Source: https://guide-humanitarian-law.org/content/article/3/proportionality/
Timestamp: 2019-04-22 00:10:04+00:00

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Proportionality is a core principle in international law, which provides that the legality of an action shall be determined depending on the respect of the balance between the objective and the means and methods used as well as the consequences of the action. This principle implies an obligation to appreciate the context before deciding on the legality or the illegality of an action. This assessment is the responsibility of those who act. In case of dispute or doubt, tribunals can assess the facts and their legality a posteriori.
Proportionality is particularly important to balance the argument of military necessity in assessing the legality of the use of armed force. Particularly, it applies in cases of individual or collective self-defense, in cases of recourse to armed force by a State to restore order and public safety in times of internal disturbances, and in situations of international or non-international conflicts.
International criminal law also provides that sanctions must be proportionate to the gravity of the crime.
International law does not authorize States to resort to armed force except in cases of self-defense or aggression. The branch of law regulating the right to resort to armed force is commonly referred to as jus ad bellum . Since 1945, it is incorporated in the Charter of the United Nations and its collective security mechanism. But this concept of self-defense only allows measures that are “proportional” to the armed attack and necessary to respond to it.
International humanitarian law applicable to armed conflicts ( jus in bello ) uses the principle of proportionality to limit the damages caused by military operations on civilian population and objects. Once a State has resorted to the use of armed force, jus in bello kicks in to regulate and restrain the use of force in times of armed conflict.
IHL provides that parties to the conflict must distinguish between civilian objects and military objectives, notably by using specific methods of warfare. Nonetheless, the attack of a legitimate target can cause damage on civilian persons and objects protected by IHL. The principle of proportionality complements other IHL principles such as the one of distinction to evaluate the legality of military activities. IHL prohibits attacks that may 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 Arts. 51, 57). The principle of proportionality therefore encompasses different elements in jus ad bellum and jus in bello . In the second case, it goes beyond the proportionality requirement between a military attack and the response to it. It obliges to balance the military advantages sought and the damage and civilian losses related to it. The proportionality requirement also applies to reprisals after an attack. The principle of proportionality is now recognized as a rule of customary law, applicable in both international and non-international armed conflicts (Rule 14 of the 2005 ICRC customary IHL study).
Proportionality is one of the key principles that enables and fosters a concrete debate on the limitations of military action and on the space that must be left for humanitarian operations within situations of conflict. This notion allows certain forms of suffering to be qualified as unnecessary. It does not mean that causing other kinds of harm is acceptable; rather, it reflects the fact that humanitarian law forbids suffering that is caused in no direct relation to a concrete military advantage and in disproportion with it.
The proportional nature of a reprisal in relation to the initial attack is the element that makes the distinction between a reprisal that is acceptable under the law of armed conflict and an act of revenge, which is always prohibited. Humanitarian law clearly establishes the responsibility of military commanders with regard to the respect for this principle.
The Statute of the International Criminal Court (ICC), adopted on 17 July 1998 and entered into force on 1 July 2002, also considers such acts as war crimes and includes them among the crimes over which it has jurisdiction. It adds to this definition the act of “intentionally launching an attack in the knowledge that such attack will cause incidental loss of life or injury to civilians or damage to civilian objects or widespread, long-term and severe damage to the natural environment which would be clearly excessive in relation to the concrete and direct overall military advantage anticipated” (Art. 8.2.b.iv of ICC Statute).
Decisions of international tribunals have specified the content of these obligations (infra Jurisprudence).
The issue of the proportionality of restrictions to human rights imposed by a State in the name of national security or the defense of public order arises in many situations such as internal disturbances or the fight against terrorism, situations in which the intensity of violence does not trigger the application of humanitarian law. International conventions on human rights and national or regional courts are thus in charge of recalling the context and content of the requirement of proportionality in such situations.
From the jurisprudence, it appears that human rights remain applicable in these situations, subject to derogations made by States in accordance with the procedures provided for this purpose. Jurisprudence also states that in these circumstances, decisions made by the executive power remain subject to the control of national and international judges. The latter retain the final authority and responsibility to evaluate the adequacy and proportionality between the restriction of individual rights and the argument of “necessity” used by the government to justify its actions (infra Jurisprudence).
Proportionality is also used in reference to fundamental judicial guarantees, ensuring that the punishment is proportionate to the crime. This is reflected in the Geneva Conventions, which establish that “the courts [of the occupying power] shall apply . . . the principle that the penalty shall be proportioned to the offence” (GCIV Art. 67).
ICJ recalled that “self-defense […] warrant[s] only measures which are proportional to the armed attack and necessary to respond to it, a rule well established in customary international law” ( Military and Paramilitary Activities in and against Nicaragua [ Nicaragua v. United States of America ], Merits, Judgment, ICJ Reports 1984, p. 14, para. 176).
In the ICJ judgment of 1996 on the legality of the use of nuclear weapons, Judge Higgins held that “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” ( Legality of the Threat or Use of Nuclear Weapons , Advisory Opinion, ICJ Reports 1996, p. 226, Separate Opinion of Judge Higgins, p. 587).
According to the ICTY, the principle of proportionality means that incidental and involuntary damages caused to the civilian population during a military attack shall not be excessive in comparison to the direct military advantage obtained.
