Western European Union
Union de l'Europe occidentale
Flag of WEU
1954–1990 1990–1995 1995–2011
Historical eraCold War
23 October 1954
• Cultural tasks transf. to CoE
1 January 1960
27 October 1984
• Platform on European Security Interests
27 October 1987
19 June 1992
• ESDI introduced
4 June 1996
1 December 2009
• Abolition
30 June 2011
Preceded by
Succeeded by
Western Union (alliance)
European Union
Today part ofEuropean Union (CSDP)
Council of Europe

The Western European Union (WEU; French: Union de l'Europe occidentale, UEO; German: Westeuropäische Union, WEU) was the international organisation and military alliance that succeeded the Western Union (WU) after the 1954 amendment of the 1948 Treaty of Brussels. The WEU implemented the Modified Brussels Treaty. During the Cold War, the Western Bloc included the WEU member-states, plus the United States and Canada, as part of the North Atlantic Treaty Organization (NATO).[1]

The Cold War ended c. 1991, and at the turn of the 21st century, WEU tasks and institutions were gradually transferred to the European Union (EU), providing central parts of the EU's new military component, the European Common Security and Defence Policy (CSDP). This process was completed in 2009 when a solidarity clause between the member states of the European Union, which was similar (but not identical) to the WEU's mutual-defence clause, entered into force with the Treaty of Lisbon. The states party to the Modified Treaty of Brussels consequently decided to terminate that treaty on 31 March 2010, with all the WEU's remaining activities to cease within 15 months.[2] On 30 June 2011, the WEU officially ceased to exist; with the European Union taking over its activities.[3]



Further information: Treaty of Brussels and Western Union (alliance)

The Treaty of Brussels was signed by the United Kingdom, France, Belgium, Luxembourg, and the Netherlands on 17 March 1948, establishing the Western Union (WU), an intergovernmental defence alliance that also promoted economic, cultural and social collaboration.

The need to back up the commitments of the North Atlantic Treaty with appropriate political and military structures led to the creation of the North Atlantic Treaty Organisation (NATO). In December 1950 the parties to the Treaty of Brussels decided to transfer the headquarters, personnel, and plans of the Western Union Defence Organisation (WUDO) to NATO, whose Supreme Headquarters Allied Powers Europe (SHAPE) took over responsibility for the defence of Western Europe.[4][5][6][7][8]

The establishment of NATO, along with the signing of a succession of treaties establishing the Organisation for European Economic Cooperation (April 1948), the North Atlantic Treaty Organisation (April 1949), the Council of Europe (May 1949) and the European Coal and Steel Community (April 1951), left the Treaty of Brussels and its Western Union devoid of authority.

1954–1984: General dormancy

Further information: London and Paris Conferences, Treaty of Brussels § Modification, and General Treaty

First, 9-star flag (1993–1995)

The Western Union's founding Treaty of Brussels was amended at the 1954 Paris Conference as a result of the failure of the Treaty establishing the European Defence Community to gain French ratification: The General Treaty (German: Deutschlandvertrag) of 1952 formally named the EDC as a prerequisite of the end of Allied occupation of Germany, and there was a desire to include Germany in the Western defence architecture.[9]

The Modified Brussels Treaty (MBT) transformed the Western Union into the Western European Union, at which point Italy and West Germany were admitted. Although the WEU established by the Modified Brussels Treaty was significantly less powerful and ambitious than the original Western Union, German membership of the WEU was considered sufficient for the military occupation of Germany to end in accordance with the General Treaty.[9]

The signatories of the Paris Agreements stated their three main objectives in the preamble to the Modified Brussels Treaty:

The social and cultural aspects of the Treaty of Brussels were handed to the Council of Europe (CoE) to avoid duplication of responsibilities.[10] This, in addition to the existence of NATO, marginalised the WEU, and caused it to be largely defunct.

On 1 January 1960 in accordance with the decision taken on 21 October 1959 by the Council of Western European Union and with Resolution(59)23 adopted on 16 November 1959 by the Committee of Ministers of the Council of Europe, the WEU activities in social and cultural areas (Social Committee, Public Health Committee, Joint Committee on the Rehabilitation and Resettlement of the Disabled and Cultural Committee) were transferred to the Council of Europe which was already running programmes in these fields. The European Universities Committee (see CM(60)4; C(59)127 and CM(59)130) was transferred to the Council of Europe separately from the rest of WEU cultural activities.[11]

1984–1998: Revival

Further information: Rome Declaration and Petersberg Declaration

From the late 1970s onwards, efforts were made to add a security dimension to the European Communities' European Political Cooperation (EPC). Opposition to these efforts from Denmark, Greece and Ireland led the remaining EC countries – all WEU members – to reactivate the WEU in 1984 by adopting the Rome Declaration.[12] Prior to this point there had been minimal use of the provisions of the Modified Brussels Treaty.[13]

Hotel Petersberg, where the Petersberg tasks were defined in 1992.

