Military of the European Union The military of the European Union today comprises the several national armed forces of the Union ' s 27 member states , as the area of defence is primarily the domain of nation states . European integration has however been deepened in this field in recent years , with the framing of the Common Security and Defence Policy ( CSDP ) as well as the creation of separate international forces revolving around the EU ' s defence . A number of CSDP military operations have been deployed in recent years . Several prominent leaders , including German Angela Merkel , French President Nicolas Sarkozy , Italian Foreign Minister Franco Frattini and former Belgian Prime Minister Guy Verhofstadt , have voiced support for a common defence for the Union . This possibility was formally laid down in Article 42 of the Treaty on European Union upon the entry into force of the Treaty of Lisbon on 1 December 2009 . Additionally , the Treaty of Lisbon extended the " enhanced co - operation " provision to become available for application in the area of defence . This mechanism enables a minimum number of member states to deepen integration within the EUs institutional framework , without the necessity of participation for reluctant member states . The Polish government has announced its intention of examining the possibility of applying this provision in the area of defence during its Presidency of the Council of the European Union in the second half of 2011 . History . Following the end of World War II and the defeat of Nazi Germany , the Dunkirk Treaty was signed by France and the United Kingdom on 4 March 1947 as a " Treaty of Alliance and Mutual Assistance " against a possible German attack in the aftermath of World War II . The Dunkirk Treaty entered into force on 8 September 1947 . Western European states save Germany , Ireland , Sweden ( and Switzerland ) joined the NATO later along with the United States . The Treaty of Brussels was signed in 1948 . In the early 1950s , France , Germany , Italy and the Benelux countries made an attempt to integrate the militaries of mainland Western Europe , through the treaty establishing the European Defence Community . This scheme did however not enter into force , as it failed to obtain approval for ratification in the French National Assembly , where Gaullists feared for national sovereignty and Communists opposed a European military consolidation that could rival the Soviet Union . Nowadays , as 21 of the 27 EU member states are also members of NATO , some EU states cooperate on defence policy ( collective security ) albeit primarily through NATO rather than through the EU or aligned groups ( such as the Western European Union ) . However , the memberships of the EU , WEU , and NATO are distinct , and some EU member states are constitutionally committed to remain neutral on defence issues . Several of the new EU member states were formerly members of the Warsaw Pact . The EU currently has a limited mandate over defence issues , with a role to explore the issue of European defence agreed to in the Amsterdam Treaty , as well as oversight of the Helsinki Headline Goal Force Catalogue ( the ' European Rapid Reaction Force ' ) processes . However , some EU states may and do make multilateral agreements about defence issues outside of the EU structures . On 20 February 2009 the European Parliament voted in favour of the creation of Synchronized Armed Forces Europe ( SAFE ) as a first step towards a true European military force . SAFE will be directed by an EU directorate , with its own training standards and operational doctrine . There are also plans to create an EU " Council of Defence Ministers " and " a European statute for soldiers within the framework of Safe governing training standards , operational doctrine and freedom of operational action " . Implications of the Treaty of Lisbon . The entry into force of the Treaty of Lisbon triggered member states of the Western European Union ( WEU ) to scrap the organisation , which had largely become dormant , but they have kept the mutual defence clause of the Treaty of Brussels as a basis for a possible EU mutual defence arrangement . The Treaty of Lisbon also states that : Forces and arrangements . Common Security and Defence Policy . The defence arrangements which have been established under the EU institutions are part of the Common Security and Defence Policy ( CSDP ) , a branch of the Common Foreign and Security Policy ( CFSP ) . It should be noted that Denmark has an opt - out from the CSDP . Deployments . In 2004 , EU countries took over leadership of the mission in Bosnia and Herzegovina from NATO through the European Union Force ( EUFOR ) . The mission was given the branding of an EU initiative as the EU sponsored the force to further the force ' s image of legitimacy . There have been other deployments such as in Gaza and the Democratic Republic of Congo . In 2007 , the then European High Representative for Foreign Policy , Javier Solana indicated the EU could send troops to Georgia , perhaps alongside Russian forces . Separate initiatives . Separate initiatives by Member States that revolve around the defence of the European Union in some way or another , or acting as a European standing army . Militaries of Member States . Defence Spending . The combined defence budgets of the 27 EU member states in 2008 amounted to €200 . 2 billion ( $ 260 . 4 billion ) . This represents 1 . 63 % of European Union GDP , second only to the US military ' s €477 . 4 billion ( $ 620 . 5 billion ) 2008 defence budget , which represents 4 . 5 % of United States GDP . The EU figures include the spending for joint projects such as the Eurofighter and joint procurement of equipment . France and the United Kingdom account for more than 45 % of EU military expenditure . Active Military Forces . The EU ' s combined active troop total in 2008 was 1 , 800 , 707 and as of 2008 , the European Union has an average of 80 , 177 Land Force troops deployed around the world . During a military surge the European Union can deploy 464 , 574 Land Force troops , of those 464 , 574 troops , 125 , 237 can be sustained in a large scale long term conflict .