to that majority — pointed out that the application of the principle of proportionality will not make a material difference when the target is a high-value asset (such as a munitions factory), referring to the fact that extensive casualties do not necessarily amount to excessive collateral damage.
15. The principle of proportionality applies throughout all stages of an attack, from planning to execution. Anyone with the ability and authority to suspend, abort or cancel an attack, must do so once he reaches the conclusion that the expected collateral damage would be excessive in relation to the anticipated military advantage. For instance, a pilot who has the target in view and unexpectedly observes civilians in the target area — who were not supposed to be there, based on the information provided to him during the briefing preceding the attack — must assess the collateral damage expected to befall them and cancel the attack if he concludes that the principle of proportionality will be violated. See Rule 32 (b) and Rule 35 (c).
16. National or policy requirements to seek approval of a specified level of command whenever collateral damage reaches a predetermined level are not a substitute for the application of the principle of proportionality in accordance with the law of international armed conflict. A decision by higher echelons to approve a planned attack will not render lawful an attack which violates Rule 14.
17. Rule 14 applies also in non-international armed conflict.

217. Art. 51 (5) (b) of AP/I, see fn. 214.
218. Para. 5.20.4. of the UK Manual.
     
     See also the UK statement of understanding made on ratification of AP/I: “Military commanders and others re-sponsible for planning, deciding upon, or executing attacks necessarily have to reach decisions on the basis of their assessment of the information from all sources which is reasonably available to them at the relevant time.”
219. Para. 1980 of the the ICRC Commentary on AP/I, in connection with Art. 51 of AP/I, disagrees with this view: “The idea has also been put forward that even if they are very high, civilian losses and damages may be justified if the military advantage at stake is of great importance. This idea is contrary to the fundamental rules of the Protocol; in particular it conflicts with Art. 48 (Basic rule) and with paragraphs 1 and 2 of the present Art. 51. The Protocol does not provide any justification for attacks which cause extensive civilian losses and damages. Incidental losses and damages should never be extensive.” The ICRC interpretation of Art. 51 of AP/I is not, however, found to be customary law.
220. Para. 2209 of the ICRC Commentary, in connection with to Art. 57 (2) (b) of AP/I states that the expression “concrete and direct military advantage” “was intended to show that the advantage concerned should be substantial and relatively close, and that advantages which are hardly perceptible and those which would only appear in the long term should be disregarded.”
221. The term “military advantage” involves a variety of considerations, including the security of attacking forces, see declarations made by Australia and New Zealand upon ratification of AP/I : “In relation to paragraph 5 (b) of Art. 51 and to paragraph. 2 (a) (iii) of Art. 57, [it is our understanding] that … the term “military advantage” involves a variety of considerations, including the security of attacking forces. …”
222. The UK has given the following understanding to Art. 57 of AP/I: “In the view of the United Kingdom, the military advantage anticipated from an attack is intended to refer to the advantage anticipated from the attack considered as a whole and not only from isolated or particular parts of the attack.” Similar understandings have also been given by, for example, Australia, Canada, Germany and The Netherlands.
223. Art. 8 (2) (b) (iv) of the Rome Statute of the ICC, see fn. 84.

1. This Rule is based on Art. 40 of AP/I.^[224] See also Art. 23 (d) of the 1907 Hague Regulations.^[225]
2. There was some debate in the Group of Experts as to whether it was necessary to have Rule 15 (a) in the Manual, considering that the subject of denial of quarter is also covered in Rule 126 in the context of surrender. The majority of the Group of Experts felt, however, that the issue of denial of quarter — and what is equally important, the threat thereof — is wider in scope and must therefore also be incorporated in Section D.
3. The emphasis in Rule 15 (a) is on the fact that a policy of “taking no any prisoners” is entirely inadmissible, and it cannot be threatened, even in advance of any fighting and, therefore, before the issue of surrender becomes relevant.
4. Persons who surrender or give themselves up for capture no longer pose a threat to the enemy (see Section S, in particular paragraph 3 of the Commentary on Rule 126). It is unlawful to kill or injure such persons regardless of whether they are combatants or civilians taking a direct part in hostilities.
5. Rule 15 (a) applies also in non-international armed conflict.

224. Art. 40 of AP/I (“Quarter”): “It is prohibited to order that there shall be no survivors, to threaten an adversary therewith or to conduct hostilities on this basis.”
225. Art. 23 of the 1907 Hague Regulations: “In addition to the prohibitions provided by special Conventions, it is especially forbidden: … (d) To declare that no quarter will be given.”

