Rule 22. Principle of Precautions against the Effects of Attacks
Rule 22. The parties to the conflict must take all feasible precautions to protect the civilian population and civilian objects under their control against the effects of attacks.
Summary
State practice establishes this rule as a norm of customary international law applicable in both international and non-international armed conflicts. This is a basic rule to which more content is given by the specific obligations contained in Rules 23–24. The practice collected in terms of those specific obligations is also relevant to prove the existence of this rule and vice versa.
International armed conflicts
The duty of each party to the conflict to take all feasible precautions to protect the civilian population and civilian objects under its control against the effects of attacks is set forth in Article 58(c) of Additional Protocol I, to which no reservations have been made.[1] 
Numerous military manuals restate the duty of parties to the conflict to take all feasible precautions to protect the civilian population and civilian objects under their control against the effects of attacks.[2]  This obligation is supported by official statements and reported practice.[3]  This practice includes that of States not, or not at the time, party to Additional Protocol I.[4] 
Non-international armed conflicts
The obligation to take all feasible precautions to protect the civilian population and civilian objects against the effects of attacks was included in the draft of Additional Protocol II but was dropped at the last moment as part of a package aimed at the adoption of a simplified text.[5]  As a result, Additional Protocol II does not explicitly require precautions against the effects of attack. Article 13(1) requires that “the civilian population and individual civilians shall enjoy general protection against the dangers arising from military operations”.[6]  It would be difficult to comply with this requirement without taking precautions against the effects of attack. The requirement to take precautions against the effects of attacks has, moreover, been included in more recent treaty law applicable in non-international armed conflicts, namely the Second Protocol to the Hague Convention for the Protection of Cultural Property.[7]  In addition, this rule is contained in other instruments pertaining also to non-international armed conflicts.[8] 
Military manuals which are applicable in or have been applied in non-international armed conflicts specify the requirement to take precautions against the effects of attacks.[9]  It is supported by reported practice.[10] 
In 1965, the 20th International Conference of the Red Cross adopted a resolution calling on governments and other authorities responsible for action in all armed conflicts to spare the civilian population as much as possible.[11]  This was reaffirmed by the UN General Assembly in a resolution on respect for human rights in armed conflict adopted in 1968.[12]  In addition, in a resolution adopted in 1970 on basic principles for the protection of civilian populations in armed conflicts, the UN General Assembly required that “in the conduct of military operations, every effort should be made to spare civilian populations from the ravages of war, and all necessary precautions should be taken to avoid injury, loss or damage to civilian populations”.[13] 
The jurisprudence of the International Criminal Tribunal for the Former Yugoslavia in the Kupreškić case provides further evidence of the customary nature of the requirement to take precautions against the effects of attacks in both international and non-international armed conflicts. In its judgment, the Tribunal considered that this rule was customary because it specified and fleshed out general pre-existing norms.[14]  It can be argued indeed that the principle of distinction (see Rules 1 and 7), which is customary in international and non-international armed conflicts, inherently requires respect for this rule. The Tribunal also relied on the fact that this rule had not been contested by any State.[15]  This study found no official contrary practice either.
This practice should be read together with the extensive practice on the prohibition of the use of human shields (see Rule 97). The deliberate violation of the obligation to take all feasible precautions against the effects of attacks is often related to the use of human shields. In addition, international case-law has confirmed the obligation under international human rights law to take positive steps to protect life (see commentary to Rule 97).
Examples of precautions against the effects of attacks
Specific examples of how the general obligation to take precautions against the effects of attacks has been implemented include first and foremost the two specific obligations identified in Rules 23 and 24 below.
In addition, practice has shown that the construction of shelters, digging of trenches, distribution of information and warnings, withdrawal of the civilian population to safe places, direction of traffic, guarding of civilian property and the mobilization of civil defence organizations are measures that can be taken to spare the civilian population and civilian objects under the control of a party to the conflict.
Feasibility of precautions against the effects of attack
The obligation to take precautions against the effects of attacks “to the extent feasible” has been interpreted by many States as meaning that the obligation is limited to those precautions which are practicable or practically possible, taking into account all circumstances ruling at the time, including humanitarian and military considerations.[16]  The Rapporteur of the Working Group at the Diplomatic Conference leading to the adoption of the Additional Protocols reported that after the phrase “to the maximum extent feasible” had been introduced to qualify all subparagraphs of Article 58, agreement was quickly reached.[17]  According to the Rapporteur, this revision reflected the concern of small and densely populated countries which would find it difficult to separate civilians and civilian objects from military objectives and that even large countries would find such separation difficult or impossible to arrange in many cases.[18]  Upon ratification of Additional Protocol I, Austria and Switzerland stated that the obligation would be applied subject to the requirements of the defence of the national territory.[19] 
State practice indicates that an attacker is not prevented from attacking military objectives if the defender fails to take appropriate precautions or deliberately uses civilians to shield military operations. The attacker remains bound in all circumstances, however, to take appropriate precautions in attack (see Rule 15) and must respect the principle of proportionality (see Rule 14) even though the defender violates international humanitarian law.
