Command responsibility, as a modern doctrine of criminal law, originates in the atrocities committed by members of the Imperial Japanese Army in the Philippines between 9 October 1944 and 2 September 1945. That the atrocities – starvation, execution, rape and burning of homes – violated the laws of war is uncontroversial. More controversial, and of enduring doctrinal interest, was the potential individual responsibility of General Yamashita, Commanding General of the Imperial Army’s Fourteenth Group prior to his surrender to US forces.

Criminal responsibility for contributing to a group acting with a common purpose is a key – yet controversial – issue in ICL. On the one hand, it is well-known that international crimes are normally committed by groups of people acting pursuant to joint plans or agreements. This calls for liability theories that establish responsibility based on the accused’s participation in a collective criminal effort. On the other hand, the principles of individual criminal responsibility and personal guilt proscribe the attribution of crimes committed by others to the accused merely because of his/her membership in a group or organization.

Commission is a well-established form of liability in ICL.In the Tadić Appeal Judgment,the ICTY confirmed that commissionis first and foremost ‘the physical perpetration … by the offender himself’.Additionally, multiple other forms of commission exist, some of which do not necessarily require that a perpetrator commit a physical offence directly.

Historically, aiding and abetting, as such, was not included in the Charter of the Nuremberg Tribunal or the Charter of the Tokyo Tribunal. Rather, Control Council Law No. 10 first provided for the criminal prosecution of persons who were ‘accessor[ies] to the commission of any … crime or ordered or abetted the same’. Oddly, aiding and abetting was also not explicitly included in the 1950 Nuremberg Principles or the 1954 ILC Draft Code of Crimes – in both documents ‘complicity’ is employed – but it reappeared in Article 3(2) of the 1991 ILC Draft Code of Crimes and in Article 2(3)(d) of the 1996 ILC Draft Code of Crimes. Nonetheless, it is now consistently found in the Statutes of all modern international criminal tribunals.

Despite recent developments, prosecuting attempts to commit international crimes have typically been rare at the international level. The infrequency of prosecution can be explained by several factors. Some scholars have argued that attempt liability for war crimes, crimes against humanity or genocide might not have met the ‘seriousness requirement’ in order to be brought within the ICTY and the ICTR’s respective jurisdictions or might not ‘have implicated the collective considerations of peace and security that animated the creation of the tribunals in first instance’. Moreover, according to Schabas, prosecuting attempted international crimes was not entirely necessary since international courts and tribunals were generally established ex post facto, that is once such crimes have already been committed.

While it is impossible to summarize the findings of this book, a few observations, points of interest, can be made. First of all, a few words on the customary law status of the modes of liability and inchoate concepts of liability that we discuss.

This chapter examines the concept of co-perpetration, as defined and developed in the jurisprudence of the ICC. To this end, the research contained herein is divided into two separate, yet interrelated, parts that focus on the two distinct forms of co-perpetration, which the Court has recognized in its case law: ‘direct’ and ‘indirect’ co-perpetration.