1. This Rule is derived from Art. 41 of AP/I.^[226] See also Art. 23 (c) of the 1907 Hague Regulations.^[227]
2. For the specific context of air or missile operations, there are two categories of persons hors de combat: (i) those who have clearly expressed an intention to surrender; (ii) those who are incapacitated. The latter category falls into three subsets: sick; wounded; and shipwrecked.
3. Upon due consideration, the majority of the Group of Experts decided not to retain the separate category of Art. 41 (a) of AP/I, i.e. persons “in the power of an adverse Party”, in view of the fact that such category is irrelevant in aerial warfare.
4. Although, as a term of art, the expression “hors de combat” is reserved for combatants, for the purposes of Rule 15 (b), it covers incapacitation of both combatants and civilians who have directly participated in hostilities.
5. Combatants (or civilians directly participating in hostilities) must communicate clearly their intention to surrender before becoming immune from attack. If a combatant (or a civilian directly participating in hostilities) does not indicate an intention to surrender in a way that the enemy can perceive and understand, this person is still liable to be attacked. For example, the crew of an attacking aircraft conducting a beyond-visual-range attack may be unaware that the forces they are attacking wish to surrender. As long as the lack of knowledge is reasonable in the circumstances, the attack may lawfully be conducted because the desire to surrender has not been effectively communicated to the aircrews (or other forces which could pass that information to the crew in adequate time).
6. In aerial warfare, it is often problematic to assess whether a person is hors de combat. When a person is in an aircraft in the air, his aircraft is not immune from attack and the person would have to suffer the consequences of an attack as long as the aircraft has not effectively communicated its intention to surrender (see Section S), although he may actually be wounded. When a person is lying on the ground, it is often difficult to determine from the air whether this is due to incapacitating injuries or because he is taking cover from aerial attack. Thus, it is essential to emphasize that the protection extends only to those who are hors de combat from the perspective of the reasonable attacker.
7. In the context of aerial warfare, it is possible to communicate an intention to surrender without actually being captured, for instance when a combatant on the ground surrenders to an aircraft (see dissenting view in the next paragraph). The protection against attack commences as soon as the intention to surrender has been clearly communicated to the enemy, for instance by throwing away one’s weapons and raising one’s arms. The display of a white flag by ground troops, which means a request to parley, is in practice also frequently used as a means of communicating an intention to surrender.
8. Opinions were sharply divided among the members of the Group of Experts as to whether it is possible for personnel on the ground or on board of ships to validly surrender to an aircraft that is not able to accept the surrender by taking prisoners. There were two views. Some members of the Group of Experts were of the opinion that it is irrelevant whether the aircraft can itself capture prisoners: those manifesting an intent to surrender may not be attacked. By contrast, other members of the Group of Experts insisted that an attack need not be aborted merely because someone on the ground is raising his hands or waving a white flag, since this could easily lead to misuse. All members of the Group of Experts agreed, however, that if a large unit surrenders collectively and ground forces can be summoned to take care of the surrendering enemy soldiers, they cannot be attacked. As to surrender, see Section S.
9. The Group of Experts agreed that those who manifest the intention to surrender must do so in good faith. If ground forces of a Belligerent Party repeatedly raise their hands in order to avoid attack from enemy military aircraft knowing that the military aircraft has no possibility to take prisoners, and continue to fight again when the aircraft has left, this could amount to perfidy (see Section Q, in particular Rule 114 (e)). Furthermore, such personnel cannot expect that similar behaviour on future occasions will be taken seriously as a genuine offer of surrender.
10. A person may be incapacitated (hors de combat) by wounds or sickness. The incapacitation does not have to be caused by the conflict. The concept includes persons who have suffered stroke, heart attack or food poisoning, and even mothers who are delivering babies.
11. The notion of incapacitation is contingent on the combatant (or the civilian taking direct part in hostilities) (i) not continuing to commit any act of hostility; and (ii) not trying to escape.^[228] Incapacitation ought not to be confused with lack of capability for defense. For instance, during an aerial attack, enemy forces may have no defensive means of warfare within range of the attacking aircraft. This does not render them hors de combat. If they wish to be exempt from attack, they must validly communicate an intention to surrender.
12. The terms “wounded”, “sick” and “shipwrecked” are defined in Art. 8 of AP/I. “Wounded” and “sick” are military or civilian persons in need of medical care and who refrain from all acts of hostility.^[229] “Shipwrecked” are military or civilian persons in a perilous situation at sea or on any other waters following a misfortune and who refrain from all acts of hostility. Under Art 8 (b) of AP/I the concept is expanded to include persons, who are in peril at sea or in other waters (including lakes).^[230] The term “shipwreck” means shipwreck from any cause and includes forced landings at sea by or from aircraft (first paragraph of Art. 12 of GC/II).^[231]
13. A person descending by parachute from an aircraft in distress is assimilated to persons hors de combat and must not be made the object of attack during his descent. Upon landing in a territory controlled by the enemy, the person who descended in distress must be given an opportunity to surrender (for details, see Section T, in particular Rule 132).
14. Rule 15 (b) applies also in non-international armed conflict.

