The geopolitical context of the European Union (EU) has changed significantly in recent years, leading Member States to face new threats. Confronted with this situation, European leaders have agreed to work more closely together in defence and security. EU Member States are not cooperating appropriately, which has led to inefficient use of funds, wasteful duplication, and inadequate deployability of defence troops. The military industry is characterised by rising defence equipment costs as well as expensive Research and Development (R&D) costs, which limit the launch of new military programmes and have a direct impact on the EU Defence Technological and Industrial Base’s (EDTIB) competitiveness and innovation (EU Parliament and Council, 2021). The level of defence spending varies significantly amongst Member States. Increased solidarity is required to deliver joint defence capabilities, particularly through the engagement of the EU budget. The cost of non-cooperation between Member States in the field of defence and security is estimated at between €25 billion and €100 billion every year (Maelcamp, I.; Ungaro, A.R.).