In 1992, the WEU adopted the Petersberg Declaration, defining the so-called Petersberg tasks designed to cope with the possible destabilising of Eastern Europe. The WEU itself had no standing army but depended on cooperation between its members. Its tasks ranged from the most modest to the most robust, and included humanitarian, rescue and peacekeeping tasks as well as tasks for combat forces in crisis management, including peacemaking.[14]

At the 1996 NATO ministerial meeting in Berlin, it was agreed that the Western European Union would oversee the creation of a European Security and Defence Identity (ESDI) within NATO structures.[15] The ESDI was intended as a European 'pillar' within NATO, partly to allow European countries to act militarily where NATO wished not to, and partly to alleviate the United States' financial burden of maintaining military bases in Europe, which it had done since the Cold War. The Berlin agreement allowed European countries (through the WEU) to use NATO assets if it so wished.

1998–2009: Transfer of tasks to the EU

Further information: Common Security and Defence Policy

In 1998 the United Kingdom, which had traditionally opposed the introduction of European autonomous defence capacities, signed the Saint-Malo declaration. This marked a turning point as the declaration endorsed the creation of a European security and defense policy, including a European military force capable of autonomous action.[16] The declaration was a response to the Kosovo War in the late 1990s, in which the EU was perceived to have failed to intervene to stop the conflict.[17]

Concerns were voiced that an independent European security pillar could undermine NATO; In response to St. Malo, the former US-Secretary of State Madeleine Albright put forth the three famous D's: no duplication of what was done effectively under NATO, no decoupling from the US and NATO, and no discrimination against non-EU members such as Turkey.

High Representative Javier Solana (September 1999)

The Treaty of Amsterdam, which entered into force in 1999, transferred the WEU's Petersberg tasks to the EU, and stated that the EU's Common Security and Defence Policy (CSDP), replacing the WEU's ESDI, would be 'progressively framed' on the basis of these tasks.

In June 1999, the Cologne European Council decided to incorporate the role of the WEU within the EU, effectively abandoning the WEU. The Cologne Council also appointed Javier Solana as the High Representative for Common Foreign and Security Policy to help progress both the CFSP and the CSDP. On 20 November 1999 Solana was also appointed Secretary-General of the WEU. His being head of both organisations permits him to oversee the ongoing transfer of functions from the WEU to the EU.

In 2002 the Berlin agreement from 1996 was amended with the so-called Berlin Plus agreement, which allowed the EU to also draw on some of NATO's assets in its own peacekeeping operations.

Originally, under the Amsterdam Treaty, the WEU was given an integral role in giving the EU an independent defence capability, playing a major role in the Petersberg tasks; however that situation is changing. On 13 November 2000, WEU Ministers met in Marseille and agreed to begin transferring the organisation's capabilities and functions to the European Union, under its developing Common Foreign and Security Policy (CFSP) and Common Security and Defence Policy (CSDP).[18]

For example, on 1 January 2002, the WEU's Security Studies Institute and the Satellite Centre were transferred to the EU and became the European Union Institute for Security Studies and the European Union Satellite Centre. Notably, the role given to the WEU in the Amsterdam Treaty, was removed by the Nice Treaty. The Treaty of Lisbon has provisions for cooperation between the EU and both NATO (including the Berlin Plus agreement) and the WEU.[19][20] However the defence commitment, of Article 4 of the Brussels Treaty, has not been subsumed.[21] Article 42(7) of the Treaty of the European Union, as amended by the Treaty of Lisbon, could be viewed as incorporating that defence commitment into the EU framework.[22]

The European Union Institute for Security Studies (EUISS) and European Union Satellite Centre (EUSC), both established to function under the EU's CFSP pillar, were both replacements to the Western European Union Institute for Security Studies and the Western Union Satellite Centre which had been established to function in connection to the WEU.

With the transfer of responsibilities, the WEU's Parliamentary assembly was urged to dissolve itself, as it had a mandate to supervise WEU politics, not the EU's CSDP politics. But the Assembly saw itself as playing an important role, particularly with greater right of scrutiny, membership, experience and expertise in defence policy. Therefore, it renamed itself the "Interim European Security and Defence Assembly" and urged the European Convention to include it as a second chamber within the EU's institutional framework. Hence it argued it could effectively scrutinise the CSDP, help improve EU-NATO relations and be more suited, being composed of national parliamentarians, to the intergovernmental style of the CSDP.

