This chapter recalls the distinction between responsibility and liability as it emerged in the work of the International Law Commission and its inherent difficulties, before turning to its relevance in relation to the interplay between the obligation to prevent harm and the prohibition to cause harm, the question of cessation and the procedural treatment at the International Court of Justice of the issues of injury, causality and reparation owed. The chapter questions the received wisdom according to which ‘responsibility’ and ‘liability’ would be two different legal genres and argues that the dichotomy between them is porous.

International liability and international criminal law are presented as alternatives to the law of state responsibility. Both regimes have developed out of real-life incidents to which state responsibility has not offered a sufficient enough solution. With their respective focus on adequate compensation and the desire to penalize perpetrators for the most serious violations of international law, they represent qualitatively different approaches to state responsibility. A more limited test of functionality is conducted in order to analyze whether the practical utility of these two regimes is higher than concerning the law of state responsibility. Three criteria that are crucial to a well-functioning and practical responsibility regime are explored: social control, collectivity, and signalling effect. The thematic evaluation of the two responsibility regimes shows that in some respects these particularized regimes fare better than state responsibility while also suffering from problems internal to their particular regimes. The core of the matter is that both regimes have their own rationale from which they do not purport to slide.