Information required for deciding upon precautions against the effects of attack
Numerous States have indicated that military commanders have to reach decisions concerning the taking of precautions against the effects of attack on the basis of their assessment of the information from all sources which is available to them at the relevant time.[20] 

[1] Additional Protocol I, Article 58(c) (adopted by 80 votes in favour, none against and 8 abstentions) (cited in Vol. II, Ch. 6, § 1).
[2] See, e.g., the military manuals of Argentina (ibid., § 9), Cameroon (ibid., § 11), Canada (ibid., § 12), Croatia (ibid., § 13), Germany (ibid., § 14), Italy (ibid., § 15), Kenya (ibid., § 16), Madagascar (ibid., § 17), Netherlands (ibid., § 18), New Zealand (ibid., § 19), Nigeria (ibid., § 20), Russian Federation (ibid., § 21), Spain (ibid., § 22), Sweden (ibid., § 23) and United States (ibid., § 25).
[3] See, e.g., the statements of Germany (ibid., § 31), Iraq (ibid., § 34) and United States (ibid., § 40) and the reported practice of the Islamic Republic of Iran (ibid., § 33), Malaysia (ibid., § 36), Syrian Arab Republic (ibid., § 39) and Zimbabwe (ibid., § 41).
[4] See, e.g., the practice of Iraq (ibid., § 34), Kenya (ibid., § 16) and United States (ibid., §§ 25 and 40) and the reported practice of the Islamic Republic of Iran (ibid., § 33) and Malaysia (ibid., § 36).
[5] Draft Additional Protocol II submitted by the ICRC to the International Conference leading to the adoption of the Additional Protocols, Article 24(2) (ibid., § 3).
[6] Additional Protocol II, Article 13(1) (adopted by consensus) (ibid., § 2).
[7] Second Protocol to the Hague Convention for the Protection of Cultural Property, Article 8 (cited in Vol. II, Ch. 12, § 290).
[8] See, e.g., Memorandum of Understanding on the Application of IHL between Croatia and the Socialist Federal Republic of Yugoslavia, § 6 (cited in Vol. II, Ch. 6, § 5); Agreement on the Application of IHL between the Parties to the Conflict in Bosnia and Herzegovina, § 2.5 (ibid., § 6); CSCE Code of Conduct, § 36 (ibid., § 7); UN Secretary-General’s Bulletin, Section 5.4 (ibid., § 8).
[9] See, e.g., the military manuals of Croatia (ibid., § 13), Germany (ibid., § 14), Italy (ibid., § 15), Kenya (ibid., § 16), Madagascar (ibid., § 17) and Nigeria (ibid., § 20).
[10] See, e.g., the reported practice of Algeria (ibid., § 30) and Malaysia (ibid., § 36).
[11] 20th International Conference of the Red Cross, Res. XXVIII (ibid., § 45).
[12] UN General Assembly, Res. 2444 (XXIII) (adopted by unanimous vote of 111 votes in favour, none against and no abstentions) (ibid., § 42).
[13] UN General Assembly, Res. 2675 (XXV) (adopted by 109 votes in favour, none against and 8 abstentions) (ibid., § 43).
[14] ICTY, Kupreškić case, Judgment (ibid., § 46).
[15] ICTY, Kupreškić case, Judgment (ibid., § 46).
[16] See the statements of Algeria (ibid., § 49), Belgium (ibid., § 49), Cameroon (ibid., § 56), Canada (ibid., §§ 49 and 57), France (ibid., § 49), Germany (ibid., §§ 49 and 58), Ireland (ibid., § 49), Italy (ibid., §§ 49 and 59), Netherlands (ibid., §§ 49 and 60), Spain (ibid., § 49), United Kingdom (ibid., §§ 49 and 61) and United States (ibid., § 62).
[17] Diplomatic Conference leading to the adoption of the Additional Protocols, Report to Committee III on the Work of the Working Group (ibid., § 65).
[18] Diplomatic Conference leading to the adoption of the Additional Protocols, Report to Committee III on the Work of the Working Group (ibid., § 65).
[19] Austria, Reservations made upon ratification of Additional Protocol I (ibid., § 50); Switzerland, Reservations made upon ratification of Additional Protocol I (ibid., § 51).
[20] See Ch. 4, footnote 33.