Assessing flag state performance in legal terms: Clarifications of the margin of discretion

A lack of control by flag states over their ships is one of the main causes of the current crisis in oceans management. To address this, the international community has been developing actions against irresponsible flag states in various sectors. However, it is not always clear under what circumstances they are considered to be in breach of their duties. A clarification of this issue will enable the international community to better address this problem by establishing a clear common understanding of what the breach of flag state duties entails. The present article examines this issue by considering the margin of discretion, which is akin to the concept 'margin of appreciation' often used in other areas, such as human rights, enjoyed by flag states in discharging their duties and analyzing the circumstances under which acts of private ships lead to the international responsibility of their flag state for their wrongful acts.