Rule 164

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]

  1. 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.
  2. 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]
  3. 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.
  1. 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.”
  2. 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.