On May 25, 1993, United Nations Security Council resolution 827 established the International Criminal Tribunal for the former Yugoslavia (ICTY) “for the sole purpose of prosecuting persons responsible for serious violations of international humanitarian law committed in the territory of the former Yugoslavia.” The limited geographic and temporal focus of the ICTY belies its importance in the development of international criminal law. As the first international tribunal since the Nuremberg Tribunals to interpret the crimes of genocide, crimes against humanity, and war crimes, the ICTY and the subsequently established Rwandan Tribunal (ICTR) have developed an enormous new body of international law, spanning substantive criminal principles, procedural rules, and sentencing practices (Danner 2006). These courts have concluded, for example, that genocide can be committed through the crime of rape, that civilians – and not just military leaders – can be convicted under the theory of “command responsibility,” and that war crimes can be committed during civil wars. All of these conclusions represent a significant expansion of the legal texts that formed the basis of their decisions. Moreover, most of these principles have become entrenched in the permanent International Criminal Court (ICC), thus ensuring their influence well beyond their original limited purpose.

The judges at the ICTY and the ICTR have thus played a central role in a task that is traditionally reserved for states: the creation of international law. As such, the questions that motivate this book are acutely relevant: Who are these judges? Where does their authority come from?