Source: https://ihl-databases.icrc.org/customary-ihl/eng/docs/v2_cha_chapter5_rule18
Timestamp: 2019-04-21 07:16:07+00:00

Document:
Note: For practice concerning the principle of proportionality in general, see Rule 14, Section A.
Those who plan or decide upon an attack shall … 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.
Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts (Protocol I), Geneva, 8 June 1977, Article 57(2)(a)(iii). Article 57 was adopted by 90 votes in favour, none against and 4 abstentions. CDDH, Official Records, Vol. VI, CDDH/SR.42, 27 May 1977, p. 211.
(c) refrain from deciding to launch any attack which may be expected to cause incidental damage to cultural property protected under Article 4 of the Convention which would be excessive in relation to the concrete and direct military advantage anticipated.
(b) take into account the loss and destruction which the attack, even if carried out with the precautions prescribed under Article 9, is liable to inflict upon the civilian population. He is required to refrain from the attack if, after due consideration, it is apparent that the loss and destruction would be disproportionate to the military advantage anticipated.
Draft Rules for the Limitation of the Dangers Incurred by the Civilian Population in Time of War, drafted by the International Committee of the Red Cross, September 1956, submitted to governments for their consideration on behalf of the 19th International Conference of the Red Cross, New Delhi, 28 October–7 November, Res. XIII, Article 8(b).
An attack shall not be launched if it may be expected to cause collateral casualties or damage which would be excessive in relation to the concrete and direct military advantage anticipated from the attack as a whole.
Australia’s Defence Force Manual (1994) states that those responsible for deciding upon an attack must refrain from “launching any attack which may be expected to cause collateral injury, or collateral damage, which would be excessive in relation to the concrete and direct military advantage anticipated”.
Australia, Manual on Law of Armed Conflict, Australian Defence Force Publication, Operations Series, ADFP 37 – Interim Edition, 1994, § 556(f); see also Law of Armed Conflict, Commanders’ Guide, Australian Defence Force Publication, Operations Series, ADFP 37 Supplement 1 – Interim Edition, 7 March 1994, § 957(c).
Australia’s LOAC Manual (2006) states that it is the duty of Australian Defence Force commanders to refrain “from launching any attack which may be expected to cause collateral injury, or collateral damage, which would be excessive in relation to the concrete and direct military advantage anticipated”.
Everything possible must be done to avoid incidental damage to civilian objects and loss of civilian life: when this damage and this loss appears to be excessive in relation to the anticipated military advantage, the attack must not take place.
Benin, Le Droit de la Guerre, III fascicules, Forces Armées du Bénin, Ministère de la Défense nationale, 1995, Fascicule II, p. 6.
The principle of proportionality rests on the prohibition to launch attacks which will cause losses to civilian populations and damage to civilian objects which are excessive in relation to the anticipated military advantage.
Commanders, planners and staff officers have … to refrain from launching any attack which may be expected to cause collateral civilian damage which would be excessive in relation to the concrete and direct military advantage anticipated (proportionality test).
Canada, The Law of Armed Conflict at the Operational and Tactical Level, Office of the Judge Advocate General, 1999, p. 4-3, § 24.
c. to refrain from launching any attack which may be expected to cause collateral civilian damage which would be excessive in relation to the concrete and direct military advantage anticipated (proportionality test).
Canada, The Law of Armed Conflict at the Operational and Tactical Levels, Office of the Judge Advocate General, 13 August 2001, § 417.1.c.
A military commander who has been assigned a mission will have to take into consideration a number of elements when taking decisions. He will need intelligence about anything that could help him accomplish the mission. He then has to consider any precautions that will have to be taken to comply with the law. Lastly, he will have to analyse the prevailing tactical situation.
Central African Republic, Le Droit de la Guerre, Fascicule No. 3: Formation pour l’obtention du Brevet d’Armes No. 1, du Brevet d’Armes No. 2 et le stage d’Officier de Police Judiciaire (OPJ), Ministère de la Défense, Forces Armées Centrafricaines, 1999, Chapter II, Section II.
When analysing the tactical situation military commanders must consider all the specific prevailing circumstances, including military and humanitarian considerations. Military commanders must also consider any precautionary measures relative to the dangers to which a military action may expose civilian persons and objects.
Before taking his final decision a military commander has to assess the possible outcomes of his evaluation.
- the expected cost of the proposed action (likely losses among his own men, civilian losses, material damages).
