This article argues in favor of holding leaders responsible for international crimes but also worries quite a bit about what would be a fair standard of mens rea for these leaders. Section 1 sets out the key facts of the case and the basis of the International Criminal Tribunal for Yugoslavia Trial Chamber's conviction of General Tihomir Blaskic. Section 2 presents the basis of the ICTY5 Appeals Court's overruling of the Trial Chamber's decision. Section 3 focuses on the issue of mens rea concerning those who command others to commit such crimes as the taking of hostages and the use of human shields. Section 4 sets out a limited argument in favor of negligence as a type of mens rea in international criminal law. Finally, section 5 discusses the relevance of the idea of the theory of joint criminal liability in such cases.