The Use of Force and International Law

INTRODUCTION

While authorisation by the United Nations (UN) Security Council and self-defence are two clear exceptions to the prohibition of the use of force, even if their application is often mired in controversy, it might plausibly be contended that there is a further exception to the prohibition: consent by a state to the forces of another state operating upon its territory. Although on the one hand the coercive nature of the force used under Security Council authorisation or in self-defence remains a violation – albeit, a justified violation – of state sovereignty, a state's use of force upon the territory of another state with its consent, on the other hand, involves no violation of state sovereignty ab initio. If consent to the deployment of military personnel is validly given, there is no use of force against the host state and it should not, therefore, be considered as an exception to the prohibition of the use of force. This appears to be a widely shared view of consent to intervention. It is, for example, the view of the UK that ‘in the case of consent validly given, there is no violation of international law, and therefore no question of wrongfulness should arise’, and it is arguable that ‘the majority of doctrine has come down on this side’.

Yet, this apparently clear position regarding the legality of consent to intervention assumes ‘clarity in the status of actors and the nature of the consent that is often lacking’. Force is employed in these situations most often against non-state actors present and operating within a state's territory, who may be a perceived enemy of either the acting state, the territorial state or both. An invitation was thus provided to the United States and other states by Iraq in 2014 to take action upon its territory in the battle against so-called Islamic State. Yet, what happens in cases where it is not clear which entity represents, or has come to represent, the ‘state’? For example, a full-blown civil war may have become identifiable with both sides controlling a portion of state territory, as was witnessed at times during the Syrian civil war that began in 2011.