During the Cold War era, policymakers and think tank had it relatively easy since the holistic and apparently everlasting bipolar confrontation shaped the framework within which the main strategic choices were defined. With the end of that epoch and the eclipse of the Soviet empire, what was a given gave way. European as well as international security has become too multi-faceted to characterize by way of a single analytical model. Though military power remains crucial, the importance of economic power has clearly increased. Additionally, non-state actors have also emerged to an extent unknown in the old times of classical diplomacy.

The idea of a common defence policy for Europe dates back to 1948 with the Treaty of Brussels (signed by the UK, France and the Benelux countries), which had a mutual defence clause that paved the way for the Western European Union (WEU). Since then, European security policy has followed several different paths, developing simultaneously within the WEU, NATO and the EU.

Today, the European Union's Common Security and Defence Policy (CDSP) is an integral part of the EU's Common Foreign and Security Policy (CFSP).

The Common Security and Defence Policy (CSDP) sets the framework for EU political and military structures and for military and civilian missions and operations abroad. The 2016 EU Global Strategy lays out the strategy underlying the CSDP, while the Lisbon Treaty provides legal clarity on institutional aspects and strengthens the role of the European Parliament. The CSDP has undergone major strategic and operational changes recently. Faced with security challenges and popular demand for increased EU responses, the CSDP is continuing to evolve.

The Permanent Structured Cooperation in Defence (PSCD) (also added in the Lisbon Treaty - Articles 42 and 46 of the Treaty on European Union) refers to a deeper form of cooperation between EU countries. Under this framework, EU countries commit to developing their defence capacities more intensively and supply combat units for planned missions. The EDA assesses contributions, while the Council authorises the cooperation.

The EU may use civilian and military assets outside the EU for peace-keeping, conflict prevention and strengthening international security. The types of tasks that can be carried out under the CSDP are: humanitarian and rescue tasks; conflict prevention; tasks for combat forces in crisis management; joint disarmament operations; military advice and assistance tasks; tasks in post-conflict stabilisation.

Mediterranean macro-region is currently very turbulent, and crises there are causing a number of internal security challenges, such as the refugee crisis and terrorist attacks.

The situation has dramatically changed over the last ten years since the launch of the EU neighbourhood policy.

What was supposed to become a ring of friends surrounding Europe has turned into a ring of fire, with dire consequences for the EU in terms of migration and terrorism, consequences that are carrying sparks of instability to the heart of the Union.

So, in a challenging geopolitical environment, the EU cooperation on external security and defence need to be strengthened.