However, with the European Constitution aiming to streamline and simplify the EU's foreign policy, for example combining the two main foreign policy posts, it was not seen as wise to then create a separate double legislature for the CFSP, instead, the European Parliament was granted greater scrutiny over foreign policy.[23]

2009–2011: Dissolution

Further information: Treaty of Lisbon

In 2009, the Treaty of Lisbon took over the WEU's mutual defence clause.[2] There was much discussion about what to do with the WEU following the introduction of Lisbon, including plans to scrap it.[24] On 30 March 2010 in a Written Ministerial Statement UK's Foreign Office Minister Chris Bryant gave notice that the UK intended to withdraw from the Western European Union within a year.[25] On 31 March 2010 the German Foreign Affairs Ministry announced Germany's intention to withdraw from the Modified Brussels Treaty.[26] That same year, the Spanish Presidency of the WEU, on behalf of the 10 Member States of the Modified Brussels Treaty, announced the collective decision to withdraw from the Treaty and to close the WEU organisation by June 2011.[27] On 30 June 2011 the WEU officially ceased to exist.


Since the end of World War II, sovereign European countries have entered into treaties and thereby co-operated and harmonised policies (or pooled sovereignty) in an increasing number of areas, in the European integration project or the construction of Europe (French: la construction européenne). The following timeline outlines the legal inception of the European Union (EU)—the principal framework for this unification. The EU inherited many of its present responsibilities from the European Communities (EC), which were founded in the 1950s in the spirit of the Schuman Declaration.

  S: signing
  F: entry into force
  T: termination
  E: expiry
    de facto supersession
  Rel. w/ EC/EU framework:
   de facto inside
                  European Union (EU) [Cont.]  
European Communities (EC) (Pillar I)
European Atomic Energy Community (EAEC or Euratom) [Cont.]      
/ / / European Coal and Steel Community (ECSC)  
(Distr. of competences)
    European Economic Community (EEC)    
            Schengen Rules European Community (EC)
'TREVI' Justice and Home Affairs (JHA, pillar II)  
  / North Atlantic Treaty Organisation (NATO) [Cont.] Police and Judicial Co-operation in Criminal Matters (PJCC, pillar II)

Anglo-French alliance
[Defence arm handed to NATO] European Political Co-operation (EPC)   Common Foreign and Security Policy
(CFSP, pillar III)
Western Union (WU) / Western European Union (WEU) [Tasks defined following the WEU's 1984 reactivation handed to the EU]
[Social, cultural tasks handed to CoE] [Cont.]                
      Council of Europe (CoE)
Entente Cordiale
S: 8 April 1904
Dunkirk Treaty[i]
S: 4 March 1947
F: 8 September 1947
E: 8 September 1997
Brussels Treaty[i]
S: 17 March 1948
F: 25 August 1948
T: 30 June 2011
London and Washington treaties[i]
S: 5 May/4 April 1949
F: 3 August/24 August 1949
Paris treaties: ECSC and EDC[ii]
S: 18 April 1951/27 May 1952
F: 23 July 1952/—
E: 23 July 2002/—
Rome treaties: EEC and EAEC
S: 25 March 1957
F: 1 January 1958
WEU-CoE agreement[i]
S: 21 October 1959
F: 1 January 1960
Brussels (Merger) Treaty[iii]
S: 8 April 1965
F: 1 July 1967
Davignon report
S: 27 October 1970
Single European Act (SEA)
S: 17/28 February 1986
F: 1 July 1987
Schengen Treaty and Convention
S: 14 June 1985/19 June 1990
F: 26 March 1995
Maastricht Treaty[iv][v]
S: 7 February 1992
F: 1 November 1993
Amsterdam Treaty
S: 2 October 1997
F: 1 May 1999
Nice Treaty
S: 26 February 2001
F: 1 February 2003
Lisbon Treaty[vi]
S: 13 December 2007
F: 1 December 2009

