A combined operation is an operation in which two or more States participate on the same side of an international armed conflict, either as members of a permanent alliance or an ad hoc coalition.
[Commentary]
Rule 160 clarifies that combined operations relate to the integration and alignment of the forces of two or more States that are partners in a combined operation, fighting a common enemy in an international armed conflict. It is not important whether this alignment reflects an ad hoc coalition or a permanent alliance (such as NATO). Moreover, Rule 160 applies equally to forces that are integrated — fighting under unified com-mand — and to forces which merely operate in some degree of cooperation against a common enemy.
A State may not invoke its participation in combined operations as justification for its failure to perform its obligations under the law of international armed conflict.
[Commentary]
- Rule 161 refers mainly to non-universal treaties which apply to different sets of Contracting Parties and therefore create different legal regimes. Customary international law is in principle the same for all States (with the exception of a persistent objector), but account must be taken of the fact that the interpretation of specific norms of customary international law may also be subject to divergent views.
- States occasionally undertake, by treaty, obligations that are not binding upon their partners in a combined operation, since the latter have not signed, ratified, or adhered to the same treaty. Absent a si omnes condition in the treaty (i.e. a treaty stipulation that its application is contingent on the condition that all Belligerent Parties are Contracting Parties), a treaty remains binding on Contracting Parties irrespective of whether co-belligerents are also Contracting Parties.
The legal obligations of a State participating in combined operations do not change when its armed forces are operating in a multinational force under the command or control of a military commander of a different nationality.
[Commentary]
- The obligations of any State under international law are based on customary law and on any treaties to which it is a Contracting Party. These obligations do not change when the State participates in a combined operation with States that have different obligations. This is the case even when the commanding officer of the combined operation comes from a State that has different treaty obligations.
- The problem transcends the issue of different treaty obligations undertaken by partners in a combined operation (see Commentary on Rule 161). It is a common phenomenon for States which are Contracting Parties to the same treaty to interpret certain clauses of that treaty in a different way, just as States often differ in their interpretation of customary international law. This would be an issue of legal interoperability (see Rule 164). A good example of the latter phenomenon involves the divergent approaches to the application of the principles pertaining to military objectives (see Section E, especially paragraph 2 of the Commentary on Rule 24). Specifically, two or more partners to a combined operation may have different interpretations of the law of international armed conflict as regards targeting in a manner affecting their respective assessment of the legality of a particular bombing mission. The result may be that one partner in the combined operation may be willing to undertake the mission, whereas another may not. The question that arises is whether the latter State may nevertheless provide the former with escort fighter aircraft, while the bombing itself is conducted by a bomber of the former State.
- One way of resolving such issues is by using common Rules of Engagement as a tool. A State may agree to Rules of Engagement that are more restrictive than its obligations under the law of international armed conflict (as it interprets it), in order to be in harmony with the conduct of partners in the combined operation or for other reasons.
- Another way is to permit partners in the combined operation to insert “caveats” if they find common Rules of Engagement to be too “robust”. This is done before an operation commences or when the common Rules of Engagement of an ongoing combined operation are to be reconsidered. Such caveats may be based on legal, as well as political or other reasons. A partner in the combined operation may find it necessary to put certain restrictions on the operations of its troops, in order to maintain sufficient domestic political support for its participation in the combined operation. Caveats may also be based on reasons that have a technical basis, such as when one partner in the combined operation has less accurate weaponry at its disposal than other partners in the combined operation, and therefore finds it necessary to apply stricter Rules of Engagement for its forces in order to keep the risk of collateral damage at a sufficiently low level.
- Such caveats will give other partners in the combined operation advance notice of a partner’s inability or unwillingness to undertake certain tasks, thus enabling the force commander of the combined operation to adapt plans accordingly. This is typically done by applying a “troops to task” solution, which means that particular tasks are assigned to troops that are not barred from executing them by caveats. In combined operations with many partners and a substantial number of caveats, the commander may use a matrix that shows which troops can be assigned which tasks.
- For reasons of operational efficiency, and in order to keep planning simple and reduce the potential for misunderstandings, force commanders would prefer to have the least possible number of caveats to the common Rules of Engagements from the partners in the combined operation. However, the legal and political constraints may be such that this becomes unavoidable.
