Section F: Direct Participation in Hostilities

[Commentary]


  1. According to customary and treaty law applicable in both international and non-international armed conflict, civilians benefit from protection against direct (Rule 11) and indiscriminate (Rule 13) attacks unless and for such time as they take a direct part in hostilities.[270] Thus, for the duration of their direct participation in hostilities, civilians are lawful targets (see Rule 10 (b) (iii)).
  2. Despite the serious legal consequences involved, treaty law does not provide a definition of direct participation in hostilities. The notion must therefore be interpreted in good faith in accordance with the ordinary meaning to be given to its constituent terms in their context and in light of the object and purpose of the law of international armed conflict.[271]
  3. In essence, the notion comprises two components, namely that of “hostilities” and that of “direct participation” therein. While the concept of “hostilities”[272] refers to the collective resort by the Belligerent Parties to means and methods of injuring the enemy,[273] “participation” in hostilities refers to the individual involvement of a person in these “hostilities”. Depending on the quality and degree of such involvement, individual participation in hostilities may be described as “direct” or “indirect”. Indirect participation in hostilities does not lead to a loss of protection against direct attacks. The term “hostilities” is a generic term which corresponds to the sum total of all hostile acts carried out in an armed conflict.[274] The notion is wider than the notion of “attack”.
  4. Section F applies in its entirety also to non-international armed conflict, it being understood that there is no substantive difference between the adjective “active” — appearing in common Art. 3 of the Geneva Conventions[275] — and the more commonly used adjective “direct”.[276]
  1. Art. 51 (3) of AP/I: “Civilians shall enjoy the protection afforded by this Section, unless and for such time as they take a direct part in hostilities.”
    Art. 13 (3) of AP/II: “Civilians shall enjoy the protection afforded by this Part, unless and for such time as they take a direct part in hostilities.”
  2. Art. 31 (1) of the Vienna Convention on the Law of Treaties (23 May 1969, 1155 U.N.T.S. 331): “A treaty shall be interpreted in good faith in accordance with the ordinary meaning to be given to the terms of the treaty in their context and in the light of its object and purpose.”
  3. See the 1907 Hague Regulations, Section II of which is entitled “Hostilities”. Treaty law does not establish uniform terminology for the conduct of hostilities but refers, apart from “hostilities”, also to concepts such as:

    - “warfare”, used in the title of Part III of AP/I (“Methods and Means of Warfare…”) as well as in the title of Section I of Part III of AP/I (“Methods and Means of Warfare”). Expression also used in Art. 35 (1) of AP/I, see fn. 131;
    - “military operations”, for example used in Art. 53 of GC/IV: “Any destruction by the Occupying Power of real or personal property belonging individually or collectively to private persons, or to the State, or to other public authorities, or to social or cooperative organizations, is prohibited, except where such destruction is rendered absolutely necessary by military operations.”;
    The expression “military operations” is also used in Art. 51 (1) of AP/I: “1. The civilian population and individual civilians shall enjoy general protection against dangers arising from military operations. To give effect to this protection, the following rules, which are additional to other applicable rules of international law, shall be observed in all circumstances.”; and Art. 13 (1) AP/II (“The civilian population and individual civilians shall enjoy general protection against the dangers arising from military operations. …”);
    - or simply “operations”, as used for example in Art. 48 of AP/I (see fn. 193).
  4. Art. 43 (2) of AP/I: “Members of the armed forces of a Party to a conflict (other than medical personnel and chaplains covered by Article 33 of the Third Convention) are combatants, that is to say, they have the right to participate directly in hostilities.”

    Art. 45 (1) of AP/I (“Protection of persons who have taken part in hostilities”): “A person who takes part in hostilities and falls into the power of an adverse Party…”

    Art. 45 (3) of AP/I: “Any person who has taken part in hostilities, who is not entitled to prisoner-of-war status…”

    Art. 51 (3) of AP/I, see fn. 270.

    Art. 67 (1) (e) of AP/I, see fn. 513.

