Genocide may be prosecuted by international or national courts. The preference of international law for the latter can be seen in the decision of the drafters of the Convention to establish an obligation to repress genocide without at the same time creating an international jurisdiction, although such a possibility was certainly contemplated and, indeed, expected at some time in the future. It is also evident in the principle of ‘complementarity’ which defines the operations of the International Criminal Court, established in 2002 following the entry into force of the Rome Statute. Pursuant to this principle, genocide offenders are, preferably, to be tried before domestic or national courts. Only when these fail should the international jurisdiction become operational.

From a policy standpoint, however, one or the other system may not always be preferable for genocide prosecution. Where a domestic judicial system operates in an effective manner, it may be quite capable of dealing appropriately with the crimes of the past. But, sometimes, a domestic judicial system will be operational yet require, for its own credibility, that some international trials be held to deal with major cases. Rwanda chose this approach when, in 1994, it requested that the Security Council establish an international criminal court. Accordingly, the Security Council resolution creating the International Criminal Tribunal for Rwanda stressed ‘the need for international co-operation to strengthen the courts and judicial system of Rwanda, having regard in particular to the necessity for those courts to deal with large numbers of suspects’.