Mutual Defence in the European Union? The Imperative of Article 42.7 in Case the United States Abandons European Defence

Policy Brief, Centre for Security, Diplomacy and Strategy, Brussels School of Governance

Discussions on mutual defence in Europe often focus exclusively on NATO’s Article 5 — not at least because the overwhelming conventional and nuclear arsenal of the United States’ security guarantee for Europeans is unparalleled. The EU’s solidarity clause, Article 42.7 TEU, is often overlooked in this context but also constitutes a powerful tool.

The Policy Brief “Mutual Defence in the European Union? The Imperative of Article 42.7 in Case the United States Abandons European Defence”, published by the Centre for Security, Diplomacy and Strategy at the Brussels School of Governance, discusses the implications of this article and argues, among others:

• Article 42.7 TEU might become particularly relevant in two scenarios: the planned accession of Ukraine to the EU – more so if it happens before NATO accession – and potential abandonment by the United States (US) and its security guarantee for European allies through NATO.

• Reflections on Article 42.7 TEU must be adapted to today’s reality of European security and defence, and therefore also include a hybrid dimension and the possibility to cooperate with non-EU NATO members.

• The power of Article 42.7 TEU hinges on the key principles of deterrence: assurances and their credibility.

The full policy brief is available here.