    Art. 13 (3) AP/II, see fn. 270.
  5. Some treaty provisions also the use of the term “hostile act”. See, e.g., Art. 41 (2) of AP/I (see fn. 226) and Art. 42 (2) of AP/I (see fn. 679).
  6. For the text of Common Art. 3 to the Geneva Conventions, see fn. 118. The expression of “persons taking no active part in the hostilities” appears in (1) of the said Common Article 3.
  7. The terms “active” (Common Art. 3 to the Geneva Conventions) and “direct” (Art. 51 (3) of AP/I; Art. 43 (2) of AP/I; Art. 67 (1) (e) of AP/I and Art. 13 (3) AP/II) refer to the same quality and degree of individual participation in hostilities. See also: ICTR, The Prosecutor v. Jean-Paul Akayesu, Case No. ICTR-96-4-T, Judgment of 2 September 1998, Para. 629 (“The class of victims”): “… the Indictment reads: ‘The victims referred to in this Indictment were, at all relevant times, persons not taking an active part in the hostilities’. This is a material averment for charges involving Art. 4 inasmuch as Common Art. 3 is for the protection of ‘persons taking no active part in the hostilities’ (Common Art. 3(1)), and Art. 4 of Additional Protocol II is for the protection of, “all persons who do not take a direct part or who have ceased to take part in hostilities”. These phrases are so similar that, for the Chamber’s purposes, they may be treated as synonymous.”

Rule 28

Civilians lose their protection from attack if and for such time as they take a direct part in hostilities.

[Commentary]

  1. Rule 28 is exclusively concerned with the “protection of civilians from attack” and has no bearing on other protections accorded to civilians, such as those which apply during detention.
  2. The phrase “for such time” is not in dispute as a reflection of customary international law. What it means is that, ordinarily, once direct participation in hostilities is over, the civilian concerned can no longer be attacked. However, three major controversial issues have emerged.
  3. The first issue concerns the exact moment in time at which direct participation in hostilities begins and, similarly, the exact moment when it ends. On this, opinions are divided. One view — reflected in the ICRC Interpretive Guidance[277] — takes the position that only concrete preparatory measures and deployment constitute the earliest point of direct participation, and withdrawal from the particular engagement terminates it.[278] The opposing view is that one could go “downstream” and “upstream” as far as the causal connection would stretch. For example, an individual acquiring materials in anticipation of building an improvised explosive device would qualify as a direct participant in hostilities from the moment of doing so.
  4. The second issue relates to the question of individuals who are members in non-State organized armed groups. Civilians who directly participate in hostilities may act entirely on an individual ad hoc basis. Often, however, non-State organized armed groups emerge which are joined by multiple individual civilians. Such groups, while organized and while participating in hostilities on behalf of one Belligerent Party and against another, do not necessarily “belong” to the Party which they generally support.[279] Of course, if they belong to a Belligerent Party they become part of its armed forces and are no longer civilians, i.e. they are combatants. There is no question that, if such organized armed groups belong to a Belligerent Party, the members are susceptible to attack at all times. The bone of contention relates to non-State organized armed groups in an international armed conflict which do not belong to a Belligerent Party. One view is that if an individual is a member of such a group, that person (at least when in a combat role) is continuously to be regarded as a civilian taking a direct part in hostilities, irrespective of any specific military action against the enemy. The other view, reflected in the ICRC Interpretive Guidance,[280] is that members of an organized armed group not belonging to a Party to the international armed conflict must either be regarded as organized criminals retaining their civilian status or, if the violence reaches the required thresholds of intensity and organization, may qualify as a Party to a separate non-international armed conflict. In the latter case, the organized armed group qualifies as the armed forces of that Party and the individuals concerned lose their civilian status.
  5. The third issue relates to the question of the so-called “revolving door” phenomenon, whereby a person directly participates in hostilities on a recurrent basis (in the mode of “farmer by day, fighter by night”). According to one view, the issue of membership in a non-State organized armed group does not exhaust the possibilities of the revolving door phenomenon and anyone who is attempting to be a “farmer by day, fighter by night” is to be considered as directly participating in hostilities at all times, meaning that he can be attacked in between military operations. According to the other view, absent membership in an organized armed group, each specific act of direct participation in hostilities must be considered in isolation from the others. Hence, the fact that the same individual is recurrently participating in hostilities, does not mean that he can be attacked in between these specific acts.
  6. Loss of protection against attack does not mean that the individuals concerned fall outside the protection of the law. The force used against civilians directly participating in hostilities must fully comply with the law of international armed conflict.
  7. Finally, it ought to be noted that organized armed violence failing to qualify as an international or non-international armed conflict remains an issue of law-enforcement.
  1. ICRC Interpretive Guidance, at pages 65–68.
  2. In accordance with this view, general preparation and capacity building (such as civilian factory workers producing weapons, ammunition and military equipment) may contribute to the general war effort but traditionally is not regarded as direct participation in hostilities.
  3. However, according to the ICRC, directly participating in hostilities “on behalf” of a party means nothing else than “belonging to” that party.
  4. ICRC Interpretive Guidance, at page 24.

