This article explores the relationship between John Dugard and Gustav Radbruch. Drawing on the legal philosophy of Gustav Radbruch and John Dugard's work on international criminal law the article addresses the complex question of whether retroactive punishment is legally and morally justifiable. The article discusses Dugard's views on the question of retroactivity in three contexts: firstly, in his opinion on the legality of extraterritorial prosecution of torture in the Bouterse case, secondly, through his criticism of the Constitutional Court's decision in Azapo, and thirdly, by his support for ius cogens norms as expressed in his separate opinion in the Congo v Rwanda decision. The article concludes that Dugard's support for retroactive punishment in the specific context of serious international crimes is another example of his lifelong dedication to 'higher law' and his faith in the normative evolution of international law.