The use of force in self-defence against non-state actors in the territory of another state not having effective control over activities of non-state actors is subject of numerous controversies. ...While the traditional approach limits the use of force in self-defence from Article 51 of the UN Charter to the inter-state relations, the ever-present threat of international terrorism triggered new trends in expanding the notion of self-defence to private armed attacks. In the past, countries justified their use of force against non-state actors on the territory of another state by attributing the attack to the host state. However, in the last few years, especially in the context of fight against ISIL in Syria, an unwilling or unable host state doctrine received an unprecedented attention. The authors of the paper present prevailing legal arguments for the use of force against non-state actors and assess whether a wider understanding of Article 51 of the UN Charter has emerged.
The existence of an inherent right to self-defense in international law is nowadays undisputed and has long been a part of customary international law. It represents one of the exceptions to the ...prohibition of the use of force and the only legal justification for the unilateral use of force in contemporary international community. Against this background self-defense has become a focal point for the discourse on the lawfulness of the use of force in international law and is gaining new dimensions due to the ever so present threat of global terrorism. Here, Korosec and Veber analyze legal interpretation of an 'armed attack' from Article 51 of the UN Charter, in particular the source of such attack and corresponding rules for attribution, as well as the role the "unwilling or unable" doctrine has started to play in this context. While bearing in mind all relevant instances of the use of self-defense as reactions to terrorist attacks, the situation in Syria is in the center of attention as a possible 'game changer' when it comes to the legality of the use of self-defense against non-state actors positioned on the territory of another state.