Rule 29

Subject to the circumstances ruling at the time, the following activities are examples  of what may constitute taking a direct part in hostilities:

[Commentary]
  1. Defending of military objectives against enemy attacks.
    [Commentary]
  2. Issuing orders and directives to forces engaged in hostilities; making decisions on operational/tactical deployments; and participating in targeting decision-making.
    [Commentary]
  3. Engaging in electronic warfare or computer network attacks targeting military objectives, combatants or civilians directly participating in hostilities, or which is intended to cause death or injury to civilians or damage to or destruction of civilian objects.
    [Commentary]
  4. Participation in target acquisition.
    [Commentary]
  5. Engaging in mission planning of an air or missile attack.
    [Commentary]
  6. Operating or controlling weapon systems or weapons in air or missile combat operations, including remote control of UAVs and UCAVs.
    [Commentary]
  7. Employing military communications networks and facilities to support specific air or missile combat operations.
    [Commentary]
  8. Refueling, be it on the ground or in the air, of a military aircraft which is about to engage in, or which is engaged in, air or missile combat operations.
    [Commentary]
  9. Loading ordnance or mission-essential equipment onto a military aircraft which is about to engage in, or which is engaged in, air or missile combat operations.
    [Commentary]
  10. Servicing or repairing of a military aircraft which is about to engage in, or which is engaged in, air or missile combat operations.
    [Commentary]
  11. Loading mission control data to military aircraft/missile software systems.
    [Commentary]
  12. Combat training of aircrews, air technicians and others for specific requirements of a particular air or missile combat operation.
    [Commentary]

