International criminal justice claims to challenge the very fundamentals of the international legal order. Yet international criminal justice is also still very much a work in progress. It success will depend on how well it can deal with its great founding dilemmas, while respecting international law and its continuity. No question seems more central yet more ambiguous to international criminal tribunals' existence, in this context, than how they relate to domestic courts. This is an issue which in fact raises anew the very conundrum at the heart of international criminal tribunals' creation and identity. On the one hand, international criminal tribunals can be seen from a universalist perspective which argues that they are first and foremost about the emergence of a global public order; on the other hand, they can be conceived from a sovereignist angle, which sees their prime duty as working for the benefit of states whose crimes they are judging. It is by putting this problematic relationship back into its overall evolution and, in particular, by focusing on what a non-functioning domestic court is under international law, that it will become possible to transcend that ambiguity. It will appear that the issue of what is a domestic court that is either unwilling or unable is in fact an old international law question whose understanding can be improved by a dynamic reading of the evolution of international law. In final analysis, however, it may be that the International Criminal Court's capacity to emancipate itself entirely from the political will be limited, as the Prosecutor adopts a prosecutorial policy which, in itself, is unlikely to be reducible to law's categories.