Contemporary international criminal law is largely concerned with holding individual defendants responsible for mass atrocities. Because the crimes usually involve the concerted efforts of many individuals, allocating responsibility among those individuals is of critical importance. This Article examines two liability doctrines – joint criminal enterprise and command responsibility – that play a central role in that allocation of guilt in international criminal tribunals. The Article posits a general framework for understanding the development of international criminal law, as an outgrowth of three legal traditions: domestic criminal law, international human rights law, and transitional justice. We explore the application of that framework to the joint criminal enterprise and command responsibility doctrines and argue that viewing joint criminal enterprise and command responsibility through the lens of our framework shows the need for certain doctrinal reforms. Finally, we discuss the application of liability doctrines developed in the context of inter-national criminal tribunals to prosecutions for international or transnational crimes in other fo-rums, such as domestic military tribunal prosecutions of terrorists, that do not share the same roots as international criminal law.