  1. According to the ICRC Interpretive Guidance,[281] a specific act amounting to direct participation in hostilities must meet three cumulative requirements: (i) a threshold regarding the harm likely to result from the act; (ii) a relationship of direct causation between the act and the expected harm; and (iii) a belligerent nexus between the act and the hostilities conducted between the Belligerent Parties. Applied in conjunction, these three requirements permit a reliable distinction between activities amounting to direct participation in hostilities and activities which, although occurring in the context of an armed conflict, are not part of the hostilities and, therefore, do not entail loss of protection against direct attack.
  2. In the ICRC Interpretive Guidance, the “threshold of harm”[282] requirement is explained as follows. For a specific act to qualify as direct participation in hostilities, the harm likely to result from it must attain a certain threshold. This threshold is reached, most notably, by adversely affecting the military operations or military capacity of a Belligerent Party (e.g., use of weapons against the armed forces, interrupting their deployments). Alternatively, the threshold can also be reached by inflicting death, injury, or destruction on persons or objects protected against direct attack (e.g., shelling or bombardment of residential areas, sniping against individual civilians). Direct participation in hostilities does not require the materialization of harm reaching the threshold but merely the objective likelihood that the conduct in question will result in such harm. Therefore, the relevant threshold determination must be based on “likely” harm, that is to say, harm which may reasonably be expected to result from an act in the prevailing circumstances.
  3. The “direct causation”[283] requirement is explained in the ICRC Interpretive Guidance in the following manner. The civilian population has always contributed to the general war effort, whether through the production and provision of arms, equipment, food, and shelter, or through economic, administrative, and political support. In order to qualify as “direct” rather than “indirect” participation in hostilities, however, there must be a direct causal relation between the act in question and the resulting harm. In this context, direct causation means that the harm is brought about in one causal step. Therefore, acts that merely build or maintain the capacity of a Belligerent Party to harm its adversary in unspecified future operations do not amount to “direct” participation in hostilities, even if they are connected to the resulting harm through an uninterrupted chain of events or are indispensable to its causation (e.g., production of weapons and ammunition, general recruiting and training of personnel). Nonetheless, the notion of direct participation in hostilities can include acts which cause harm only in conjunction with other acts (e.g., providing targeting information as part of a specific combat operation), most notably where the act in question is an integral part of a coordinated tactical operation that directly causes the required threshold of harm.
  4. The “belligerent nexus”[284] requirement is explained in the ICRC Interpretive Guidance as being an act amounting to direct participation in hostilities must not only be objectively likely to inflict harm meeting the first two criteria, but it must also be specifically designed to do so in support of a Belligerent Party and to the detriment of another. Belligerent nexus relates to the objective purpose and design of an act or operation as part of the conduct of hostilities and does not depend on the subjective mindset or intent of every participating individual. Armed violence which is not designed to harm a Belligerent Party, or which is not designed to do so in support of another Party, cannot amount to “participation” in hostilities taking place between these Parties. Thus, as a general rule, harm would remain of non-belligerent nature if it is caused: (a) in exercise of authority over persons or territory having fallen into the power of a party to the conflict (e.g., lawful and unlawful use of force against prisoners); (b) as part of civil unrest against such authority (e.g., violent demonstrations or riots); (c) in individual self-defence against violence prohibited by the law of international armed conflict (e.g., civilians forcibly defending themselves against marauding soldiers); (d) during inter-civilian violence (e.g., uncontrolled looting due to breakdown of law and order); or (e) for reasons otherwise unrelated to the conduct of hostilities (e.g. murder or arson for private motives).
  5. It must be noted that the three criteria established by the ICRC Interpretive Guidance — as summarized in paras. 2 − 4 of the Commentary on this Rule — were not unanimously accepted by the Group of Experts. It was maintained by a number of members of the Group of Experts that these criteria are not part of existing law and impose inappropriate constraints on the scope of direct participation in hostilities.
  6. It is important to stress that the activities listed in Rule 29 are “examples” which may only amount to a direct participation in hostilities “[s]ubject to the circumstances ruling at the time”. According to the ICRC, these examples can amount to direct participation in hostilities only if they meet the three cumulative requirements of threshold of harm, direct causation and belligerent nexus set out in its Interpretive Guidance.
  1. ICRC Interpretive Guidance, “Direct Participation in Hostilities as a Specific Act”, at pages 43–45 and “Constitutive Elements of Direct Participation in Hostilities”, at pages 46–64.
  2. ICRC Interpretive Guidance, at pages 47–50.
  3. ICRC Interpretive Guidance, at pages 51–58.
  4. ICRC Interpretive Guidance, at pages 58–64.

  1. The conduct of hostilities comprises not only offensive, but also defensive acts of violence against the enemy. In principle, therefore, the defence of military objectives against enemy attacks is a clear case of direct participation in hostilities. On the definition of “attacks”, see Rule 1 (e). On the definition of military objectives, see Rule 1 (y) and Rule 22.
  2. Particularly where Belligerent Parties resort to the use of private contractors, it may not always be easy to determine the precise nature of their activities. For example, when they are assigned to defend certain persons or objects, the line between such defence against enemy attacks (amounting to direct participation in hostilities) and against crime or violence unrelated to the hostilities (qualifying as law-enforcement, defence of self or others) may be thin.

Rule 29 (ii) shows that direct participation in hostilities includes acts which are likely to directly harm the enemy (e.g., tactical and operational planning to do harm), even though the person planning does not actually carry out the plan and may be geographically remote from where the plan is carried out.