- It is up to the partners in a combined operation to decide how to organize the decision-making process. One solution may be to have a collective body, typically with representatives from all partners in the combined operation, undertaking analyses of proportionality and other requirements of the law of international armed conflict and deciding on targeting issues. When such a collective procedure is adopted, each partner to the combined operation may have the power to impose a veto barring any particular attack. The imposition of veto is called “red card” procedure. If a partner in the combined operation “shows the red card” with regard to a particular attack that is being planned, the attack will have to be cancelled.
- Another way to organize the decision-making process may be to vest the authority to make targeting decisions not with the operational commander alone, but allowing partners in the combined operation the use of a “red card” to preclude assignment of particular missions to their respective forces, in accordance with their caveats (see paragraphs 4 − 6 of the Commentary on this Rule) or for other reasons. Under this arrangement, the operational commander may still be able to carry out his plan, but only if he has at his disposal forces that are able and willing to execute it.
A State’s obligations under the law of international armed conflict do not change when its air or missile forces are operating from the territory of a co-belligerent, including when its air or missile forces are operating from the territory of a co- belligerent that has different obligations under the law of international armed conflict.
[Commentary]
- The basis for this Rule is the same as for Rule 162.
- The principle is obvious when an operation takes place in enemy territory, but applies also when the combined operation is conducted in or from a co-belligerent’s territory.
- It must be emphasized that Rule 163 only applies to the “territory of a co-belligerent”. Thus, it is without prejudice to the obligations arising under Section X.
- The specifics of the use of the territory of one co-belligerent by another will depend on an agreement between the two States. This agreement may be either general or ad hoc in character.
- Required consent to operate in or from the territory of a co-belligerent may be subject to restrictions on the visiting force — imposed by the host State — based on the host State’s legal obligations or on other considerations. It depends on the nature of the host State’s legal obligations whether it must insist on particular restrictions affecting the activities of a partner in a combined operation launched from bases in its territory.
A State may participate in combined operations with States that do not share its obligations under the law of international armed conflict although those other States might engage in activities prohibited for the first State.
[Commentary]
- This Rule deals with the issue usually known as “legal interoperability”, and it is based on the general practice of States as it has developed in the past two decades.
- So far, the only treaty law is Art. 21 (3) of the 2008 Dublin Convention on Cluster Munitions: “Notwithstanding the Rules of Article 1 of this Convention and in accordance with international law, States parties, their military personnel or nationals, may engage in military cooperation and operations with States not party to this Convention that might engage in activities prohibited to a State Party.”[762] Art. 21 (3) of the 2008 Convention on Cluster Munitions is in accordance with understandings expressed by several Contracting Parties to the 1997 Ottawa Convention.[763]
- When one co-belligerent has carried out an operation, it is not prohibited for another co-belligerent to exploit the situation that has arisen, although it would have been illegal for the latter to carry out the operation. If, e.g., a minefield has been laid by one partner to a combined operation that is not bound by a treaty provision on the matter, another co-belligerent who is a Contracting Party to the respective treaty may nevertheless deploy its troops taking into consideration the existence of the minefield.
- Art. 1 (“General Obligations and Scope of Application”) of the 2008 Dublin Convention on Cluster Munitions reads: “1. Each State Party undertakes never under any circumstances to (a) Use cluster munitions; (b) Develop, produce, otherwise acquire, stockpile, retain or transfer to anyone, directly or indirectly, cluster munitions; (c) Assist, encourage or induce anyone to engage in any activity prohibited to a State Party under this Convention. (2) Paragraph 1 of this Article applies, mutatis mutandis, to explosive bomblets that are specifically designed to be dispersed or released from dispensers affixed to aircraft. (3) This Convention does not apply to mines.”
- Australia, for example, made the following declaration of understanding upon ratification of the 1997 Ottawa Convention: “It is the understanding of Australia that, in the context of operations, exercises or other military activity authorised by the UN or otherwise conducted in accordance with international law, the participation by the Australian Defence Force, or individual Australian citizens or residents, in such operations, exercises or other military activity conducted in combination with the armed forces of States not party to the Convention which engage in activity prohibited under the Convention would not, by itself, be considered to be in violation of the Convention.” A similar declaration of understanding was made by Canada and the United Kingdom.
