Military necessity, along with distinction and proportionality, is one of three key principles of international humanitarian law governing the legal use of force in an armed conflict. Under the principle of military necessity, a decision must be necessary for a legitimate military purpose.
Attacks Military necessity is governed by several constraints: an attack or action must be intended to help in the military defeat of the enemy; it must be an attack on a military objective;Article 52 of Additional Protocol I to the Geneva Conventions provides a widely accepted definition of military objective: "In so far as objects are concerned, military objectives are limited to those objects which by their nature, location, purpose or use make an effective contribution to military action and whose total or partial destruction, capture or neutralization, in the circumstances ruling at the time, offers a definite military advantage" (Source: ). and the harm caused to civilians or civilian property must be proportionate and not "excessive in relation to the concrete and direct military advantage anticipated".Article 51 paragraph 5(b) of Additional Protocol I to the Geneva Conventions.
Luis Moreno-Ocampo was the Chief Prosecutor of the International Criminal Court that investigated allegations of war crimes during the 2003 invasion of Iraq and he published an open letter containing his findings. In a section titled "Allegations concerning War Crimes" he did not call it military necessity but summed up the term:
The judgement of a field commander in battle over military necessity and proportionality is rarely subject to domestic or international legal challenge unless the methods of warfare used by the commander were illegal, as for example was the case with Radislav Krstic who was found guilty as an aider and abettor to genocide by International Criminal Tribunal for the former Yugoslavia for the Srebrenica massacre.
Weapons Military necessity also applies to weapons,Article 35 of the Additional Protocol I to the Geneva Conventions states at the start of PART III that "Basic rules: (1) In any armed conflict, the right of the Parties to the conflict to choose methods or means of warfare is not unlimited. (2) It is prohibited to employ weapons, projectiles and material and methods of warfare of a nature to cause superfluous injury or unnecessary suffering. (3) It is prohibited to employ methods or means of warfare which are intended, or may be expected, to cause widespread, long-term and severe damage to the natural environment." particularly when a new weapon is developed and deployed.Article 36 of the Additional Protocol I to the Geneva Conventions states that "New weapons: In the study, development, acquisition or adoption of a new weapon, means or method of warfare, a High Contracting Party is under an obligation to determine whether its employment would, in some or all circumstances, be prohibited by this Protocol or by any other rule of international law applicable to the High Contracting Party. This usage was considered in Ryuichi Shimoda et al. v. The State (1963):
See also Civilian Combatant Non-combatant Indiscriminate attack Distinction (law) Proportionality (law) Law of war, also referred to as international humanitarian law or the law of armed conflict Civilian casualty ratio Non-combatant casualty value
References . See section "Allegations concerning War Crimes." pp. 4, 5. Ryuichi Shimoda et al. v. The State (1963).
Sources . . .
Footnotes