There is a lot of misunderstanding about the principle of proportionality. It has to do with minimizing civilian casualties and damage to civilian property; it has nothing to do with equality of arms, nor with comparing the number of casualties on each side. 2 In other words, known broadly, as “the principle that when attacking military objectives belligerents must make sure that any collateral damage to civilians is not out of proportion to the military. The principle of proportionality has also been found by the ICRC to form part of customary international law in international and non-international armed conflicts. It is clear that the Yugoslav Tribunal is of the opinion that (a) a rule of proportionality exists in customary international law and (b) that its formulation is in accordance with that proposed in Protocol I.
Hensel, Howard M., ed. Legitimate Use of Military Force. Abingdon, Oxon, GBR: Ashgate Publishing Group, 2008. ProQuest ebrary. Web. 23 November 2015.
Copyright © 2008. Ashgate Publishing Group. All rights reserved.
The principle of proportionality, as in Rule 14 of the ICRC Rules, is expressed as a rule of prohibition.
Hensel, Howard M., ed. Legitimate Use of Military Force. Abingdon, Oxon, GBR: Ashgate Publishing Group, 2008. ProQuest ebrary. Web. 22 November 2015.
Copyright © 2008. Ashgate Publishing Group. All rights reserved.

Nowadays, customary international law recognizes the principle of proportionality. 47 In the words of Judge Higgins, in her Dissenting Opinion in the NuclearWeapons Advisory Opinion: The principle of proportionality, even if finding no specific mention, is reflected in many provisions of Additional Protocol I to the Geneva Conventions of 1949. Thus even a legitimate target may not be attacked if the collateral civilian casualties would be disproportionate to the specific military gain from the attack. 48 It must be appreciated that a military objective does not cease being a military objective on account of the disproportionate collateral civilian casualties. The principle of proportionality provides ‘a further restriction’ by disallowing attacks against impeccable military objectives owing to anticipated disproportionate injury and damage to civilians or civilian objects. 49
Dinstein, Yoram. Conduct of Hostilities under the Law of International Armed Conflict. West Nyack, NY, USA: Cambridge University Press, 2004. ProQuest ebrary. Web. 22 November 2015.
Copyright © 2004. Cambridge University Press. All rights reserved.
Hensel, Howard M., ed. Legitimate Use of Military Force. Abingdon, Oxon, GBR: Ashgate Publishing Group, 2008. ProQuest ebrary. Web. 22 November 2015.
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Military manuals which are applicable in or have been applied in noninternational armed conflicts specify the principle of proportionality in
attack.19 Many States have adopted legislation making it an offence to violate
the principle of proportionality in attack in any armed conflict.
20 In theMilitary Junta case in 1985, the National Appeals Court of Argentina considered the
principle of proportionality in attack to be part of customary international
law. 21 There are also a number of official statements pertaining to armed conflicts in general or to non-international armed conflicts in particular that refer
to this rule.
22 The pleadings of States before the International Court of Justice
in the Nuclear Weapons case referred to above were couched in general terms
applicable in all armed conflicts.
The jurisprudence of the International Criminal Tribunal for the Former Yugoslavia and a report of the Inter-American Commission on Human
Rights provide further evidence of the customary nature of this rule in non international armed conflicts.
23 No official contrary practice was found with respect to either international or non-international armed conflicts. Alleged violations of the principle of proportionality in attack have generally been condemned by States.
24 The United Nations and other international organisations have also condemned such violations, for example, in the context of the conflicts in Chechnya, Kosovo, the
Middle East and the former Yugoslavia. 25 The ICRC has reminded parties to both international and non-international Armed conflicts of their duty to respect the principle of proportionality in attack. 26

have shown, the obligation to distinguish whether a target is civilian in nature continues to be upheld in instances where combatants are located within the civilian population. These examples demonstrate that the principle of distinction is a necessary component of IHL, as the principle acts as a mechanism for holding violators to account during judicial proceedings. However, as the final section of this paper will argue, in order for this principle to be effective, greater enforcement efforts must be made by the international community to promote compliance with IHL.