Introduction

The Russian invasion of Ukraine on 24 February 2022 marks nothing less than a defining moment in the modern history of Europe. While it is currently unknown how the war will end and what the future trajectory of Russia as well as Ukraine will be, it is clear that the aggression reflects a paradigmatic change in interstate relations in Europe – and indirectly also globally.

From an institutional point of view it can be argued that the so-called European security order has been shattered – the principles and foundations for interstate relations in Europe crafted at the end of the Cold War have been brutally ignored. To be clear, the security situation in Europe has been deteriorating ever since Russia's annexation of Crimea in 2014 (and arguably well before that, although in less manifest ways) – but waging a full-scale war represents something qualitatively different.

Reactions to the invasion have been massive, first and foremost in the equally sad and inspiring resistance by the Ukrainian armed forces and Ukrainian society at large. But also beyond Ukraine can principal developments be found, in how European states have chosen to redirect security policy in a conventional, territorial direction and substantially increasing spending on defence; even fundamentally changing security-political course, as in Finland's and Sweden's applications for membership of the North Atlantic Treaty Organization (NATO). Also the European Union (EU) has reacted intensely to the war, through a combination of sanctions against Russia and economic and political support for Ukraine. EU member states have committed economically as well as through military equipment, and in a novel approach also the EU has, for the first time, used its own budget to finance military equipment.

EU action in relation to the war is a principally interesting issue for a number of reasons. First, the EU was not as an actor one of the architects of the European security order; in that sense, it has had no formal role in the institutional setting of the European security order. Establishing that is not in any way ignoring its contribution to European security as one of the key mechanisms for peace in the post-Second World War period.