The meaning of treaty authorisation and ad hoc consent for the legality of military assistance on request

ABSTRACT Treaties authorising military assistance serve as an argument for the legality of military presence, deter enemies, prove political integration of states, or support a fragile regime. A treaty should explicitly allow for the sending of troops. In addition, ad hoc consent is needed unless military assistance complies with jus ad bellum. The lack of ad hoc consent despite a clear treaty norm, as well as a lack of assistance despite both the treaty norm and ad hoc request, may amount to a breach of a treaty if the interests of one of the parties were violated by such conduct. The article is divided into three parts, which discuss: the functions of the treaties authorising the military assistance; how consent for the military assistance may be formulated in a treaty; and the form of the ad hoc consent, and the relationship between the ad hoc consent and a treaty.