Principle of Distinction in International Humanitarian Law

The principle of distinction requires parties to an armed conflict to distinguish lawful targets from protected persons and objects. Operations may be directed only against combatants and military objectives, and not against civilians or civilian objects. The rule is recognised as customary international humanitarian law in international and non-international armed conflicts.

Core requirements

Distinction governs both target selection and the conduct of attacks. Indiscriminate attacks are prohibited because they are not directed at a specific military objective, or their effects cannot be limited as international humanitarian law requires.

• Attacks must not intentionally target civilians or the civilian population.
• A civilian is protected against direct attack unless, and only for such time as, the civilian directly participates in hostilities.
• Under Article 50(1) of Additional Protocol I, a person must be considered a civilian where doubt exists.

Military objectives and dual-use objects

Under Article 52(2) of Additional Protocol I, an object is a military objective only when it effectively contributes to military action by its nature, location, purpose or use, and its total or partial destruction, capture or neutralisation offers a definite military advantage in the circumstances ruling at the time.

• A dual-use object, serving both civilian and military functions, may be attacked only when this two-part definition is satisfied.
• Dual-use character does not automatically make an object a military objective; its actual circumstances must be assessed for each attack.
• Under Article 52(3), doubt about whether an object normally devoted to civilian purposes is being used for military action requires a presumption that it is not so used.

Constraints on an otherwise lawful target

Even when a dual-use object qualifies as a military objective, attacking it remains subject to proportionality and precautions in attack. Parties must verify the target, choose feasible means and methods to reduce civilian harm, and cancel or suspend the attack if its unlawfulness becomes apparent.

• An attack is prohibited if expected incidental civilian harm would be excessive in relation to the concrete and direct military advantage anticipated.
• Civilian presence does not remove the continuing duty to distinguish lawful targets from protected persons and objects.
• Distinction does not prohibit every incidental civilian injury, but deliberate attacks on civilians remain unlawful.