Samenvatting

This paper focuses on the criticism that tribunals such as the International Criminal Tribunal for the Former Yugoslavia (ICTY) and the International Criminal Tribunal for Rwanda (ICTR)2, by virtue of their reliance on customary law and other methods of determining existing norms, appear to violate the principle of legality. Two main questions will be addressed. First, whether the tribunals fail to conduct a fair trial by neglecting the principle of legality, and secondly, whether this use of a different substantive International Criminal Law compared to the International Criminal Court (ICC), affects the effectiveness of the international criminal justice system.