The Crime of Aggression in Contemporary International Law in Light of the Recent Practice of States

The crime of aggression is defined in Article 8bis of the Rome Statute and is one of the four crimes under the jurisdiction of the International Criminal Court. This thesis explores the evolution, legal framework, and contemporary application of the crime of aggression in international law. Beginning with a historical overview, it traces the development of the legal concept of aggression from the attempted trial of Wilhelm II, through the crimes against peace precedent in the post-World War II military tribunals, through the adoption of the UN General Assembly’s Resolution 3314, to the inclusion of the crime in the Rome Statute and the 2017 activation of the jurisdiction of the International Criminal Court over it. The thesis then provides a detailed legal analysis of Article 8bis of the Rome Statute. The analysis follows the division of the crime into individual and state conduct. Finally, the study applies this legal framework to two contemporary armed conflicts: the Russia–Ukraine war and the war between Israel and Hamas. It is argued that the crime of aggression was committed in the first case but not in the second. This difference is due to the threshold clause of the crime. Through this case analysis, the thesis assesses the practical relevance and legal limitations of applying the crime of aggression in modern international law.