Russia, Ukraine, and crimes of aggression in international law.
Updated: Mar 10
With Russian military build up on the borders of Ukraine, and the arrival of US "lethal aid" to Kyiv, there have been news reports suggesting Russian-planned "false flag" operations in Eastern Ukraine as a "justification" for invasion of Ukraine. If true, it suggests a cynical plot to obfuscate potential crimes of aggression, precipitating a Russian invasion of Ukraine on the false premise of "self-defence". Such acts would raise serious questions of state violations of international law, and, potentially, individual criminal liability under international law for crimes of aggression.
The crime of aggression is the illegal waging of war. It is one of the core international crimes for which individuals may be prosecuted under universal jurisdiction principles.
The crime of aggression in international law between states evolved from the customary laws and practices of just war (“jus ad bellum”). It has also been called “crimes against peace”.
The United Nations Charter of 1945 provided that legitimate use of force is restricted to self-defence or further to authorisation issued by the UN Security Council. Article 2(4) expressly prohibits the “threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the Purposes of the United Nations”.
The UN Charter did not, however, explicitly define or provide for the “crime of aggression”, nor did it address individual criminal responsibility for illegal use of force contrary to the UN Charter.
The Charter of the International Military Tribunal at Nuremberg (IMT) established that individuals could be held criminally accountable for “crimes against peace” which included “planning, preparation, initiation or waging of a war of aggression”. The IMT’s jurisdiction was limited to prosecution of “the major war criminals of the European Axis”following the Second World War. However, it established an important normative precedent for individual criminal culpability for crimes recognised in international law, including the crime of aggression.
Principle VI of the Nuremberg Principles of 1950 set out the crimes for which individuals could be held responsible under international law, including crimes against peace, ie “planning, preparation, initiation or waging of a war of aggression”, echoing the IMT Charter.
The International Law Commission’s (ILC) draft codes in 1954, followed up in 1996, proposed the universal application of crimes of aggression to include criminal liability of individuals exercising military or political command. However, the draft code of 1954 lacked a clear definition of “aggression” or “acts of aggression”.
UN General Assembly Resolution 3314 (XXIX) of 1974 provided clarity, adopting the following definition of aggression set out in the Resolution’s Annex, article 1:
“Aggression is the use of armed force by a State against the sovereignty, territorial integrity or political independence of another State, or in any other manner inconsistent with the Charter of the United Nations…”
Article 3 set out a number of acts which “qualify as an act of aggression” that could amount to state violation of international law.
However, it was only very recently that universal recognition of individual criminal liability, and state responsibilities to implement national laws and procedures to prosecute individual crimes of aggression, has acquired significant and substantive legal weight.
When the Rome Statute of the International Criminal Court was adopted in 1998, the crime of aggression was included in the list of crimes over which the ICC has jurisdiction (article 5). However, the state parties failed to agree on a definition. As a compromise, the ICC’s jurisdiction over crimes of aggression was suspended pending further review.
UNGA Resolution 3314 provided the basis for the definition of “crime of aggression” incorporated into the Rome Statute by amendment adopted in 2010. The ICC’s jurisdiction over crimes of aggression was activated in 2018. Individuals in positions of military or political control can now be held criminally liable by an international court for the crime of aggression.
Article 8 bis of the Rome Statute is the contemporary universal point of reference for the meaning and scope of “crimes of aggression” and specific acts of aggression:
Article 8 bis, Rome Statute of the International Criminal Court
(1) …“crime of aggression” means the 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.
(2) …“act of aggression” means the use of armed force by a State against the sovereignty, territorial integrity or political independence of another State, or in any other manner inconsistent with the Charter of the United Nations. Any of the following acts, regardless of a declaration of war, shall, in accordance with United Nations General Assembly resolution 3314 (XXIX) of 14 December 1974, qualify as an act of aggression:
(a) The invasion or attack by the armed forces of a State of the territory of another State, or any military occupation, however temporary, resulting from such invasion or attack, or any annexation 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.
Activation of article 8 bis does not have retroactive effect, so crimes of aggression pre-dating 2018 fall outside the ICC’s remit.
As to the ICC's jurisdiction, neither Russia or Ukraine are state parties to the Rome Statute: both states signed the Rome Statute but have not ratified it, with Russia taking steps to withdraw altogether in 2016. As such, neither state is subject to the general jurisdiction of the ICC. Ukraine has accepted the jurisdiction of the ICC by declarations under article 12.3 of the Rome Statute, giving rise to ICC investigations into allegations of war crimes and crimes against humanity during and after the Maidan protests, and subsequent armed conflict in Crimea and eastern Ukraine. The ICC Prosecutor opened a preliminary examination, concluding, amongst other things, that there is a "reasonable basis" to to believe that war crimes and crimes against humanity had been committed in Ukraine by different parties to the conflict.
Aside from the material and territorial limits of its on-going investigation, the ICC does not have authority to investigate crimes of aggression alleged to have been committed by non-state parties. As such, accountability for alleged Russian crimes of aggression will only be possible in other fora.