By Stephen Riley
In the past few weeks we have witnessed the activation of the crime of aggression as a crime triable by the International Criminal Court (ICC). This formal operationalising of the crime takes place against a wider debate in civil society about the extension of the material jurisdiction of the Court. Alongside its existing material jurisdiction it has been argued that the ICC should try activities like crimes against migrants, environmental crimes, cyberwarfare and other criminal activities of international concern. These are all prima facie candidates for criminal liability and they deserve to be taken seriously as international criminal offences. The intention of this discussion is to separate principle from pragmatism in understanding these as international crimes. I argue that three core principles underlie our international criminal institutions: non injusta lex est, basic standards of humanity, and the idea of a jus gentium. These are natural law principles recognised under international law and support at least some further expansion of the scope of international criminal law.