European Union

The European Union (EU) is a supranational political and economic union of 27 member states that are located primarily in Europe. The union has a total area of 4,233,255 km² (1,634,469 sq mi) and an estimated population of more than 450 million as of 2025. The EU is often described as a sui generis political entity combining characteristics of both a federation and a confederation.

Containing 5.5% of the world population in 2023, EU member states generated a nominal gross domestic product (GDP) of around €17.935 trillion in 2024, accounting for approximately one sixth of global economic output. Its cornerstone, the Customs Union, paved the way to establishing an internal single market based on standardised legal framework and legislation that applies in all member states in those matters, and only those matters, where the states have agreed to act as one. EU policies aim to ensure the free movement of people, goods, services and capital within the internal market; enact legislation in justice and home affairs; and maintain common policies on trade, agriculture, fisheries, and regional development.

Passport controls have been abolished for travel within the Schengen Area. The eurozone is a group composed of the 21 EU member states that have fully implemented the EU's economic and monetary union and use the euro currency. Through the Common Foreign and Security Policy, the union has developed a role in external relations and defence. It maintains permanent diplomatic missions throughout the world and represents itself at the United Nations, the World Trade Organization, the G7 and the G20. In 2012, the EU was awarded the Nobel Peace Prize.

The EU was established, along with its citizenship, when the Maastricht Treaty came into force in 1993, and was incorporated as an international legal juridical person upon entry into force of the Treaty of Lisbon in 2009. Its beginnings can be traced to the Inner Six states (Belgium, France, Italy, Luxembourg, the Netherlands, and West Germany) at the start of modern European integration in 1948, and to the Western Union, the International Authority for the Ruhr, the European Coal and Steel Community, the European Economic Community and the European Atomic Energy Community, which were established by treaties. These increasingly amalgamated bodies grew, with their legal successor the EU, both in size through the accessions of a further 22 states from 1973 to 2013, and in power through acquisitions of policy areas. In 2020, the United Kingdom became the only member state to leave the EU; ten countries are aspiring or negotiating to join it.

History

Background: World Wars and aftermath

Internationalism and visions of European unity had existed since well before the 19th century, but gained particularly as a reaction to World War I and its aftermath. In this light the first advances for the idea of European integration were made. In 1920 John Maynard Keynes proposed a European customs union for the struggling post-war European economies, and in 1923 the oldest organisation for European integration, the Paneuropean Union was founded, led by Richard von Coudenhove-Kalergi, who later would found in June 1947 the European Parliamentary Union (EPU). Aristide Briand—who was Prime Minister of France, a follower of the Paneuropean Union, and Nobel Peace Prize laureate for the Locarno Treaties—delivered a widely recognised speech at the League of Nations in Geneva on 5 September 1929 for a federal Europe to secure Europe and settle the historic Franco-German enmity.

With large-scale war being waged in Europe once again in the 1930s and becoming World War II, the question of what to fight against and what for had to be agreed on. A first agreement was the Declaration of St James's Palace of 1941, when Europe's resistance gathered in London. This was expanded on by the 1941 Atlantic Charter, establishing the Allies and their common goals, inciting a new wave of global international institutions like the United Nations (founded 1945) or the Bretton Woods System (1944).

In 1943 at the Moscow Conference and Tehran Conference, plans to establish joint institutions for a post-war world and Europe increasingly became a part of the agenda. This led to a decision at the Yalta Conference in 1944 to form a European Advisory Commission, later replaced by the Council of Foreign Ministers and the Allied Control Council, following the German surrender and the Potsdam Agreement in 1945.

By the end of the war, European integration became seen as an antidote to the extreme nationalism that had caused the war. On 19 September 1946, in a much recognised speech, Winston Churchill, speaking at the University of Zürich, reiterated his calls since 1930 for a "European Union" and "Council of Europe", coincidentally parallel to the Hertenstein Congress of the Union of European Federalists, one of the then founded and later constituent members of the European Movement. One month later, the French Union was installed by the new Fourth French Republic to direct the decolonisation of its colonies so that they would become parts of a European community.

By 1947, a growing rift between the western Allied Powers and the Soviet Union became evident as a result of the rigged 1947 Polish legislative election, which constituted an open breach of the Yalta Agreement. March of that year saw two important developments. First was the signing of the Treaty of Dunkirk between France and the United Kingdom. The treaty assured mutual assistance in the event of future military aggression against either nation. Though it officially named Germany as a threat, in reality the actual concern was for the Soviet Union. A few days later came the announcement of the Truman Doctrine which pledged American support for democracies to counter the Soviets.

Initial years and the Paris Treaty (1948‍–‍1957)

Immediately following the February 1948 coup d'état by the Communist Party of Czechoslovakia, the London Six-Power Conference was held, resulting in the Soviet boycott of the Allied Control Council and its incapacitation, an event marking the beginning of the Cold War. The year 1948 marked the beginning of the institutionalised modern European integration. In March 1948 the Treaty of Brussels was signed, establishing the Western Union (WU), followed by the International Authority for the Ruhr. Furthermore, the Organisation for European Economic Co-operation (OEEC), the predecessor of the OECD, was also founded in 1948 to manage the Marshall Plan, which led to the Soviets creating Comecon in response. The ensuing Hague Congress of May 1948 was a pivotal moment in European integration, as it led to the creation of the European Movement International, the College of Europe, and most importantly to the foundation of the Council of Europe on 5 May 1949 (which is now Europe Day). The Council of Europe was one of the first institutions to bring the sovereign states of (then only Western) Europe together, raising great hopes and fevered debates in the following two years for further European integration. It has since been a broad forum to further cooperation and shared issues, achieving for example the European Convention on Human Rights in 1950.

Essential for the actual birth of the institutions of the EU was the Schuman Declaration on 9 May 1950 (the day after the fifth Victory in Europe Day) and the decision by six nations (France, Belgium, Netherlands, Luxembourg, West Germany, and Italy) to follow Schuman and draft the Treaty of Paris. This treaty was created in 1952 the European Coal and Steel Community (ECSC), which was built on the International Authority for the Ruhr, installed by the Western Allies in 1949 to regulate the coal and steel industries of the Ruhr area in West Germany. Backed by the Marshall Plan with large funds coming from the United States since 1948, the ECSC became a milestone organisation, enabling European economic development and integration and being the origin of the main institutions of the EU such as the European Commission and Parliament.

Founding fathers of the European Union understood that coal and steel were the two industries essential for waging war, and believed that by tying their national industries together, a future war between their nations became much less likely. In parallel with Schuman, the Pleven Plan of 1951 tried but failed to tie the institutions of the developing European community under the European Political Community, which was to include the also proposed European Defence Community, an alternative to West Germany joining NATO which was established in 1949 under the Truman Doctrine. In 1954 the Modified Brussels Treaty transformed the Western Union into the Western European Union (WEU). West Germany eventually joined both the WEU and NATO in 1955, prompting the Soviet Union to form the Warsaw Pact in 1955 as an institutional framework for its military domination in the countries of Central and Eastern Europe. Assessing the progress of European integration the Messina Conference was held in 1955, ordering the Spaak report, which in 1956 recommended the next significant steps of European integration.