solution, soon exhausted their usefulness and were abandoned by 1950. In the early 1950s, attempts to codify the crime of aggression in a "Code of Offences Against the Peace and Security of Mankind" stalled. After the 1940s, other crimes against international law, especially genocide and crimes against humanity, took priority over aggression. Maintenance of international peace and stability is a major function of the international order, and the Charter of the United Nations prohibits acts of aggression against other states. The prohibition of aggression is considered a peremptory norm in customary law, such that it is binding on states that are not members of the United Nations. The most important provision in the UN Charter is Article 2(4): "All Members shall refrain in their international relations from 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." "Force" refers to armed or military force, defined broadly: it can refer to conventional armies or irregular forces. Although not explicitly stated in the UN Charter, the conventional view is that only state actors can commit aggression. Although self-defense is an exception to the prohibition of force, claims of preventative and pre-emptive self-defense is largely rejected. On 14 December 1974, United Nations General Assembly Resolution 3314 elaborated on the prohibition of the use of force in the UN Charter. Although not legally binding, it influenced the Rome Statute's definition of aggression. Resolution 3314 generally defines aggression as "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, as set out in this Definition." It includes an incomplete list of acts of aggression and confirms that aggression are committed by one state against another, excluding non-state actors. The resolution also refers to "crime of aggression" and makes it clear that there is individual criminal liability for aggression. Customary law It is generally agreed by scholars of international criminal law that the crime of aggression is part of international customary law, but there is no agreement on the exact scope of aggression that is covered in customary law. This threshold is probably high, in order to distinguish criminal aggression from other acts of aggression. According to Antonio Cassese, the customary criminalization of aggression covers