The idea of a common defence policy for Europe dates back to 1948 when the UK, France, and the Benelux signed the Treaty of Brussels. The agreement included a mutual defence clause laying down the foundations for the creation of the Western European Union (WEU), which remained until the late 1990s, together with NATO, the principal forum for consultation and dialogue on security and defence in Europe.
Following the end of the Cold War and the subsequent conflicts in the Balkans, it became clear that the EU needed to assume its responsibilities in the field of conflict prevention and crisis management. The conditions under which military units could be deployed were already agreed by the WEU Council in 1992 but the so-called “Petersburg Tasks” where now integrated in the 1999 Treaty of Amsterdam. In addition, the post of the “High Representative for Common Foreign and Security Policy” was created to allow the Union to speak with ‘one face and one voice’ on foreign policy matters.
At the Cologne European Council in 1999, Member States reaffirmed the Union’s willingness to develop capabilities for autonomous action, backed up by credible military forces. A key development was the “Berlin Plus agreement” giving the EU, under certain conditions, access to NATO assets and capabilities.
In 2003 the former High Representative Javier Solana was tasked by the Member States to develop a Security Strategy for Europe. The document entitled ‘A Secure Europe in a Better World’, analysed for the first time the EU’s security environment and identified key security challenges and subsequent political implications for the EU. The implementation of the document was revised in 2008.
The Lisbon Treaty came into force in December 2009 and was a cornerstone in the development of the Common Security and Defence Policy (CSDP). The treaty includes both a mutual assistance and a solidarity clause and allowed for the creation of the European External Action Service (EEAS) under the authority of the High Representative of the Union for Foreign Affairs & Security Policy/Vice-President of the European Commission (HR/VP), Catherine Ashton. The two distinct functions of the newly created post give the HR/VP the possibility to bring all the necessary EU assets together and to apply a "comprehensive approach" to EU crisis management.
Since the creation in March 2002 of the European Union Police Mission in Bosnia and Herzegovina by Council Joint Action, some 30 civilian and military missions and operations have been launched under the CSDP. The EU is constantly improving its crisis management capabilities. Headline Goals, both civilian as well as military, have been defined and adapted to match the changing security environment.
The CSDP was on the agenda of the December 2013 European Council meeting when the heads of states discussed how to enhance defence capabilities, strengthen the defence industry and improve the effectiveness, visibility and impact of the CSDP.