Humanitarian law defines attacks as acts of violence against an adversary, whether carried out in offense or in defense, and in whatever territory conducted (API Art. 49.1).
The basic rule governing attacks is that the parties to a conflict must at all times distinguish between the civilian population and combatants, and between civilian objects and military objectives. The parties to the conflict may direct their operations only against military objectives. Consequently, indiscriminate attacks are prohibited (API Art. 48 and Rules 7, 11–13 of the ICRC customary IHL study).
Humanitarian law establishes that military commanders are under the obligation to take precautionary measures when preparing and carrying out attacks, so as to limit their possible detrimental effects and to ensure that they are not indiscriminate, and that the incidental harm on civilians is proportionate to the concrete and direct military advantage anticipated (API Art. 57, 58 and Rules 14–24 of the ICRC customary IHL study).
Protected Persons and Objects
International humanitarian law clearly defines the persons and objects that must be protected in times of armed conflict, both international and internal. It forbids intentionally launching attacks and reprisals against them. This stems from the principle of distinction. The following attacks are prohibited:
- Attacks against the civilian population as such, and acts or threats of violence the primary purpose of which is to spread terror among the civilian population (API Art. 51.2 and APII Art. 13).
- Attacks against civilians by way of reprisals (API Art. 51.6). The corollary to this is that parties to the conflict may not direct the movement of civilians in order to attempt to shield military objectives from attacks or to protect military operations, nor may they use the presence of a protected person to render certain points immune from military operations (GCIV Art. 28 and API Art. 51.7).
- Attacks against civilian and cultural objects and property, places of worship, objects indispensable to the survival of the civilian population, and works or installations containing dangerous forces that may cause damage to the natural environment and hence prejudice the health or survival of the population (API Arts. 52–56, APII Arts. 14–15). Humanitarian law defines the distinctive emblems and signs that must be used to signal the presence of such protected objects.
- Attacks on medical units and personnel (GCI Art. 19, GCII Art. 23, GCIV Art. 18, API Art. 12, and APII Art. 11).
- Attacks on demilitarized or neutral zones and undefended places (GCIV Art. 15 and API Art. 60).
▸ Civilians ▸ Distinctive (or protective) emblems, signs, and signals ▸ Human shields ▸ Humanitarian and relief personnel ▸ Medical duties ▸ Protected objects and property ▸ Protected persons
The Statute of the International Criminal Court, that was adopted on 17 July 1998, and entered into force on 1 July 2002, reaffirms that such attacks constitute war crimes, whether committed during international or internal armed conflicts (Art. 8 of ICC Statute). Furthermore, it states that “when committed as part of a widespread or systematic attack directed against any civilian population,” they constitute crimes against humanity (Art. 7 of ICC Statute).
▸ International Criminal Court ▸ War crimes/Crimes against humanity
Indiscriminate or Disproportionate Attacks
Humanitarian law prohibits any kind of indiscriminate attacks. Such attacks do not distinguish between military objectives and civilian persons or property. Such attacks are defined and prohibited in detail in Article 51 of the 1977 Additional Protocol I to the Geneva Conventions as well as in Rules 11, 12 and 13 of ICRC customary IHL study:
- attacks that are not directed at a specific military objective;
- attacks that employ a method or means of combat that cannot be directed at a specific military objective;
- attacks that employ a method or means of combat whose effects cannot be limited;
- attacks by bombardment, by any methods or means, that treat 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;
- attacks that may be expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects, or a combination thereof and that would be excessive in relation to the concrete and direct military advantage anticipated.
This last prohibition introduces the twofold notion of “proportionality” that must be respected: (1) Any attack must be in proportion to the threat that is faced, and any reprisal must be proportionate to the attack suffered. (2) The incidental civilian loss or damages must be proportionate with the military advantages. If this proportionality requirement is not followed, humanitarian law considers the attack to be indiscriminate. The requirement for the calculation of the proportionality of attacks has become a rule of customary law in conflict and non-international armed conflicts: “Launching 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, is prohibited” (Rule 14 of the customary IHL study).
▸ Bombardment ▸ Methods (and means) of warfare ▸ Proportionality ▸ Reprisals ▸ War
Precautions in Attack
Humanitarian law defines the precautionary measures that must be taken in the conduct of military operations so as to spare civilians and civilian objects. All the following precautionary measures have become norms of customary law applicable in international and non-international armed conflicts.
If military and civilian objectives are near one another, a certain number of specific precautions must be taken in carrying out an attack so as to limit any detrimental effects that civilians might incur (API Arts. 57, 58).
It is the responsibility of combatants, and in particular of commanders, to respect certain precautions during military attacks. Two articles establish the measures that must be applied to ensure that this principle is effective in practice. These rules are included in Additional Protocol I of 1977, applicable in international armed conflicts. However, because of their customary character, they may be applied to sustain the general principle of precaution in internal armed conflicts.
With respect to attacks, the following precautions shall be taken:
- Those who plan or decide upon an attack shall:
- do everything feasible to verify that the objectives to be attacked are neither civilians nor civilian objects and are not subject to special protection but are military objectives (Rule 15 and API art. 57) (. . .);
- 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 or civilian life, injury to civilians, and damage to civilian objects (Rules 16 and 17; API art. 57);
- refrain from deciding to launch any 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 (Rule 19; API art. 57).
