At first sight, securing consent for outside military operations is an attractive argument inasmuch as it appears to make such interventions incontrovertibly lawful. As the text of Article 2(4) of the 1945 Charter of the United Nations indicates, the prohibition of the use of force relates only to military interventions conducted by one state against another state. 1 If we argue a contrario, an operation conducted with the consent of the state in question is not prohibited under the Charter insofar as it is not an infringement on any state's political independence or sovereignty. 2 Accordingly, there would be no need for one state to justify or excuse any such intervention at the invitation of another state. Under the classical conception of international law, a state is represented by its government, and if that government invites another state to intervene in its territory, then such action is in the area of cooperation. 3 The effects of consent are therefore decisive: they tip the situation out of the domain of the use of force and into the domain of friendly relations.The existence of an invitation may also make it possible to escape the intricate debates that beset other aspects of ius contra bellum. This is a familiar point. For example, controversy has arisen -especially in recent years -over the possibility of invoking self-defence when interpreting the meaning of Article 51 of the UN Charter with respect to non-state groups.
1The ´odore Christakis and Karine Bannelier, 'Volenti non fit injuria? Les effets du consentement a `l'intervention militaire', Annuaire franc ¸ais de droit international 50 (2004), 102-37 (112-13). 2 James Crawford, Second Report on State Responsibility, 30 April 1999, UN Doc. A/CN.4/498/ Add.2, 12-13, para. 240(b). 3 See, e.g., UN Security Council (UN SC) Resolution 387 of 31 March 1976, recalling 'the inherent and lawful right of every State, in the exercise of its sovereignty, to request assistance from any other State or group of States'.