The Right to Self-Defence against Non-State Actors: Criteria of the ‘Unwilling or Unable’ Test

Abstract

Some of the States involved in the fight against ISIL in Syria assert that they have a right to individual and/or collective self-defence for two reasons: because ISIL perpetrates armed attacks and because Syria is “unwilling or unable” to prevent the commission of those attacks. The “unwilling or unable” test is not part of contemporary international law. Indeed, State practice remains unclear as to the requirements for the implementation of this test, when it is applied to a State from which a non-State actor commits armed attacks, in the absence of any positive support of that State. This essay aims to present what should be those requirements.

Keywords: Right to Self-Defence, Non-State Actor, Unwilling or Unable Test