226. Art. 41 of AP/I ‘(“Safeguard of an enemy hors de combat”): “(1) A person who is recognized or who, in the circumstances, should be recognized to be hors de combat shall not be made the object of attack. (2) A person is hors de combat if: (a) he is in the power of an adverse Party; (b) he clearly expresses an intention to surrender; or (c) he has been rendered unconscious or is otherwise incapacitated by wounds or sickness, and therefore is incapable of defending himself.”
227. Art. 23 of the 1907 Hague Regulations: “In addition to the prohibitions provided by special Conventions, it is especially forbidden: … (c) To kill or wound an enemy who, having laid down his arms, or having no longer means of defence, has surrendered at discretion.”
228. Para. 1610 of the ICRC Commentary on AP/I, in connection with Art. 41 (2) of AP/I: “In accordance with this paragraph, a person is considered to be rendered ‘hors de combat’ either if he is “in the power” of an adverse Party, or if he wishes to surrender, or if he is incapacitated. This status continues as long as the person does not commit any act of hostility and does not try to escape.”
229. Art. 8 (a) of AP/I: “‘Wounded’ and ‘sick’ mean persons, whether military or civilian, who, because of trauma, disease or other physical or mental disorder or disability, are in need of medical assistance or care and who refrain from any act of hostility. These terms also cover maternity cases, new-born babies and other persons who may be in need of immediate medical assistance or care, such as the infirm or expectant mothers, and who refrain from any act of hostility.”
230. Art. 8 (b) of AP/I: “‘Shipwrecked’ means persons, whether military or civilian, who are in peril at sea or in other waters as a result of misfortune affecting them or the vessel or aircraft carrying them and who refrain from any act of hostility. These persons, provided that they continue to refrain from any act of hostility, shall continue to be considered shipwrecked during their rescue until they acquire another status under the Conventions or this Protocol.”
231. First paragraph of Art. 12 of GC/II: “Members of the armed forces and other persons mentioned in the following Article, who are at sea and who are wounded, sick or shipwrecked, shall be respected and protected in all circumstances, it being understood that the term “shipwreck” means shipwreck from any cause and includes forced landings at sea by or from aircraft.”

1. This Rule is based on numerous provisions of the 1949 Geneva Conventions and of AP/I. The obligation to take all possible measures to search for, collect and protect the wounded, sick, shipwrecked and the dead is included in Art. 15 of GC/I;^[232] Art. 18 of GC/II;^[233] Art. 16 of GC/IV^[234] and Art. 10 of AP/I.^[235] Respect for the obligation to search for and collect the dead is a conditio sine qua non of respect for other rules of the law of international armed conflict concerning, e.g., the return of remains, decent burial and identification of the dead.
2. For the application of Rule 16 (a) in the specific context of air or missile operations, see Rule 19.
3. For the notion of “wounded”, “sick” and “shipwrecked”, see paragraph 12 of the Commentary on Rule 15 (b).
4. The requirement set forth in Rule 16 (a) applies “at all times”. In practice, however, the ability of a Belligerent Party to perform the activities referred to Rule 16 (a) may be determined by such factors as the availability of search and collection capabilities, weather, terrain, and the constraints of any ongoing hostilities.
5. Rule 16 (a) applies also in non-international armed conflict.

232. Art. 15 of GC/I: “At all times, and particularly after an engagement, Parties to the conflict shall, without delay, take all possible measures to search for and collect the wounded and sick, to protect them against pillage and ill-treatment, to ensure their adequate care, and to search for the dead and prevent their being despoiled. Whenever circumstances permit, an armistice or a suspension of fire shall be arranged, or local arrangements made, to permit the removal, exchange and transport of the wounded left on the battlefield. Likewise, local arrangements may be concluded between Parties to the conflict for the removal or exchange of wounded and sick from a besieged or encircled area, and for the passage of medical and religious personnel and equipment on their way to that area.”
233. Art. 18 of GC/II: “After each engagement, Parties to the conflict shall, without delay, take all possible measures to search for and collect the shipwrecked, wounded and sick, to protect them against pillage and ill-treatment, to ensure their adequate care, and to search for the dead and prevent their being despoiled. Whenever circumstances permit, the Parties to the conflict shall conclude local arrangements for the removal of the wounded and sick by sea from a besieged or encircled area and for the passage of medical and religious personnel and equipment on their way to that area.”
234. Art. 16 of GC/IV: “The wounded and sick, as well as the infirm, and expectant mothers, shall be the object of particular protection and respect. As far as military considerations allow, each Party to the conflict shall facilitate the steps taken to search for the killed and wounded, to assist the shipwrecked and other persons exposed to grave danger, and to protect them against pillage and ill-treatment.”
235. Art. 10 of AP/I (“Protection and care”): “(1) All the wounded, sick and shipwrecked, to whichever Party they belong, shall be respected and protected. (2) In all circumstances they shall be treated humanely and shall receive, to the fullest extent practicable and with the least possible delay, the medical care and attention required by their condition. There shall be no distinction among them founded on any grounds other than medical ones.”