Central African Republic, Le Droit de la Guerre, Fascicule No. 3: Formation pour l’obtention du Brevet d’Armes No. 1, du Brevet d’Armes No. 2 et le stage d’Officier de Police Judiciaire (OPJ), Ministère de la Défense, Forces Armées Centrafricaines, 1999, Chapter II, Section II, § 2.3, and Section III.
Naval commanders must take all reasonable precautions … In each instance, the commander must determine whether incidental injuries and collateral damage would be excessive, on the basis of an honest and reasonable estimate of the facts available to him.
France, Manuel de droit des conflits armés, Ministère de la Défense, Direction des Affaires Juridiques, Sous-Direction du droit international humanitaire et du droit européen, Bureau du droit des conflits armés, 2001, p. 49; see also p. 89.
Before engaging an objective, every responsible military leader shall … refrain from launching any attack which may be expected to cause incidental injury and damage to civilian life and objects which would be excessive in relation to the concrete and direct military advantage anticipated.
Israel, Laws of War in the Battlefield, Manual, Military Advocate General Headquarters, Military School, 1998, p. 40.
- refrain from an attack which may be expected to result in collateral damage on a scale which would be excessive in relation to the expected military advantage.
An attack should not proceed when an obvious lack of proportion appears to exist between expected military advantage and expected collateral damage. The decisive factor is whether a normally alert attacker, in receipt of and acting on due information, could have expected the excessive damage among the civilian population and civilian objects.
0546. When attacking mixed objects … it must be carefully considered whether the military advantage expected from eliminating the military element of the mixed objective outweighs the damage done to the civilian population, by damaging or destroying the civilian element of the mixed object or ending its civilian function. In any case, the disabling or destruction of the military element must yield a clear military advantage (cf. AP I [1977 Additional Protocol I] Article 52). In addition, the civilian population must not be excessively affected (cf. AP I Article 51).
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, §§ 0542, 0543 and 0546.
Precaution shall be taken to minimise civilian casualties and damage and the precaution comprises the respect for the rule of proportionality (civilian casualties not being excessive in relation to the military advantage anticipated).
Nigeria, International Humanitarian Law (IHL), Directorate of Legal Services, Nigerian Army, 1994, p. 45, § 16(b).
It shall not be decided to launch an attack when, from the information available at the time of the decision, it may be expected to cause damage to civilian persons and/or objects which would be excessive in relation to the concrete and direct military advantage anticipated from the attack as a whole and not only from isolated parts thereof.
Spain, Orientaciones. El Derecho de los Conflictos Armados, Publicación OR7-004, 2 Tomos, aprobado por el Estado Mayor del Ejército, División de Operaciones, 18 March 1996, Vol. I, § 2.5.b.
The decision to launch an attack must not be implemented when, based on information available at the time the decision is taken, it could be expected to lead to casualties among the civilian population or cause damage to civilian property which would be excessive in relation to the military advantage anticipated from the attack considered as a whole and not only from isolated or specific parts of the attack.
Spain, Orientaciones. El Derecho de los Conflictos Armados, Tomo 1, Publicación OR7–004, (Edición Segunda), Mando de Adiestramiento y Doctrina, Dirección de Doctrina, Orgánica y Materiales, 2 November 2007, § 2.5.b.
If the attack may be expected to entail such large losses in human life, injury to civilians or damage to civilian property, or a combination of these, that they may be judged excessive in relation to the anticipated concrete and direct advantage, the commander shall refrain from attacking.
Togo, Le Droit de la Guerre, III fascicules, Etat-major Général des Forces Armées Togolaises, Ministère de la Défense nationale, 1996, Fascicule II, p. 6.
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.
United Kingdom, The Manual of the Law of Armed Conflict, Ministry of Defence, 1 July 2004, § 5.32; see also § 13.32 (maritime warfare).
Those who plan or decide upon an attack must 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.
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 5-3(c)(1)(b)(i)(c).
Naval commanders must take all reasonable precautions … In each instance, the commander must determine whether the anticipated incidental injuries and collateral damage would be excessive, on the basis of an honest and reasonable estimate of the facts available to him.
The Socialist Federal Republic of Yugoslavia’s Military Manual (1988) states that “an attack undertaken with disproportionate means on a military objective of lesser importance in an urban settlement, which would lead to big casualties among the civilian population, is contrary to the international law of war”.
Under Ireland’s Geneva Conventions Act (1962), as amended in 1998, any “minor breach” of the 1977 Additional Protocol I, including violations of Article 57(2)(a)(iii), is a punishable offence.
