Distinction (principle of distinction) is a principle under international humanitarian law governing the legal use of force in an armed conflict, whereby belligerents are required to distinguish between combatants and protected civilians. [1] Combatant in this instance means persons entitled to directly participate in hostilities and thus are not afforded immunity from being directly targeted in situations of armed conflict. [2] Protected civilian in this instance means civilians who are enemy nationals or neutral citizens outside of the territory of a belligerent power. [3] Distinction, proportionality, and precaution are important factors in assessing military necessity in that the harm caused to protected civilians or civilian property must be proportional and not "excessive in relation to the concrete and direct military advantage anticipated" by an attack on a military objective. [4]
The International Court of Justice, in its 1996 Advisory Opinion on Legality of the Threat or Use of Nuclear Weapons, recognized the principle of distinction—between combatants and non-combatants (civilians)—as a fundamental and “intransgressible” principle of customary international law.
The principle of distinction is set forth in Article 48 of Protocol Additional I of 1977 to the 1949 Geneva Conventions for the Protection of War Victims, entitled “Basic rule”: “the Parties to the conflict shall at all times distinguish between the civilian population and combatants and between civilian objects and military objectives and accordingly shall direct their operations only against military objectives." [5] Other provisions of Additional Protocol I further outline the requirement of distinction: Article 50 of defines who is a civilian and what is a civilian population; Article 51 describes the protection which should be given to civilian populations; Chapter III regulates the protection of civilian objects. Article 51(3) of Protocol I explains that “civilians shall enjoy the protection afforded by this section, unless and for such time as they take a direct part in hostilities.” [6]
Article 8(2)(b)(i) of the Rome Statute of the International Criminal Court also prohibits attack directed against civilians. Not all states have ratified Protocol I or the Rome Statute, but it is an accepted principle of international humanitarian law, or IHL, that the direct targeting of civilians is a breach of the customary laws of war and is binding on all belligerents.
Luis Moreno-Ocampo was the Chief Prosecutor of the International Criminal Court who investigated allegations of war crimes during the 2003 invasion of Iraq. He published an open letter containing his findings, in a section titled "Allegations concerning War Crimes,” he elucidates this use of distinction:
Under international humanitarian law and the Rome Statute, the death of civilians during an armed conflict, no matter how grave and regrettable, does not in itself constitute a war crime. International humanitarian law and the Rome Statute permit belligerents to carry out proportionate attacks against military objectives, [4] even when it is known that some civilian deaths or injuries will occur. A crime occurs if there is an intentional attack directed against civilians (principle of distinction) (Article 8(2)(b)(i)) or an attack is launched on a military objective in the knowledge that the incidental civilian injuries would be clearly excessive in relation to the anticipated military advantage (principle of proportionality) (Article 8(2)(b)(iv)).
Article 8(2)(b)(iv) criminalizes:
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;
Article 8(2)(b)(iv) draws on the principles in Article 51(5)(b) of the 1977 Additional Protocol I to the 1949 Geneva Conventions, but restricts the criminal prohibition to cases that are “clearly" excessive. The application of Article 8(2)(b)(iv) requires, inter alia , an assessment of:
(a) the anticipated civilian damage or injury;
(b) the anticipated military advantage;
(c) and whether (a) was "clearly excessive" in relation to (b). [7]
In order to ensure respect for and protection of the civilian population and civilian objects, the Parties to the conflict shall at all times distinguish between the civilian population and combatants and between civilian objects and military objectives and accordingly shall direct their operations only against military objectives. [8]
Persons protected by the Convention are those who, at a given moment and in any manner whatsoever, find themselves, in case of a conflict or occupation, in the hands of a Party to the conflict or Occupying Power of which they are not nationals … Nationals of a neutral State who find themselves in the territory of a belligerent State, and nationals of a [Co-belligerence|co-belligerent] State, shall not be regarded as protected persons while the State of which they are nationals has normal diplomatic representation in the State in whose hands they are.