Crimen Sine Lege: Judicial Lawmaking at the Intersection of Law and Morals

One of the most fundamental defenses to a criminal prosecution is that of nullum crimen sine lege, nulla poena sine lege ("no crime without law, no punishment without law") (NCSL). Notwithstanding that respect for NCSL is a hallmark of modern national legal systems and a recurrent refrain in the omnibus human rights instruments, international criminal law (ICL) fails to fully implement this principle. The absence of a rigorous manifestation of NCSL within ICL can be traced to the dawn of the field with the innovations employed by the architects of the Nuremberg and Tokyo Tribunals. In the face of NCSL defenses, the judges of the Nuremberg Tribunal, in reasoning that was to be later echoed by their brethren on the Tokyo Tribunal, rejected the defense through a complex interplay of arguments about immorality, illegality, and criminality. These core arguments have been adapted to the modern ICL jurisprudence. Where states failed to enact comprehensive ICL in the postwar period, ICL judges have engaged in a full-scale - if unacknowledged - refashioning of ICL through jurisprudence addressed to their own jurisdiction, the elements of international crimes, and applicable forms of responsibility. Along the way, courts have updated and expanded historical treaties and customary rules, upset arrangements carefully negotiated between states, rejected political compromises made by states during multilateral drafting conferences, and added content to vaguely worded provisions that were conceived more as retrospective condemnations of past horrors than as detailed codes for prospective penal enforcement. A taxonomy of these analytical claims reveals the varied ways that today?s ICL defendants have been made subject to new or expanded criminal law rules. Collectively, these cases have the potential to raise acute concerns about whether the rights of defendants are adequately protected in ICL. This, in turn, raises important questions about the legitimacy of ICL as a field of criminal law. This Article argues that the methodology developed by the European Court of Human Rights to enforce the articulation of the NCSL principle in its constitutive document (the European Convention for the Protection of Human Rights and Fundamental Freedoms) suggests that the NCSL jurisprudence has not compromised the fundamental fairness of ICL. Rather, even where new standards have been applied to past conduct, these cases have not infringed the higher order principles underlying the NCSL prohibition.Today's defendants were on sufficient notice of the foreseeability of ICL jurisprudential innovations in light of extant domestic penal law, universal moral values expressed in international human rights law, developments in international humanitarian law and the circumstances in which it has been invoked, and other dramatic changes to the international order and to international law brought about in the postwar period. As a prescriptive contribution, this Article argues that any lingering concerns about the rights of the defendants can and should be mitigated by sentencing practices - to a certain extent already in place and employed by the ad hoc criminal tribunals - that are closely tethered to extant domestic sentencing rules governing analogous domestic crimes.Although focused on the NCSL jurisprudence, this Article also presents a model of ICL formation and evolution that finds resonance in the origins and gradual demise of the common law crime in the United States and elsewhere. Common law crimes provided much of the substantive content for the nascent Anglo-American criminal justice system until they were gradually supplanted by legislative efforts. So too in ICL; common law international crimes have been crucial to building the infrastructure of a truly international criminal justice system. As in the domestic historical narrative, international crimes are increasingly finding expression in more positivistic sources of law, thus obviating the need for, and diminishing the discretion of, international judges to make law in the face of gaps or deficiencies. Collectively, the NCSL cases thus provide insight into the dynamics of ICL argumentation, the interpretive attitudes of ICL judges, and an emerging philosophy of the nature of ICL.