The Mens Rea Requirement
By Eugenia LevineGlobal Policy Forum
The modern doctrine of command responsibility can be defined as â€˜the responsibility of â€¦commanders for war crimes committed by subordinate members of their armed forces or other persons subject to their control.  This responsibility is based on a failure to prevent or punish subordinates for their unlawful actions. One of the controversial aspects surrounding recent developments of the doctrine has been the level of knowledge that commanders must possess before they become criminally responsible. Whilst it is accepted that actual knowledge of subordinates' crimes is sufficient, debate has centred on the appropriate level of "constructive" knowledge required to warrant individual criminal responsibility. 
Two different formulations of "constructive knowledge" have emerged. The stricter standard assesses whether the commander should, in the circumstances, have known of his subordinates unlawful actions, thereby placing him under a proactive duty to keep informed of troops' activities. Under a more lenient standard of "constructive knowledge", the commander is held responsible only where he fails to discover his subordinates' actions from information already available to him. Both tests have received support in post-World War II ("WWII") jurisprudence on command responsibility, hence the status of customary international law in regard to the applicable mens rea standard for command responsibility remains ambiguous and contentious.
Part I of this paper attempts to trace the development of the command responsibility doctrine from early origins to its applications in post-WWII jurisprudence, and its codification in Additional Protocol I to the Geneva Conventions of 1949.  Particular emphasis will be placed on the various theories of "constructive knowledge" that were proposed.
Part II will examine the interpretation of command responsibility by the International Criminal Tribunal for the former Yugoslavia ("the ICTY"), stressing the disagreement among the judgements as to the requisite mens rea standard.
Part III will consider the knowledge requirement in Article 28(a) of the Rome Statute of the International Criminal Court ("the ICC"),  and will highlight the potential uncertainty surrounding the interpretation that may be adopted by the ICC.
Part IV will consider the justifications for adopting a stricter "should have known" standard, and will conclude with the suggestion that this standard is more appropriate for promoting the accountability of commanders for the actions of their subordinates.
I: The Development of the Doctrine of Command Responsibility
I. A. The Origins of Command Responsibility
The origins of command responsibility date back centuries. In around 500 B.C., Sun Tzu wrote in Ping Fa - "the Art of War" - about the duty of commanders to ensure that subordinates conduct themselves with a certain level of civility in armed conflict.  In 1439, Charles VII of France issued the Ordinance of Orleans, which imposed blanket responsibility on commanders for all unlawful acts of their subordinates, without requiring any standard of knowledge. The first "international" recognition of commanders' obligations to act lawfully occurred during the trial of Peter von Hagenbach by an ad hoc tribunal in the Holy Roman Empire; Von Hagenbach was convicted of murder, rape, and other crimes which â€˜he as a knight was deemed to have a duty to prevent.'  The Tribunal did not, however, explicitly rely on a doctrine of command responsibility. 
The principle of command responsibility was further developed during the US Civil War. Article 71 of General Orders No. 100, "Instructions for the Government of Armies of the United States in the Field" (known as the "Lieber Code") imposed criminal responsibility on commanders for ordering or encouraging soldiers to wound or kill already disabled enemies. The first attempt at codifying the principle of command responsibility on a multinational level was The Hague Convention (IV) of 1907 Respecting the Laws and Customs of War on Land.  Article 1 of the Annex to the Convention stated that an armed force had to be â€˜commanded by a person responsible for his subordinates', but did not further detail commanders' particular obligations.
Undoubtedly, these early mentions of command responsibility constitute â€˜the foundational root of the modern doctrine.'  However, the theory of command responsibility based on a failure to prevent subordinates' crimes only became recognized following World War I. The Allied Powers' Commission on the Responsibility of the Authors of the War and on the Enforcement of Penalties recommended the establishment of an international tribunal, which would try individuals for â€˜order[ing], or, with knowledge thereof and with power to intervene, abstain[ing] from preventing or taking measures to prevent, putting an end to or repressing, violations of the laws or customs of war.'  This recommendation constituted a â€˜revolutionary advance in international jurisprudence',  because it advocated