On 11 December 2017, the Council of the EU adopted the decision to establish the Permanent Structured Cooperation (PESCO Secretariat, 2021). PESCO aims to enhance defence cooperation and army interoperability between EU member states who are willing and able to participate (ibid). Concretely, it provides a framework to increase cooperation in the planning, development, investment, and operability of defence capabilities between the 25 participating EU member states (ibid; EDA, 2021). This way, PESCO is a collaborative effort to create “a coherent full spectrum of defence capabilities available to Member States for national and multinational (EU, NATO, UN, etc.) missions and operations” (PESCO Secretariat, 2021). It is a strong form of cooperation as participation in PESCO entails automatic subscription to the list of legally binding commitments enshrined in article 2 of Protocol 10 annexed to the Treaty on the European Union (TEU) (ibid).