- An attack shall be canceled or suspended if it becomes apparent that the objective is not a military one or is subject to special protection or that the attack 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 (API art. 57).
- Effective advance warning shall be given of attacks that may affect the civilian population, unless circumstances do not permit (API Art. 57.2 and Rule 20).
When a choice is possible between several military objectives that would result in a similar military advantage, the attack selected shall be the one that may be expected to cause the least danger to civilian lives and to civilian objects (API Art. 57.3 and Rule 21).
No provision of this article (art. 57) may be construed as authorizing any attacks against the civilian population, civilians, or civilian objects (API Art. 57.5).
Rules of Customary International Humanitarian Law Concerning Precaution in Attack
Customary humanitarian law (customary IHL study) has established precautionary measures that shall be taken against the effects of attacks.
- Rule 18: “Each party to the conflict must do everything feasible to assess whether the attack may be expected to cause incidental loss of civilian life, injury to civilians, damage to civilians objects, or a combination thereof, which would be excessive in relation to the concrete and direct military advantage anticipated.”
- Rule 19: “Each party to the conflict must do everything feasible to cancel or suspend an attack if it become apparent that the target is not a military objective or that the attack may be expected to cause incidental loss of civilian life, injury to civilians, damage to civilians objects, or a combination thereof, which would be excessive in relation to the concrete and direct military advantage anticipated.”
- Rule 22: “The parties to the conflict must take all feasible precautions to protect the civilian population and civilian objects under their control against the effects of attacks.”
Those three rules are applicable in international and non-international armed conflicts.
- Rule 23: “Each party to the conflict must, to the extent feasible, avoid locating military objectives within or near densely populated areas.”
- Rule 24: “Each party to the conflict must, to the extent feasible, remove civilian persons and objects under its control from the vicinity of military objectives.”
The two last rules are applicable in international armed conflicts but arguably in non-international armed conflicts.
Duty of Commanders
Commanders have the obligation to respect the precautionary measures described here. Furthermore, they must see to it that their subordinates also respect these rules. They therefore have the duty to ensure that members of the armed forces under their command, as well as other persons under their control, are aware of their obligations under the Geneva Conventions and Protocols and respect them. If members of the armed forces violate humanitarian law, commanders must take the necessary measures to end such acts and to initiate the disciplinary or penal action that is necessary against the perpetrators of such violations.
▸ Distinctive (or protective) emblems, signs, and signals ▸ Duty of commanders ▸ International humanitarian law ▸ Methods (and means) of warfare ▸ Military necessity ▸ Military objectives ▸ Proportionality ▸ Protected objects and property ▸ Protected persons ▸ Reprisals ▸ War
Judges had to analyze the lawfulness of attacks with regard to the respect of the principles of distinction, precaution, and proportionality between military necessity and damages caused to civilians ( ▸ Proportionality ). These principles are spelled out in Articles 57 and 58 of the 1977 Additional Protocol I. According to case law, they are now part of customary international law, not only because they specify and flesh out general preexisting norms, but also because they do not appear to be contested by any State, including those that have not ratified the Protocol ( Kupreskic Case , 14 January 2000, para. 524).
According to the principle of distinction, military commanders must distinguish between military objectives and civilian persons or objects. This principle is spelled out in Article 57 of Additional Protocol I to the Geneva Conventions, which obligates those who plan or decide upon an attack to “do everything feasible to verify that the objectives to be attacked are neither civilians nor civilian objects.” The obligation to do everything feasible is high but not absolute. Therefore, a determination that inadequate efforts have been made to distinguish between military objectives and civilians or civilian objects should not necessarily focus exclusively on a specific incident ( Final Report to the Prosecutor by the Committee Established to Review the NATO Bombing Campaign against the Federal Republic of Yugoslavia , ICTY, 13 June 2000, para. 29, available at http://www.un.org/icty/pressreal/nato061300.htm ).
For Additional Information: Bothe, Michael. “Terrorism and the Legality of Pre-emptive Force.” European Journal of International Law 14, no. 2 (2003): 227–40.
Dinstein, Yoram. The Conduct of Hostilities under the Law of International Armed Conflict . Cambridge: Cambridge University Press, 2004.
Hampson, Françoise. “The Law Applicable to Military Operations in the Twenty-first Century.” Revue de Droit Militaire et de Droit de la Guerre 38, no. 1/4 (1999): 329–31.
Henckaerts, Jean-Marie, and Louise Doswald-Beck, eds. Customary International Law . Vol. 1, The Rules . Cambridge: Cambridge University Press, 2005, esp. parts 1 and 5.
ICRC. “Protection of Civilian Persons and Populations in Time of War.” In Basic Rules of the Geneva Conventions and Their Additional Protocols , chapter 4. Geneva: ICRC, 1995.
Mulinen, Frederic de. “Conduct of Attack.” In Handbook on the Law of War for Armed Forces , 102–4. Geneva: ICRC, 1989.