A unitary theory of perpetration is one that does not espouse different legal standards for different forms of participating in crime. In this Article, I pay homage to Professor Damaška’s influence on my work and career by reiterating my earlier arguments for a unitary theory of perpetration in international criminal law. Whereas my earlier work defended the unitary theory in abstract terms then for international criminal law in particular, this Article looks to the history of the unitary theory in five national systems that have abandoned differentiated systems like that currently in force internationally in favor of a unitary variant. Curiously, as things transpire, the reasons Norway, Denmark, Italy, Austria and Brazil dispensed with the types of differentiated system currently in force in international criminal law are strangely familiar to those working in international criminal justice today. The eerie sense of déjà vu that arises from reading these histories suggests that, potentially, the unitary theory may have real potential as a way through many of the key points of conceptual impasse that presently characterize this aspect of the field. In this respect, the Article seeks to contribute an historical perspective to a burgeoning dialogue about forms of blame attribution internationally by again questioning whether the great struggle with “modes of liability” is worth continuing.