Aggression in International Law

by

Constantine Antonopoulos

• LAST REVIEWED: 12 April 2019
• LAST MODIFIED: 30 October 2019
• DOI: 10.1093/obo/9780199796953-0061

Introduction

The crime of aggression, or crime against peace, was first introduced in the constituent instrument establishing the Nuremberg International Military Tribunal (IMT) (the London Charter, 1945) at the end of World War II. It was also included in the Charter of the Tokyo International Military Tribunal for the Far East (IMTFE) and Control Council Law No. 10, 1945. The criminalization of aggression in these instruments constitutes the culmination of a process that started at the end of World War I, with the arraignment of the German emperor Wilhelm II, by virtue of Article 227 of the Peace Treaty of Versailles, “for a supreme offence against international morality and the sanctity of treaties.” The prosecution of the crime of aggression before the Nuremberg and Tokyo IMTs met with strong criticism concerning the breach of the principle of legality (nullum crimen sine lege). However, the United Nations (UN) General Assembly, in G.A. Res. 95(I) (UN General Assembly 1946, cited under General Assembly Resolutions), and the International Law Commission (ILC), in the “Formulation of the Nürnberg Principles” (Yearbook of the International Law Commission 2 1950), endorsed the existence of the crime of aggression in customary law, with no opposition on the part of states. Hence, in the early 21st century it is universally accepted that the crime of aggression exists in customary law, although its precise definition, for the purposes of individual criminal responsibility, has been a matter of contention. No prosecutions for aggression followed the Nuremberg and Tokyo trials, and this crime remained in a state of lethargy until the establishment of the International Criminal Court (ICC) in 1998. Article 5, ICC Statute, includes aggression among the crimes within the Court’s jurisdiction. At the same time, Article 5(2) stipulates that the jurisdiction of the Court would not be exercised for aggression until a generally accepted definition of the crime was adopted. This definition was ultimately agreed upon at the first Review Conference of the ICC Statute, in Uganda (Kampala Conference), in June 2010 (new Article 8bis). The crime of aggression is closely connected with the resort to force by a state, unlike war crimes, genocide, and crimes against humanity, in which individual criminal responsibility is independent of the existence of state responsibility. Moreover, perpetrators of aggression, unlike the other three crimes, are exclusively state officials, particularly in the highest echelons of the state. The adoption of a definition of the crime of aggression in the ICC Statute is a major breakthrough that may clear the way for prosecutions of crimes against peace in the future, especially after the activation of the ICC jurisdiction over the crime of aggression in July 2018.

Historical Overview

The evolution of the crime of aggression traces the period from the establishment of the Nuremberg International Military Tribunal (IMT) to the adoption of the definition of the crime at the Kampala Conference in 2010. Recitals of this evolution are rather brief (though generally concise) in textbooks on international criminal law and become more detailed in ad hoc monographs on the crime of aggression and books on the use of force by states. In the course of the work of the Special Working Group on the Crime of Aggression, the Secretariat of the UN Preparatory Commission for the International Criminal Court prepared the lengthy and detailed Historical Review of Developments Related to Aggression (United Nations Preparatory Commission for the International Criminal Court 2003); this document is the most comprehensive text on the history of the evolution of the crime of aggression. Bantekas 2010 and Cryer, et al. 2014 contain concise historical overviews of the subject. See also the classic monographs Brownlie 1963, Dinstein 2017, and McDougall 2013 as well as Bassiouni and Ferencz 2008, Schabas 2004, Kress and Holtzendorff 2010, and Kress and Barriga 2016.

• Bantekas, Ilias. International Criminal Law. 4th ed. Oxford and New York: Hart, 2010.

  Chapter 13 contains a concise exposition of the development of the law, focusing on the evolution toward the definition of the crime of aggression adopted at the Kampala Conference in 2010.

• Bassiouni, M. Cherif, and Benjamin B. Ferencz. “The Crime against Peace and Aggression: From Its Origins to the ICC.” In International Criminal Law. Vol. 1, Sources, Subjects, and Contents. 3d ed. Edited by M. Cherif Bassiouni, 207–242. Leiden, The Netherlands: Martinus Nijhoff, 2008.

