The Provision of Arms to the Victim of Armed Aggression: the Case of Ukraine

Abstract

In response to Russia’s naked act of aggression against Ukraine on 24 February 2022, several States openly provided arms to Ukraine. These arms deliveries triggered questions of whether the States were violating the law of neutrality and, in particular, the duty of impartiality. It was asked whether the provision of arms could be justified as an act of collective self-defence or as a countermeasure. Examining State practice since the 1930s, the paper shows that with the outlawry of war as an instrument of national policy States considered themselves entitled to discriminate against the aggressor and to provide weapons to the victim of aggression. This was reinforced by the prohibition of the use of force under the Charter of the United Nations. In case of an act of armed aggression, there is no longer a duty of impartiality. Under the UN Charter it falls to the Security Council to determine the existence of an act of aggression. If the Security Council is unable to make this determination due to the exercise of the veto by a permanent Council member, the victim of aggression must not be left without assistance. In this case, it falls to each State to determine whether there is an act of aggression. If it turns out later that there was no aggression, States providing arms to a belligerent may themselves have committed an internationally wrongful act. In the case of the Russian attack on Ukraine, however, there is no doubt about who the aggressor is. On 1 March 2022, the General Assembly, by a vote of 141 in favour, five against and 35 abstentions, deplored in the strongest terms the aggression by Russia against Ukraine.

Keywords: Prohibition of the use of force, aggression, law of neutrality, self-defence, countermeasures

JEL Classification: K33