ASP Background Briefings | Development of the Crime of Aggression at the ICC

Article 2(4) of the United Nations Charter sets out a prohibition on the use of force “against the territorial integrity or political independence” of other States. After World War II, the International Military Tribunal at Nuremberg expanded upon this concept, creating the “crime of aggression.” This was the first time individuals were held responsible for conduct which previously had only been enforced against States under the Charter.

Thirty State Parties to the Rome Statute have ratified the Kampala Amendments from 2010. This means that the crime of aggression should be activated in December 2017, provided that the State Parties to the Rome Statue decide by a 2/3 majority vote to activate the Court’s jurisdiction for the crime.

If the activation process succeeds, the ICC may investigate and prosecute crimes of aggression. The Court may exercise jurisdiction either through State referral (Article 15bis), or by Security Council referral (Article 15ter). Alternatively, the Prosecutor for the Court could start an investigation. Jurisdiction will apply only for acts of aggression after the amendments come into force, and the “aggressor” State Party must not have opted out of the Court’s jurisdiction for aggression.

Article 8bis of the Rome Statute defines the crime of aggression as “planning, preparation, initiation or execution, by a person in a position effectively to exercise control over or to direct the political or military action of a State, of an act of aggression which, by its character, gravity and scale, constitutes a manifest violation of the Charter of the United Nations.”

Paragraph 2 designates an act of aggression as “the use of armed force by a state” against another State, which is not consistent with the UN Charter, most specifically Chapter 7. The acts designated as acts of aggression (even without a declaration of war) were codified from the UNGA Resolution 3314, and include:

(a) The invasion or attack by the armed forces of a State of the territory of another State, or any military occupation […] by the use of force of the territory of another State or part thereof;

(b) Bombardment by the armed forces of a State against the territory of another State or the use of any weapons by a State against the territory of another State;

(c) The blockade of the ports or coasts of a State by the armed forces of another State;

(d) An attack by the armed forces of a State on the land, sea or air forces, or marine and air fleets of another State;

(e) The use of armed forces of one State which are within the territory of another State with the agreement of the receiving State, in contravention of the conditions provided for in the agreement or any extension of their presence in such territory beyond the termination of the agreement;

(f) The action of a State in allowing its territory, which it has placed at the disposal of another State, to be used by that other State for perpetrating an act of aggression against a third State;

(g) The sending by or on behalf of a State of armed bands, groups, irregulars or mercenaries, which carry out acts of armed force against another State of such gravity as to amount to the acts listed above, or its substantial involvement therein.

It is unclear at this time how many State Parties will potentially enact domestic legislation providing for the Crime of Aggression. The biggest concern for most states is complementarity, and enacting domestic legislation could allow State Parties to potentially avoid ICC prosecution due to their domestic measures and possible domestic investigations into the crime. Furthermore, in line with the principle of only being tried once for one’s conduct, “ne bis in idem” will apply to the Crime of Aggression.


UN Charter, Art. 2(4), available at

International Crimes Database, Crime of Aggression, available at

The Global Campaign for Ratification and Implementation of the Kampala Amendments on the Crime of Aggression, Conditions for Action by the ICC, available at

Liechtenstein Institute on Self-Determination, Handbook: Ratification and Implementation of the Kampala Amendment to the Rome Statute of the ICC, available at

UN General Assembly, Rome Statute of the International Criminal Court (last amended 2010), (Jul. 17 1998), available at