In Lisbon 2007, the European Union (EU) established a new policy called the Common Security and Defence Policy (CSDP). With Brexit, the EU lost an important member state in political, military and...Show moreIn Lisbon 2007, the European Union (EU) established a new policy called the Common Security and Defence Policy (CSDP). With Brexit, the EU lost an important member state in political, military and financial terms, potentially harming the CSDP. EU foreign policy and the impact of member states leaving IOs have attracted much scholarly attention. Previous research has been published before the actual exit date or during the negotiations and therefore has not yet focused on the impact of Brexit on the CSDP. This paper aims to answer the question “How does Brexit influence the European Union’s Common Security and Defence Policy?” via a theory-testing process-tracing method. The single case study uses the theory of historical institutionalism. While the analysis provides evidence for path dependency and a critical juncture in CSDP development, there is ambiguity regarding the actual long-term impact of Brexit on the CSDP. Just months ago, the world was shaken by an unprecedented war in Ukraine, forcing the EU to accelerate its policy adjustment within this field. Which means that it is difficult to give an absolute answer to the RQ itself. However, it makes the outcome of the researched policy adjustment process quite clear. Keywords: Brexit, CSDP, defence, EU, securityShow less
