International criminal law (“ICL”) is legally plural, not a single unified body of norms. As a whole, trials for international crimes involve a complex dance between international and domestic criminal law, the specificities of which vary markedly from one forum to the next. To date, many excellent scholars have suggested that the resulting doctrinal diversity in ICL should be tolerated and managed under the banner of Legal Pluralism. To our minds, these scholars omit a piece of the puzzle that has major implications for their theory – the law’s history. Neglecting the historical context of the international and national criminal laws that inform ICL leads to (a) the uncritical adoption of criminal law doctrine as a proxy for diverse social, cultural and political values; and (b) in the limited instances where criminal law doctrine does reflect underlying societal values, an overly general assumption that respecting the various embodiments of this law is best for ICL. These oversights result in important normative distortions, with major implications for the field’s self-image, function and legitimacy. In particular, scholars and courts overlook that much criminal law doctrine globally is the result of either a colonial imposition or an “unsuccessful” legal transplant, as well as historical examples where respecting pre-existing doctrinal arrangements undermined the value of postwar trials on any semi-defensible measure. In this Article, we revisit a cross-section of this missing history to contribute to both Legal Pluralism and ICL. For the former, we demonstrate that there is nothing inherently good about Legal Pluralism, and that in some instances, a shift from its descriptive origins into a more prescriptive form risks condoning illegitimate or dysfunctional law. For ICL, our historiography shows how partiality is embedded in the very substance of ICL doctrine, beyond just the politics of its enforcement. At one level, this realization opens up the possibility of renegotiating a universal ICL that, at least in certain circumstances, is actually more plural in terms of values and interests than doctrinal pluralism although the dangers of power masquerading as universalism are also profound. At another, it suggests that institutions capable of trying international crimes need to do far more to step away from the ugly legal histories they have inherited.

Please note: This version of the article is longer than the shorter version we have published with the American Journal of Comparative Law. This longer version includes a fourth part focused on criminal law procedure. In this additional part, we set out the eclectic nature of Argentine criminal procedure as a null hypothesis, since it shows evidence of a congruence between criminal law doctrine and surrounding social values that acts as an exception to the trend we identify in our other examples. We then qualify this Argentine counterexample by discussing the history of employing divergent criminal procedure in post-WWI trials to show instances when ICL must adopt a unified standard for functional reasons. In this longer version, we also weave the insights from these two examples of criminal procedure throughout the remainder of the piece