International law contains a general principle prescribing that reasonable care must be taken in attacking military objectives so that civilians are not needlessly injured through carelessness. Attacks, even when they are directed against legitimate military targets, are unlawful if conducted using indiscriminate means or methods of warfare, or in such a way as to cause indiscriminate damage to civilians ( Kupreskic Case , ICTY Trial Chamber, 14 January 2000, para. 524). In the Kupreskic Case , the Trial Chamber considered that it was beyond dispute that, at a minimum, large numbers of civilian casualties would have been interspersed among the combatants. It continued: “The point which needs to be emphasized is the sacrosanct character of the duty to protect civilians, which entails, amongst other things, the absolute character of the prohibition of reprisals against civilian populations.” Even if it could be proved that the population was not entirely civilian but comprised some armed elements, still no justification would exist for widespread and indiscriminate attacks against civilians. Indeed, even in a situation of full-scale armed conflict, certain fundamental norms still serve to unambiguously outlaw such conduct, such as rules pertaining to proportionality (para. 513). The judges declared that: “In the case of attacks on military objectives causing damage to civilians, international law contains a general principle prescribing that reasonable care must be taken in attacking military objectives so that civilians are not needlessly injured through carelessness” (para. 524). They further recalled that these principles have to some extent been spelled out in Articles 57 and 58 of the First Additional Protocol of 1977. Such provisions, it would seem, are now part of customary international law, not only because they specify and flesh out general pre-existing norms, but also because they do not appear to be contested by any State, including those that have not ratified the Protocol. Admittedly, even these two provisions leave a wide margin of discretion to belligerents by using language that might be regarded as leaving the last word to the attacking party. Nevertheless, this is an area where the “elementary considerations of humanity” should be fully used when interpreting and applying loose international rules, on the basis that they are illustrative of a general principle of international law (para. 524).
What are the relative values to be assigned to the military advantage gained and the injury to non-combatants and/or the damage to civilian objects?
What do you include or exclude in totaling these sums?
What is the standard of measurement in time or space?
To what extent is a military commander obligated to expose his own forces to danger in order to limit civilian casualties or damage to civilian objects? ( 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. 49; available at http://www.un.org/icty/pressreal/nato061300.htm ).
In its judgment in the case of Aksoy v. Turkey , the ECHR recalled that “it falls to each Contracting State, with its responsibility for ‘the life of [its] nation,’ to determine whether that life is threatened by a ‘public emergency’ and, if so, how far it is necessary to go in attempting to overcome the emergency. . . . Nonetheless, Contracting Parties do not enjoy an unlimited discretion. It is for the Court to rule whether, inter alia, the States have gone beyond the ‘extent strictly required by the exigencies’ of the crisis.” Consequently, the derogative measures must be strictly required by the exigencies of the situation ( Aksoy v. Turkey , Application no. 21987/93, Judgment [Chamber], 18 December 1996, para. 68).
In its judgment of 1988, the Inter-American Court for Human Rights affirmed that “regardless of the seriousness of certain actions and the culpability of the perpetrators of certain crimes, the power of the State is not unlimited, nor may the State resort to any means to attain its ends” ( Velasquez Rodriguez v. Honduras , I/A Court H.R. [Ser. C.], no. 4, 1, 1988, para. 154).
In a judgment of 1999 concerning the examination of the legality of using exceptional methods of interrogation in the context of the fight against terrorism, the Israel Supreme Court affirmed that neither international law nor national law recognized the argument of “necessity defence” to resort to torture or physical means during interrogations in the context of the fight against terrorism. The Court was of the opinion that this argument cannot authorize the use of physical means to allow investigators to execute their duties in circumstances of necessity. The Court affirmed that general directives governing the use of physical means during interrogations must be rooted in an authorization prescribed by law and not in defenses to criminal liability. The “necessity” defense cannot constitute an “ex-ante” basis for rules regarding an interrogation ( Public Committee against Torture in Israel v. the Government of Israel , HCJ 5100/94, 26 May 1999, paras. 36–37).
In a judgment of 2004 concerning the examination of the legality of the intervention of the Israel armed forces in Rafah (Gaza Strip), the Israel Supreme Court recognized that the argument of “necessity” can justify a military operation, but recalled that such a military operation can be legitimate from a military point of view but still be unlawful. The Court affirmed that judges have to examine the legality of military operations through the lens of the proportionality principle.
For Additional Information: Amnesty International. “Collateral Damage” or Unlawful Killings? Violations of the Laws of War by NATO during Operation Allied Force . Available at http://www.amnesty.org/ailib/intcam/kosovo .
Cannizzaro, Enzo. “Contextualizing Proportionality: Jus ad Bellum and Jus in Bello in the Lebanese War.” International Review of the Red Cross 864 (December 2006): 779–92.
Dinstein, Yoram. “Collateral Damage and the Principle of Proportionality.” In New Wars, New Laws? , edited by David Wippman and Matthew Evangelista, 211–24. New York: Transnational, 2005.
Henckaerts, Jean-Marie, and Louise Doswald-Beck, ed. Customary International Law . Vol. 1, The Rules . Cambridge: Cambridge University Press, 2005, part 1, chap. 4.
ICTY. Final Report to the Prosecutor by the Committee Established to Review the NATO Bombing Campaign against the Federal Republic of Yugoslavia. Available at http://www.un.org/icty/pressreal/ato061300.htm .
Jaworski, Eric. “Military Necessity and Civilian Immunity: Where Is the Balance?” In International Crime and Punishment, Selected Issues , edited by Sienho Yee, 2:87–127. Lanham, MD: University Press of America, 2004.
John-Hopkins, Michael. “Regulating the Conduct of Urban Warfare: Lessons from Contemporary Asymmetric Armed Conflicts.” International Review of the Red Cross 878 (June 2010): 469–93.
Mulinen, Frederic de. Handbook on the Law of War for Armed Forced . Geneva: ICRC, 1989.

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