Chapter 5 offers new insights into the drafting of the criminal responsibility rules in the Rome Statute. Specifically, the chapter argues that it would be simplistic to present the restrained approach to the assessment of criminal responsibility exhibited in the Rome Statute as the triumph of sovereign states, seeking to shield their nationals from convictions, over non-state actors, such as legal scholars, and non-governmental organizations, aiming to expand the scope of criminal responsibility provisions to enable easier convictions for the perpetrators of mass atrocities. In fact, authoritative legal experts were among the most ardent proponents of the proposal to codify in detail the general principles of criminal responsibility in the RS, instead of granting discretion to the future judges at the Court to develop the rules of criminal responsibility. From the perspective of those legal experts, the inclusion of a ‘General Part’ in the Statute marked the progress that ICL had made since its early days towards a coherent penal system. Thus, the politics of the legal field, that is, the promotion and contestations of different understandings of the law, are crucial for understanding how the principled approach to criminal responsibility became influential in Rome.