Rule 10. Civilians Objects’ Loss of Protection from Attack
Rule 10. Civilian objects are protected against attack, unless and for such time as they are military objectives.
Summary
State practice establishes this rule as a norm of customary international law applicable in both international and non-international armed conflicts.
International and non-international armed conflicts
Loss of protection of civilian objects must be read together with the basic rule that only military objectives may be attacked. It follows that when a civilian object is used in such a way that it loses its civilian character and qualifies as a military objective, it is liable to attack. This reasoning can also be found in the Statute of the International Criminal Court, which makes it a war crime to intentionally direct attacks against civilian objects, provided they “are not military objectives”.[1] 
Numerous military manuals contain the rule that civilian objects lose their protection against attack when and for such time as they are military objectives.[2]  In this context, loss of protection of civilian objects is often referred to in terms of objects being “used for military purposes” or of objects being “used for military action”.[3]  These expressions are not incompatible with this rule and, in any case, they are used by States that have accepted the definition of military objectives contained in Rule 8.
Situations of doubt as to the character of an object
The issue of how to classify an object in case of doubt is not entirely clear. Additional Protocol I formulates an answer by providing that “in case of doubt whether an object which is normally dedicated to civilian purposes, such as a place of worship, a house or other dwelling or a school, is being used to make an effective contribution to military action, it shall be presumed not to be so used”.[4]  No reservations have been made to this provision. Indeed, at the Diplomatic Conference leading to the adoption of the Additional Protocols, Mexico stated that Article 52 was so essential that it “cannot be the subject of any reservations whatsoever since these would be inconsistent with the aim and purpose of Protocol I and undermine its basis”.[5]  The principle of presumption of civilian character in case of doubt is also contained in Amended Protocol II to the Convention on Certain Conventional Weapons.[6] 
The presumption of civilian character of an object formulated in Additional Protocol I is also contained in numerous military manuals.[7]  While the US Air Force Pamphlet contains this rule,[8]  a report submitted to Congress by the US Department of Defense in 1992 states that the rule is not customary and is contrary to the traditional law of war because it shifts the burden of determining the precise use of an object from the defender to the attacker, i.e., from the party controlling that object to the party lacking such control. This imbalance would ignore the realities of war in demanding a degree of certainty of the attacker that seldom exists in combat. It would also encourage the defender to ignore its obligations to separate civilians and civilian objects from military objectives.[9]  According to the Report on the Practice of Israel, Israel is of the view that this presumption only applies when the field commander considers that there is a “significant” doubt and not if there is merely a slight possibility of being mistaken. Accordingly, the decision whether or not to attack rests with the field commander who has to determine whether the possibility of mistake is significant enough to warrant not launching the attack.[10] 
In the light of the foregoing, it is clear that, in case of doubt, a careful assessment has to be made under the conditions and restraints governing a particular situation as to whether there are sufficient indications to warrant an attack. It cannot automatically be assumed that any object that appears dubious may be subject to lawful attack. This is also consistent with the requirement to take all feasible precautions in attack, in particular the obligation to verify that objects to be attacked are military objectives liable to attack and not civilian objects (see Rule 16).

[1] ICC Statute, Article 8(2)(b)(ii); see also Article 8(2)(b)(ix) and (e)(iv) (concerning attacks against buildings dedicated to religion, education, art, science or charitable purposes, historic monuments, hospitals and places where the sick and wounded are collected) and Article 8(2)(b)(v) (concerning attacks against towns, villages, dwellings or buildings which are undefended).
[2] See, e.g., the military manuals of Australia (cited in Vol. II, Ch. 2, § 687), Belgium (ibid., § 688), Cameroon (ibid., § 689), Canada (ibid., § 690), Colombia (ibid., § 691), Croatia (ibid., § 692), France (ibid., § 693), Israel (ibid., § 694), Italy (ibid., § 695), Kenya (ibid., § 696), Madagascar (ibid., § 697), Netherlands (ibid., §§ 698–700), New Zealand (ibid., § 701), Russia (ibid., § 702), Spain (ibid., § 703) and United States (ibid., §§ 704–705).
[3] See, e.g., the practice of Australia (ibid., § 687), Canada (ibid., § 690), Netherlands (ibid., § 700), Russian Federation (ibid., § 702) and United States (ibid., §§ 705 and 710–711).
[4] Additional Protocol I, Article 52(3) (adopted by 79 votes in favour, none against and 7 abstentions) (ibid., § 719).
[5] Mexico, Statement at the Diplomatic Conference leading to the adoption of the Additional Protocols (ibid., § 751).
[6] Amended Protocol II to the Convention on Certain Conventional Weapons, Article 3(8)(a) (ibid., § 720).
[7] See, e.g., the military manuals of Argentina (ibid., § 725), Australia (ibid., § 726), Benin (ibid., § 727), Cameroon (ibid., § 728), Canada (ibid., § 729), Colombia (ibid., § 730), Croatia (ibid., § 731), France (ibid., § 732), Germany (ibid., § 733), Hungary (ibid., § 734), Israel (ibid., § 735), Kenya (ibid., § 736), Madagascar (ibid., § 737), Netherlands (ibid., § 738), New Zealand (ibid., § 739), Spain (ibid., § 741), Sweden (ibid., § 742), Togo (ibid., § 743) and United States (ibid., § 744).
[8] United States, Air Force Pamphlet (ibid., § 744).
[9] United States, Department of Defense, Final Report to Congress on the Conduct of the Persian Gulf War (ibid., § 752).
[10] Report on the Practice of Israel (ibid., § 749).