Related Rule
Netherlands
Practice Relating to Rule 14. Proportionality in Attack
The Military Manual (1993) of the Netherlands states:
During an attack on a military objective, the collateral damage (loss of civilian life and damage to civilian objects) may not be excessive in relation to the military advantage anticipated from the attack. In every combat action, therefore, the commander must assess whether the action is to take place in the proximity of civilians or civilian objects. 
Netherlands, Toepassing Humanitair Oorlogsrecht, Voorschift No. 27-412/1, Koninklijke Landmacht, Ministerie van Defensie, 1993, p. V-5.
The Military Manual (2005) of the Netherlands states that “the humanitarian law of war” limits “military force in order to avoid … unnecessary suffering”. 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, § 0118.
The manual lists “proportionality and subsidiarity” as one of five “generally accepted principles of the humanitarian law of war”. 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, §§ 0221 and 0223; see also § 1028.
The manual further states:
Collateral damage and degree of force used must not be excessive in relation to the expected military advantage. This is known as the principle of proportionality. Proportionality implies that no more force may be used than is strictly necessary to achieve the set purpose. Moreover, no more force must be used than necessary to defeat the enemy. The principle of subsidiarity requires a commanding officer, when choosing from a number of means, to choose that which causes the least collateral damage. The principles of proportionality and subsidiarity are developed further in Chapter 5 (points 0541 ff.) and elsewhere.
During the Second Gulf War, the Iraqi military had placed aircraft in hangars in residential districts. To destroy these aircraft from the air, by indiscriminate bombing, would not have been proportionate. In any case, since the aircraft were in hangars in residential districts, they posed no direct threat, and indiscriminate bombing would undoubtedly have caused (severe) collateral damage to civilian property. 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, § 0229 and p. 33.
[emphasis in original]
In its chapter on behaviour in battle, the manual states that “disproportionate damage to civilian objects and the civilian population caused by attacking military targets must be limited”. 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, § 0504.
The manual also states:
0516. The following attacks are also considered indiscriminate:
- attacks which may be expected to strike the civilian population excessively hard. AP I [1977 Additional Protocol I] describes these as attacks that may be expected to cause collateral loss of life among civilians, damage to civilian objects on a scale that is excessive in relation to the military advantage anticipated.
0517. Put more simply, in an attack on a military objective, the collateral damage (loss of life among the civilian population and damage to civilian objects) must not be disproportionate to the military advantage to be gained by the attack on the military objective. The commanding officer must therefore weigh up, when an action is contemplated near civilians or civilian objects, whether it should take place (proportionality). 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, §§ 0516–0517.
In addition, the manual states: “An attack should not be carried out if it can be expected to cause collateral damage to cultural property on a scale out of proportion to the expected military advantage.” 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, § 0529.
In its chapter on non-international armed conflict, the manual states: “In attacks, the basic principle of proportionality must be central. This imposes an obligation to avoid excessive damage with regard to the civilian population and civilian objects.” 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, § 1035; see also § 1046.
In that same chapter, the manual further states: “Military operations in which civilians or civilian objects may be affected must be carried out with due regard for the principle of proportionality.” 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, § 1054.
In its chapter on peace operations, under the heading “Code of Conduct for the Armed Forces”, the manual states: “Members of the armed forces may be ordered to use force, but must refrain from using it unnecessarily or to excess.” 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, p. 198.
In this chapter, the manual further states:
The RoE [Rules of Engagement] describe the way in which a peace force may use force (and actions classifiable as provocative) and the means to be used to this end. The RoE are based on the principles of proportionality and subsidiarity in the use of force: use no more force than necessary to achieve the purpose, and ensure that no less invasive alternatives are available. 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, § 1218.
In addition, the manual provides: “The use of force to protect goods is (also) always conditional on the principles of legality, necessity and proportionality (often called use of minimum force).” 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, § 1220.
Under the International Crimes Act (2003) of the Netherlands, it is a crime, during an international armed conflict, to commit
the following acts, when they are committed intentionally and in violation of the relevant provisions of Additional Protocol (I) and cause death or serious injury to body or health: … launching an indiscriminate attack affecting the civilian population or civilian objects in the knowledge that such attack will cause excessive loss of life, injury to civilians or damage to civilian objects. 
