The address that follows was delivered at the V St. Petersburg International Legal Forum on May 29, 2015 and examines the particular set of challenges that faced the international community in the aftermath of the 1994 Rwandan Genocide. Specifically, Judge Joensen identifies how the International Criminal Tribunal for Rwanda (ICTR) interacted with national jurisdictions and how these interactions impacted the ICTR. In this regard, three important areas of international cooperation relevant to the ICTR are discussed: (1) the assistance that the ICTR received in relation to its core work, including the tracking and arrest of fugitives, investigations and enforcement of sentences; (2) capacity building and outreach programmes; and (3) the referral of cases to national jurisdictions. Judge Joensen demonstrates how ad hoc Tribunals, like the ICTR, are dependent on assistance from other countries to carry out their core functions while also examining the specific relationship between the ICTR and Rwanda. Shedding light on the activities outside of the courtroom, Judge Joensen provides an overview of the programmes created by the ICTR to develop and empower both international and national justice systems. In this context and when providing an analysis of mutual cooperation, Judge Joensen uses the ICTR’s referral programme as an example of the compatibility and incompatibility between international and national jurisdictions from a judicial perspective. In concluding, an emphasis is placed on further discussions regarding the development of legal systems throughout the world and on the continued fight against impunity.