  1. ^ a b c d e Although not EU treaties per se, these treaties affected the development of the EU defence arm, a main part of the CFSP. The Franco-British alliance established by the Dunkirk Treaty was de facto superseded by WU. The CFSP pillar was bolstered by some of the security structures that had been established within the remit of the 1955 Modified Brussels Treaty (MBT). The Brussels Treaty was terminated in 2011, consequently dissolving the WEU, as the mutual defence clause that the Lisbon Treaty provided for EU was considered to render the WEU superfluous. The EU thus de facto superseded the WEU.
  2. ^ Plans to establish a European Political Community (EPC) were shelved following the French failure to ratify the Treaty establishing the European Defence Community (EDC). The EPC would have combined the ECSC and the EDC.
  3. ^ The European Communities obtained common institutions and a shared legal personality (i.e. ability to e.g. sign treaties in their own right).
  4. ^ The treaties of Maastricht and Rome form the EU's legal basis, and are also referred to as the Treaty on European Union (TEU) and the Treaty on the Functioning of the European Union (TFEU), respectively. They are amended by secondary treaties.
  5. ^ Between the EU's founding in 1993 and consolidation in 2009, the union consisted of three pillars, the first of which were the European Communities. The other two pillars consisted of additional areas of cooperation that had been added to the EU's remit.
  6. ^ The consolidation meant that the EU inherited the European Communities' legal personality and that the pillar system was abolished, resulting in the EU framework as such covering all policy areas. Executive/legislative power in each area was instead determined by a distribution of competencies between EU institutions and member states. This distribution, as well as treaty provisions for policy areas in which unanimity is required and qualified majority voting is possible, reflects the depth of EU integration as well as the EU's partly supranational and partly intergovernmental nature.


The WEU was headquartered in Brussels, with a staff of 65 and an annual budget of €13.4 million.[24] It was composed of the Council of the WEU (the Council) and the Assembly of the WEU (the Assembly).

Council of Ministers

The WEU was led by a Council of Ministers, assisted by a Permanent Representatives Council on the ambassadorial level.

Parliamentary Assembly

Main article: Assembly of the Western European Union

Flag of the WEU Assembly

A Parliamentary Assembly (composed of the delegations of the member states to the Parliamentary Assembly of the Council of Europe) supervised the work of the Council, but it did not have any obligations on the Council. The Assembly of WEU was a consultative institution.

Western European Armaments Group

WEAG emblem

The Independent European Program Group (IEPG) was established as a forum for armaments cooperation in 1976 with the aim of creating a European Armaments Agency. Since 1993 the WEU armaments cooperation forum has been known as Western European Armaments Group (WEAG). Its membership reached 19 in 2000: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Italy, Luxembourg, Netherlands, Norway, Poland, Portugal, Spain, Sweden, Turkey and the United Kingdom. The body closed on 23 May 2005.[28]

Western European Armaments Organisation

The Western European Armaments Organisation (WEAO) was intended as an Armaments Agency but operations were limited to a research cell. It provided support services in defence research and technology. It was created in 1996, and closed in August 2006.[29] These agencies were taken over by the European Defence Agency. Other transferred bodies include the Institute for Security Studies and the Satellite Centre.

European Operational Rapid Force

Main article: European Rapid Operational Force

Arms of the European Rapid Operational Force

On 15 May 1995, the Council of Ministers of the WEU met in Lisbon. During this meeting a declaration of the creation of the European Operational Rapid Force (EUROFOR) was made by France, Italy, Spain and Portugal. Eurofor became operational in June 1998 as a task force of the Western European Union.[30]


WEU participation as of 2011:
  •   Members
  •   Associate members
  •   Observers
  •   Associate partners

The Western European Union had ten member countries, six associate member countries, five observer countries and seven associate partner countries. On 14 June 2001, WEU Secretary General Solana stated that there was no foreseeable reason to change the status of the non member countries in the organisation.


All member countries of the WEU were also members of both NATO and the European Union. These are the only nations that had full voting rights.


Rome, 1992: Observer countries were members of the European Union, but not of NATO.1

1 Denmark was an exception, being member of both. It has an opt-out from the Treaty of Maastricht (1992), so that it does not participate in the CSDP of the European Union.

Associate members

Rome, 1992: Associate membership was created to include the European countries that were members of NATO but not of the European Union. Associate members Poland, the Czech Republic and Hungary joined the EU in 2004.

Associate partners

Kirchberg, 1994: Countries that at the time were not part of either NATO or of the EU. All of the following nations joined both NATO and the EU by 2007.


