Actor-pluralism, the ‘turn to responsibility’ and the jus ad bellum: ‘unwilling or unable’ in context

Abstract

With the increasing (although by no means uniquely modern) phenomenon of unattributable non-state actor (NSA) cross-border violence, a purely inter-state-rights-based approach to Article 51 of the UN Charter is not (if ever indeed it was) sustainable. The jus ad bellum does, and should, reflect broader shifts in general international law. This article argues that (i) the ever-increasing but nevertheless long-standing diversity of actors in modern international law is accommodated within a pluralistic conception of the UN Charter; (ii) the increasingly recognised shift in international law from ‘sovereignty as right’ to ‘sovereignty as responsibility’ is contextually relevant in interpreting the right to use force in self-defence; and that (iii) together, these broader shifts in general international law, as reflected in the jus ad bellum, support and inform the legal basis of a victim state's right to use defensive force in a foreign host state's territory in response to unattributable armed attacks by NSAs, both via the ‘unwilling or unable’ doctrine.