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conduct of hostilities
to the enemy’s operational picture, depriving the enemy of them might offer a definite military advantage (Commentary accompanying Rule 79). Some members of the International Group of Experts took the position that cyber infrastructure supporting their transmission qualifies as a military objective, although they cautioned that the infrastructure could only be attacked subject to the Rules regarding attack, especially those on proportionality and precautions in attack (Rules 51 to 58). In particular, they noted that the latter requirement would usually result in an obligation to only mount cyber operations designed to block the broadcasts in question. Other Experts argued that the nexus between the cyber infrastructure and military action is too remote to qualify the infrastructure as a military objective. All members of the International Group of Experts agreed that such assessments are necessarily contextual. 26. An attacker’s assessment that an object is a military objective is made ex ante, that is, in light of the facts as reasonably assessed by the attacker at the time of the decision to attack. For example, if a cyber attack is unsuccessful because effective enemy cyber defences prevent it and the attack yields no military advantage, this does not deprive the object of its character as a military objective.
Rule 39 – Objects used for civilian and military purposes An object used for both civilian and military purposes – including computers, computer networks, and cyber infrastructure – is a military objective. 1. The object and purpose of this Rule is to clarify the issue of ‘dualuse’ objects, since it is often the case that civilian and military users share computers, computer networks, and cyber infrastructure. Any use or future use contributing to military action renders an object a military objective (Rule 38).95 As a matter of law, status as a civilian object and military objective cannot coexist; an object is either one or the other. This principle confirms that all dual-use objects and facilities are military objectives, without qualification.96 2. An attack on a military objective that is also used in part for civilian purposes is subject to the principle of proportionality and the 95
96
Hague Regulations, Art. 27 (protecting civilian buildings ‘provided they are not being used at the time for military purposes’). US Commander’s Handbook, para. 8.3; AMW Manual, commentary accompanying Rule 22(d); ICRC Customary IHL Study, commentary accompanying Rule 8 (noting that status depends on application of the definition of military objective).