1. The obligation to provide medical care and attention to the wounded, sick and shipwrecked is based on Art. 12^[236] and Art. 15^[237] of GC/I; Art. 12^[238] and Art. 18 of GC/II^[239] ; Art. 16 of GC/IV^[240] ; and Art. 10 of AP/I.^[241]
2. Rule 16 (b) applies to all wounded, sick, shipwrecked, and dead without adverse distinction. That is to say, there must be no prejudice against certain persons or categories of persons. In particular, distinctions founded on race, colour, sex, language, religion or belief, political or other opinion, national or social origin, wealth, birth or other status, are prohibited. See Art. 12 of GC/I;^[242] Art. 12 of GC/II^[243] and Art. 10 of AP/I.^[244]
3. The obligations under Rule 16 (b) are obligations of conduct and not of result. Each Belligerent Party must use its best efforts to implement these obligations, including acceptance of assistance offered by impartial humanitarian organizations when circumstances permit (see Rule 19 (c)).
4. The “wounded”, “sick” and “shipwrecked” referred to in Rule 16 (b) encompass not only (i); combatants; and (ii) civilians taking a direct part in hostilities; but also (iii) ordinary civilians.
5. Wounded and sick must be exclusively treated on the basis of medical priority rather than any other criterion. Thus, priority as regards air evacuation from a battlefield has to be given to enemy wounded and sick combatants if they are in more urgent need of medical assistance. Urgency of treatment is typically determined through triage.
6. Rule 16 (b) applies also in non-international armed conflict.

236. Art. 12 of GC/I: “Members of the armed forces and other persons mentioned in the following Article, who are wounded or sick, shall be respected and protected in all circumstances. They shall be treated humanely and cared for by the Party to the conflict in whose power they may be, without any adverse distinction founded on sex, race, nationality, religion, political opinions, or any other similar criteria. Any attempts upon their lives, or violence to their persons, shall be strictly prohibited; in particular, they shall not be murdered or exterminated, subjected to torture or to biological experiments; they shall not wilfully be left without medical assistance and care, nor shall conditions exposing them to contagion or infection be created. Only urgent medical reasons will authorize priority in the order of treatment to be administered. Women shall be treated with all consideration due to their sex. The Party to the conflict which is compelled to abandon wounded or sick to the enemy shall, as far as military considerations permit, leave with them a part of its medical personnel and material to assist in their care.”
237. Art. 15 of GC/I, see fn. 232.
238. Art. 12 of GC/II: “Members of the armed forces and other persons mentioned in the following Article, who are at sea and who are wounded, sick or shipwrecked, shall be respected and protected in all circumstances, it being understood that the term “shipwreck” means shipwreck from any cause and includes forced landings at sea by or from aircraft. Such persons shall be treated humanely and cared for by the Parties to the conflict in whose power they may be, without any adverse distinction founded on sex, race, nationality, religion, political opinions, or any other similar criteria. Any attempts upon their lives, or violence to their persons, shall be strictly prohibited; in particular, they shall not be murdered or exterminated, subjected to torture or to biological experiments; they shall not wilfully be left without medical assistance and care, nor shall conditions exposing them to contagion or infection be created. Only urgent medical reasons will authorize priority in the order of treatment to be administered. Women shall be treated with all consideration due to their sex.”
239. Art. 18 of GC/II, see fn. 233.
240. Art. 16 of GC/IV: “The wounded and sick, as well as the infirm, and expectant mothers, shall be the object of particular protection and respect. As far as military considerations allow, each Party to the conflict shall facilitate the steps taken to search for the killed and wounded, to assist the shipwrecked and other persons exposed to grave danger, and to protect them against pillage and ill-treatment.”
241. Art. 10 of AP/I (“Protection and Care”): “1. All the wounded, sick and shipwrecked, to whichever Party they belong, shall be respected and protected. 2. In all circumstances they shall be treated humanely and shall receive, to the fullest extent practicable and with the least possible delay, the medical care and attention required by their condition. There shall be no distinction among them founded on any grounds other than medical ones.”
242. Art. 12 of GC/I, see fn. 236.
243. Art. 12 of GC/II, see fn. 238.
244. Art. 10 of AP/I, see fn. 241.