The EU and Its Member States at War in Ukraine? Collective Self-defence, Neutrality and Party Status in the Russo-Ukraine War

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Table of Contents: I. Introduction. – II. Aid and assistance provided to Ukraine since February 2022. – II.1. The European Union and its Member States. – II.2. The United States of America, the United Kingdom and Canada. – II.3. Russia’s response. – II.4. Reactions from other states. – II.5. Conclusion. – III. Jus ad bellum, neutrality law, and jus in bello: the need for legal coherence. – III.1. Collective self-defence. – III.2. Different shades of neutrality? – III.3. Party status. – IV. Conclusion.

Abstract: To assist Ukraine in defending itself against Russian aggression, the EU invoked the European Peace Facility to “finance the provision of […] military equipment and platforms designed to deliver lethal force for defensive purposes”. It marks the first time that the EU is funding the provision of lethal equipment to a third state. In October 2022, the EU announced the creation of EUMAM Ukraine to train Ukrainian Armed Forces to use the weapons EU Member States have provided. Since February 2022, the EU’s military aid and assistance has only increased. EU Member States are also providing military aid and assistance bilaterally, including training Ukrainian soldiers. In so doing, they are aligning their assistance with “like-minded” partners and NATO Member States, particularly the United States of America, the United Kingdom and Canada. This Article will assess the supply of military aid and equipment to Ukraine as well as the training of UAF through the lens of international law. One wonders whether the EU’s military aid and assistance amounts to collective self-defence, even if none of the supporting actors have invoked art. 51 UN Charter. The argument could be made that the EU and its Member States are breaching neutrality law in supplying lethal aid to Ukraine, albeit it has been argued that neutrality law is no longer relevant in the post charter era. The question also arises whether these actors have become parties to the conflict, even if supporting states and the EU frequently assert that they are not co-belligerents.

Keywords: European Union Peace Facility – military aid and assistance – neutrality law – collective self-defence – party status – Russian aggression against Ukraine.

European Papers, Vol. 8, 2023, No 3, pp. 1697-1740
ISSN 2499-8249
- doi: 10.15166/2499-8249/737

* Assistant Professor in public international law, Utrecht University,


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