The Vital Interest to Protect Europe: A Change in the International Regime on the Use of Force to Foster European Defence?

The UK-France joint nuclear statement of 10 July 2025 and the Treaty between the United Kingdom and Germany on friendship and bilateral cooperation of 17 July 2025 refer to an old doctrine of international law: the doctrine of vital interests. The recourse to a legal doctrine that predates not only the European Union but also the prohibition of the use of force and the United Nations could indicate that the most powerful European States are seeking to protect the entire European territory from war by employing all the instruments available under international law. This objective cannot be attained using EU law. This paper argues that these powerful States, among which there are the two nuclear powers in the Western Europe, namely the United Kingdom and France, are using old categories of international law to pursue the supreme objective of the territorial integrity of the European continent: Europe’s vital interest, indeed.