'Manifestly Failing' and 'Unwilling or Unable' as Intervention Formulas: A Critical Assessment

After 2001, states have increasingly used the “unwilling or unable” formula when justifying military intervention against terrorist targets, such as the United States with respect to targeted killings outside declared theatres of conflict. Moreover, the closely related term “manifestly failing,” serves as a key determinant triggering the international community’s responsibility for protecting vulnerable populations following the third pillar of the responsibility to protect (R2P). Since 2014, the “unwilling and unable” formula has also served as a legal justification for international air strikes against the Islamic State in Syria, despite the Syrian state having declared its willingness to cooperate. Given the formula’s apparent rising prominence, the paper will critically discuss the legal foundations and policy practice of the “unwilling and unable” standard and evaluate what this means for developments of state sovereignty. This examination will relate the formula to other legal justifications for intervening militarily, such as state consent, especially in the context of state disintegration.