According to the Report on the Practice of Iraq, the target should not induce the use of excessive force because the possible harm to civilians or undue damage to their possessions might exceed the specific military purpose. On the basis of a press conference given by the President of Iraq in 1980, the report considers that this means acting with only the degree of force necessary to achieve the specific military objective. The aim is to give due regard to humanitarian requirements and to lessen civilian suffering.
Report on the Practice of Iraq, 1998, Chapter 1.5, referring to Press Conference of the President, 10 November 1980, Encyclopedia of the Iraqi-Iranian War, Vol. I, p. 318.
The principle of proportionality applies to every aspect of the conduct of hostilities. … Before launching an attack there is an obligation to assess whether or not the impact on the civilian population is excessive in relation to the concrete and direct military advantage anticipated.
Switzerland, Federal Department of Foreign Affairs, ABC of International Humanitarian Law, 2009, pp. 13–14.
International law requires that, in planning an attack on any military objective, account is taken of certain principles. These include the [principle] … that an attack should not be launched if it can be expected to cause civilian losses which would be disproportionate to the military advantage expected from the attack as a whole.
United Kingdom, House of Lords, Statement by the Minister of State, Foreign and Commonwealth Office, 4 February 1991, Hansard, Vol. 525, Written Answers, col. 37.
Yes, there were such occasions. In particular, when we were experiencing collateral damage, such as it was, and some of the targets were in locations where with any weapon system malfunction severe collateral damage would have resulted inevitably, then there were one or two occasions that I chose not to go against those targets, but they were very few and far between and they were not – and this is the most important issue – in my judgment and in the judgment of the Americans of a critical nature, that is to say, they were not fundamental to the timely achievement of the victory. Had that been the case, then regrettably, irrespective of what collateral damage might have resulted, one would have been responsible and had a responsibility for accepting those targets and for going against them.
United Kingdom, Statement of Air Vice Marshall Wratten, Minutes of Evidence taken before the Defence Committee, 22 May 1991, p. 38, § 274.
Some targets were specifically avoided because the value of destruction of each target was outweighed by the potential risk to nearby civilians or, as in the case of certain archaeological and religious sites, to civilian objects.
The Report on the Practice of Zimbabwe states that the provisions of Article 57 of the 1977 Additional Protocol I would be regarded as customary by Zimbabwe because of its adoption of the Geneva Conventions Amendment Act, which incorporates Additional Protocol I into Zimbabwe’s law and practice.
One type of indiscriminate attack violates the principle of proportionality. The practical application of the principle of distinction requires that those who plan or launch an attack take all feasible precautions to verify that the objectives attacked are neither civilians nor civilian objects, so as to spare civilians as much as possible. Once the military character of a target has been ascertained, commanders must consider whether striking this target is “expected to cause incidental loss of life, injury to civilians, damage to civilian objectives or a combination thereof, which would be excessive in relation to the concrete and direct military advantage anticipated.” If such casualties are expected to result, the attack should not be pursued. The basic obligation to spare civilians and civilian objects as much as possible must guide the attacking party when considering the proportionality of an attack. In determining whether an attack was proportionate it is necessary to examine whether a reasonably well-informed person in the circumstances of the actual perpetrator, making reasonable use of the information available to him or her, could have expected excessive civilian casualties to result from the attack.
When planning actions that could endanger civilian persons and objects, the same extent of care and precautions which are to be taken in the conduct of operations must be also taken at this stage. The precautions comprise respect for the rule of proportionality.
Frédéric de Mulinen, Handbook on the Law of War for Armed Forces, ICRC, Geneva, 1987, §§ 390 and 458.
All the governments concerned replied favourably.
Following NATO’s air campaign in the Federal Republic of Yugoslavia in 1999, Human Rights Watch criticized NATO’s decision to attack the Novi Sad bridge and six other bridges during which civilian deaths occurred. According to Human Rights Watch, these bridges were road bridges and most were urban or town bridges that were not major routes of communications. As a result, “the risk in terms of civilian casualties in attacking urban bridges, or in attacking during daylight hours, is ‘excessive in relation to the concrete and direct military advantage anticipated,’ the standard of proportionality codified in Protocol I, art. 57”.

References: § 556
 § 957
 § 24
 § 417
 § 2
 § 16
 § 2
 § 2
 § 5
 § 13
 § 5
 § 274
 art. 57