Netherlands, International Crimes Act, 2003, Article 5(2)(c)(ii).
Likewise, “intentionally launching an attack in the knowledge that such an attack will cause incidental loss of life or injury to civilians or damage to civilian objects … which would be clearly excessive in relation to the concrete and direct overall military advantage anticipated” is also a crime, when committed in an international armed conflict. 
Netherlands, International Crimes Act, 2003, Article 5(5)(b).
In its written statement submitted to the ICJ in the Nuclear Weapons case in 1995, the Netherlands stated: “The general principles of international humanitarian law in armed conflict also apply to the use of nuclear weapons … in particular … the prohibition on attacking military targets if this would cause disproportionate harm to the civilian population”. 
Netherlands, Written statement submitted to the ICJ, Nuclear Weapons case, 16 June 1995, § 32; see also Written statement submitted to the ICJ, Nuclear Weapons (WHO) case, 6 June 1994, § 39.
In 2003, in reply to written questions by Parliament concerning, inter alia, guidelines for aerial bombardment, the Minister of Defence of the Netherlands stated:
The guidelines for target selection during aerial bombardments are based on the relevant provisions of International Humanitarian Law (IHL). Amongst others, all reasonable precautionary measures must be taken to avoid civilian casualties and to prevent collateral damage to civilians objects. In practice, Dutch fighter pilots will not attack targets, when it is likely that civilians will be present. Also, an attack may not be carried out if the collateral damage to be expected reasonably does not relate to the actual and direct military advantage.  
Netherlands, Lower House of Parliament, Statement by the Minister of Defence, Handelingen, 2003–2004 Session, 27 October 2003, Appendix No. 206, pp. 439–440.
The Military Manual (2005) of the Netherlands states: “The relation between collateral damage and the degree of force used on the one hand, and the expected military advantage on the other hand, must not be disproportionate.” 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, p. 34.
At the CDDH, the Netherlands stated that in its view the expression “military advantage anticipated” was intended to refer to “the advantage anticipated from the attack considered as a whole and not only from isolated or particular phases of that attack”. 
Netherlands, Statement at the CDDH, Official Records, Vol. VI, CDDH/SR.41, 26 May 1977, p. 168, § 141 and p. 195.
Upon ratification of the 1977 Additional Protocol I, Netherlands stated that the term “military advantage” as used in the proportionality test of Articles 51 and 57 of the Protocol was understood to refer to the advantage anticipated from the attack considered as a whole and not only from isolated or particular parts of the attack. 
Netherlands, Declarations made upon ratification of the 1977 Additional Protocol I, 26 June 1987, § 5.
The Military Manual (2005) of the Netherlands states:
0511. The circumstances of the time are decisive to whether an object constitutes a military objective. The definition leaves the necessary discretion to the commanding officer. The Dutch Government, in ratifying AP I [1977 Additional Protocol I], has declared in this connection that military commanders who are responsible for carrying out attacks must base their decisions on their evaluation of the information available to them at the time …
0543. When not to attack
An attack should not proceed when an obvious lack of proportion appears to exist between the expected military advantage and the expected collateral damage. The decisive factor is whether a normally alert attacker, in receipt of and acting on due information, could have expected the excessive damage among the civilian population and civilian objects. 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, §§ 0511 and 0543.
At the CDDH, the Netherlands stated:
Commanders and others responsible for planning, deciding upon or executing attacks necessarily had to reach decisions on the basis of their assessment of the information from all sources which was available to them at the relevant time. 
Netherlands, Statement at the CDDH, Official Records, Vol. VI, CDDH/SR.42, 27 May 1977, p. 205, § 1.
Upon ratification of the 1977 Additional Protocol I, the Netherlands declared with regard to Articles 51 to 58 inclusive:
It is the understanding of the Government of the Kingdom of the Netherlands that military commanders and others responsible for planning, deciding upon or executing attacks necessarily have to reach decisions on the basis of their assessment of the information from all sources which is available to them at the relevant time. 
Netherlands, Declarations made upon ratification of the 1977 Additional Protocol I, 26 June 1987, § 6.