(1) (l) “Collateral damage” means incidental loss of civilian life, injury to civilians and damage to civilian objects or other protected objects or a combination thereof, caused by an attack on a lawful target.
- The concept of collateral damage lies at the heart of the principle of proportionality, which prohibits an attack that may be expected to cause collateral damage which would be excessive in relation to the concrete and direct military advantage anticipated to result from the attack (see Rule 14). The definition is drawn from the principle as set forth in Art. 51 (5) (b) of AP/I, Art. 57 (2) (a) (iii) of AP/I and Art. 57 (2) (b) of AP/I.
- There are two categories of collateral damage referred to in Art. 57 of AP/I. One is that of incidental loss or injury to civilians and the other is that of damage to civilian objects. Strictly speaking, collateral damage relates only to the subcategory of damage to civilian objects. However, as used in this Manual, the term collateral damage extends also to the subcategory of incidental loss — or injury to — civilians.
- Two factors underlie the term. First, the loss / injury or damage must be incidental. For instance, civilians or civilian objects that are intentionally or indiscriminately (and unlawfully — see, respectively, Rule 11 and Rule 13) attacked do not constitute collateral damage. Secondly, the death of, or injury to, combatants or civilians directly participating in hostilities does not constitute collateral damage. Similarly, damage to, or destruction of, military objectives (including civilian objects which have become military objectives through location, purpose or use) does not constitute collateral damage. Combatants, military objectives and civilians directly participating in hostilities are lawful targets (see Rule 10 (b)).
- In the context of the law of international armed conflict, harm to civilians and civilian objects that the attacker did not expect is not collateral damage included in proportionality calculations, so long as the lack of expectation of harm was reasonable in the circumstances (see the Commentary on Rule 14). The key question with regard to such harm is whether there is compliance with the requirement to take feasible precautions in attack (see Section G).
- Collateral damage does not include inconvenience, irritation, stress, fear or other intangible effects on the civilian population.
- Art. 51 (5) (b) of AP/I, see fn. 214.
- Art. 57 (2) (a) (iii) of AP/I, see fn. 285.
- Art. 57 (2) (b) of AP/I, see fn. 285.
Categories: Section A: Definitions