  An extensive and thorough exposition of the developments regarding the criminalization of aggression under international law.

• Brownlie, Ian. International Law and the Use of Force by States. Oxford: Clarendon, 1963.

  DOI: 10.1093/acprof:oso/9780198251583.001.0001

  In this classical monograph on the use of force by states, the author recites developments in state practice leading to the attribution of criminal responsibility to individuals for unlawful use of force prior to the Nuremberg trial. A very useful source of reference (see chapter 8, pp. 150–166).

• Cryer, Robert, Håkan Friman, Darryl Robinson, and Elizabeth Wilmshurst. An Introduction to International Criminal Law and Procedure. 3^d ed. Cambridge, UK: Cambridge University Press, 2014.

  DOI: 10.1017/CBO9781107588707

  Chapter 13 includes a brief account of the historical evolution of the law. The chapter then discusses the definition of the crime of aggression adopted at Kampala in 2010.

• Dinstein, Yoram. War, Aggression, and Self-Defence. 6th ed. Cambridge, UK: Cambridge University Press, 2017.

  DOI: 10.1017/CBO9780511920622

  Recites the developments in the law with regard to the crime of aggression from the end of World War I to the establishment of the International Criminal Court (ICC) and the Kampala Review Conference. A brief but concise presentation of the historical evolution of the crime (see chapter 5, pp. 132–141).

• Kress, Claus, and Stefan Barriga. The Crime of Aggression: A Commentary. Cambridge, UK: Cambridge University Press, 2016.

  This is a two-volume comprehensive legal analysis of the crime of aggression as defined at the Kampala Conference. It contains an extensive analysis of the historical evolution of the crime of aggression in contributions by experts on the subject (Volume 1, Part 1).

• Kress, Claus, and Leonie von Holtzendorff. “The Kampala Compromise on the Crime of Aggression.” Journal of International Criminal Justice 8.5 (2010): 1179–1217.

  DOI: 10.1093/jicj/mqq069

  The authors present an insider’s analytical account of the preparatory work leading to the adoption of the definition of the crime of aggression at Kampala. They stress the historical nature of the achievement and forecast the fulfillment of the Nuremberg legacy.

• McDougall, Carrie. The Crime of Aggression under the Rome Statute of the International Criminal Court. Cambridge, UK: Cambridge University Press, 2013.

  DOI: 10.1017/CBO9780511894589

  This is one of the most recent monographs on aggression in the early 21st century. Contains a brief and concise account of the developments prior to Nuremberg and the Cold War period and a detailed and extensive account of the developments leading to the Rome Conference 1998 and the negotiations culminating in the adoption of the definition of the crime of aggression at the Kampala Conference of 2010 (chapter 1).

• Schabas, William A. “Origins of the Criminalization of Aggression: How Crimes against Peace Became the ‘Supreme International Crime.’” Paper read at an international conference held in Trento, in May 2001. In The International Criminal Court and the Crime of Aggression. Edited by Mauro Politi and Giuseppe Nesi, 17–32. Aldershot, UK: Ashgate, 2004.

  This is a concise piece reciting the developments toward the stipulation of crimes against peace in the London Charter, 1945, and the Nuremberg judgment—an elucidating commentary on the reasons of inclusion of crimes against peace in the jurisdiction of the IMT despite and against the principle of legality.

• United Nations Preparatory Commission for the International Criminal Court, Working Group on the Crime of Aggression. Historical Review of Developments Related to Aggression. UN Doc. PCNICC/2002/WGCA/L.1 (2002). New York: United Nations, 2003.

  Read with the Annexes, Doc. PCNICC/2002/WGCA/L.1/Add.1, the most detailed historical overview of the crime of aggression. Focuses in great detail on the Nuremberg, Tokyo, and Control Council No. 10 proceedings and deals with each defendant separately. Also refers to post-1945 instances of aggression by states.