Further information: List of military and civilian missions of the European Union

The following missions, mainly in the Balkans, were deployed by the WEU:[31]

Non-military activities

The WEU initially had cultural and social (non-military) structures and activities, but these were transferred to the Council of Europe in 1960.[32]

See also


  1. ^ Wragg, David W. (1973). A Dictionary of Aviation (first ed.). Osprey. p. 279. ISBN 9780850451634.
  2. ^ a b "Statement of the Presidency of the Permanent Council of the WEU on behalf of the High Contracting Parties to the Modified Brussels Treaty – Belgium, France, Germany, Greece, Italy, Luxembourg, The Netherlands, Portugal, Spain and the United Kingdom" (PDF). Western European Union. 31 March 2010. Archived from the original (PDF) on 1 March 2011. Retrieved 15 January 2024.
  3. ^ Simma, Bruno; Khan, Daniel-Erasmus; Nolte, Georg; Paulus, Andreas, eds. (22 November 2012) [1994]. The Charter of the United Nations: A Commentary. Oxford Commentaries on International Law (3 ed.). Oxford: Oxford University Press. p. 1935. ISBN 9780191653872. Retrieved 13 August 2023. [...] the EU has taken over all activities of the former Western European Union which ceased to exist on 30 June 2011.
  4. ^ Hansard extract 18 February 1957
  5. ^ Duke, Simon (2000). The elusive quest for European security: from EDC to CFSP. Basingstoke, UK: Palgrave Macmillan. pp. 13–14. ISBN 978-0-312-22402-8. Retrieved 27 November 2010.
  6. ^ "Did you know that Europe already had a defensive military alliance prior to NATO?". Allied Command Operations (ACO). NATO. 2010. Archived from the original on 21 July 2011. Retrieved 8 August 2010.
  7. ^ Kaplan, Lawrence S. (2007). NATO 1948: the birth of the transatlantic Alliance. Lanham, Maryland: Rowman & Littlefield Publishers, Inc. pp. 139–165. ISBN 978-0-7425-3917-4. Retrieved 8 August 2010.
  8. ^ "Brussels Treaty Organisation (Resolution)". Hansard. 565. London: House of Commons of the United Kingdom. 18 February 1957. cc19-20W. Retrieved 27 November 2010.
  9. ^ a b Text of Modified Brussels Treaty on the WEU website Archived 20 December 2019 at the Wayback Machine from the Original (Accessed 22 Feb 18)
  10. ^ The Western European Union On CVCE website
  11. ^ "1948 - Documents, Records and Archives - www.coe.int". Council of Europe. Retrieved 15 January 2024.
  12. ^ "BBC Politics 97". www.bbc.co.uk.
  14. ^ "Summaries of EU Legislation - EUR-Lex". eur-lex.europa.eu.
  15. ^ "NATO Ministerial Meetings Berlin - 3-4 June 1996". www.nato.int.
  16. ^ "Franco–British St. Malo Declaration (4 December 1998)". 22 June 2015. Retrieved 18 August 2015.
  17. ^ Adam. "The Saint-Malo Declaration and its impact on ESDP after 10 years - Defence Viewpoints from UK Defence Forum". www.defenceviewpoints.co.uk. Retrieved 18 August 2015.
  18. ^ Marseille Declaration 2000 Archived 8 July 2017 at the Wayback Machine weu.int
  20. ^ Western European Union (WEU) europa.eu
  21. ^ EU Security Policy & the Role of the European Commission Archived 1 July 2007 at the Wayback Machine ec.europa.eu
  22. ^ Lords, The Committee Office, House of. "House of Lords - European Union - Tenth Report". publications.parliament.uk.((cite web)): CS1 maint: multiple names: authors list (link)
  23. ^ Occasional Paper n.57: The democratic legitimacy of the European Security and Defence Policy European Union Institute for Security Studies, April 2005
  24. ^ a b Rettman, Andrew (3 September 2009) European defence league poised for debate on dormant pact, EU Observer accessed 3 September 2009
  25. ^ "Announcements - GOV.UK". Fco.gov.uk. Archived from the original on 24 September 2012. Retrieved 25 August 2013.
  26. ^ "diplo - Startseite - HTTP Status 404" (in German). Auswaertiges-amt.de. Retrieved 25 August 2013.
  27. ^ "Ministerio de Asuntos Exteriores y de Cooperación | Gobierno de España". Ministry of Foreign Affairs and Cooperation. 19 December 2011. Archived from the original on 19 December 2011. Retrieved 15 January 2024.
  28. ^ "Western European Armaments Group". www.weu.int. Archived from the original on 1 June 2017. Retrieved 3 June 2007.
  29. ^ WEAO Website Archived 24 May 2007 at the Wayback Machine
  30. ^ Eurofor eurofor.it
  31. ^ "Shaping of a Common Security and Defence Policy - EEAS - European External Action Service - European Commission". EEAS - European External Action Service. Archived from the original on 13 January 2017.
  32. ^ Leaflet on rm.coe.int.