The Mental Incapacity Defence in International Criminal Law: Ramifications from the Ongwen Trial Judgment

The defence of mental incapacity raises unique challenges in the particular context of mass atrocity and international criminal law. Yet, it has remained largely unexplored in the jurisprudence of international courts and tribunals. The Trial Chamber judgment issued by the International Criminal Court in the case of Dominic Ongwen offered a unique opportunity to remedy this and clarify the legal contours of the defence. Unfortunately, the court engaged minimally with these issues. This article examines the court’s reasoning in the Ongwen case and the lessons that may be learnt from it about the operation of the defence, particularly in relation to the treatment of expert evidence. It is contended that while there were significant shortcomings in the claim put forward by Ongwen in the aftermath of the judgment, the prospects of advancing a successful defence of mental incapacity based on control-related disorders in the future appear limited.