  1. On the definition of CNAs, see Rule 1 (m). On the definition of electronic warfare, see Rule 1 (p).
  2. Depending on the precise nature of CNA, they may directly cause death, injury or destruction, or system malfunctions adversely affecting the military capacity or military operations of the enemy. When such operations do so, they may amount to direct participation in hostilities. However, mere hacking into the intranet of a military base will not automatically fall under Rule 29 (iii).

“Target acquisition” covers the identification and localization of targets for engagement. It encompasses providing detailed intelligence data about enemy forces and locating them with sufficient accuracy to permit continued monitoring or target designation and engagement.

Planning as well as preparation of a mission involving air or missile attacks can amount to direct participation in hostilities, whereas involvement in the planning of the war effort in general is insufficiently specific to meet the requirements of direct participation in hostilities.

The use of weapons systems during combat operations will almost invariably qualify as direct participation in hostilities. It bears clarifying, however, that no temporal or geographic proximity is necessarily required. While the use of delayed (e.g., mines, booby-traps or timer-controlled devices), or remote-controlled (e.g., missiles, UAV/UCAV) weapons-systems may be temporally or geographically remote from the resulting harm, such activities may qualify as direct participation in hostilities.

  1. To the extent that the use of communications networks and facilities supports specific air or missile combat operations — e.g., through the transmission of orders, intelligence, or other tactical data — such activities qualify as direct participation in hostilities.
  2. Rule 29 (vii) applies only to the use of military communications networks and facilities. Whether the use of civilian networks and facilities constitutes direct participation in hostilities will depend on the special circumstances of such use.

  1. The refuelling of military aircraft engaged in, or about to engage in, air or missile combat operations amounts to direct participation in hostilities because it constitutes either a part of an ongoing hostile act or, respectively, a measure preparatory to such an act.
  2. Conversely, the refuelling of military aircraft that are neither engaged in, nor about to engage in air or missile combat operations does not necessarily qualify as direct participation in hostilities.
  3. “[A]bout to” means that the engagement of the aircraft in a specific air or missile combat operation is imminent.

  1. The loading of ordnance or equipment onto military aircraft engaged in, or about to engage in, air or missile combat operations constitute either a part of an ongoing hostile act or, respectively, a measure preparatory to such an act and, therefore, amounts to direct participation in hostilities.
  2. Conversely, the loading of ordnance or equipment onto military aircraft that are neither engaged in, nor about to engage in, combat operations does not qualify as direct participation in hostilities.
  3. On the expression “about to”, see paragraph 3 of the Commentary on Rule 29 (viii).

  1. The servicing and repairing of military aircraft engaged in, or about to engage in, air or missile combat operations constitute either a part of an ongoing hostile act or, respectively, a measure preparatory to such an act and, therefore, amounts to direct participation in hostilities.
  2. Conversely, the servicing and repairing of military aircraft that are neither engaged in, nor about to engage in, combat operations, may maintain or build the military capacity of a party to the conflict, but does not qualify as direct participation in hostilities (e.g. regular maintenance).
  3. On the expression “about to”, see paragraph 3 of the Commentary on Rule 29 (viii).

  1. The loading of mission control data to software systems of military aircraft/missiles always amounts to direct participation in hostilities.
  2. The term “mission” means that the loading of data is part of an air or missile operation.
  3. “Mission control data” refers to data for a specific sortie.
  4. Rule 29 (xi) does not apply to the loading of mission control data for medical aircraft.

  1. The preparation and training of aircrews, air technicians and others with a view to the execution of a predetermined air or missile combat operation constitutes a measure preparatory to a specific hostile act and, therefore, amounts to direct participation in hostilities. This follows from the fact that the training needs to be for “specific requirements of a particular air or missile combat operation”.
  2. Conversely, general preparation and training of aircrews, air technicians and others for unspecified military operations to be executed in the future may maintain or enhance the military capacity of a party to the conflict, but does not qualify as direct participation in hostilities.