European Union

European integration took shape after the Second World War, when governments sought closer cooperation as a way to support recovery, security and lasting reconciliation. In 1951, Belgium, France, Italy, Luxembourg, the Netherlands and West Germany signed the Treaty of Paris, creating the European Coal and Steel Community. The Treaties of Rome, signed in 1957, established the European Economic Community and the European Atomic Energy Community. The Maastricht Treaty, signed in 1992 and effective from 1 November 1993, created the European Union and broadened cooperation beyond the earlier communities. Subsequent treaties and enlargements changed the Union's membership and institutions.

The EU acts through institutions established by its treaties, each with defined responsibilities. In the ordinary law-making process, the European Commission generally proposes legislation, while the directly elected European Parliament and the Council of the European Union—where national ministers represent their governments—consider and adopt laws. The European Council, made up of national leaders, sets broad political direction; it is distinct from the Council of the European Union. The Council of Europe is a separate international organization, not an EU institution. These arrangements combine representation of EU citizens with participation by member-state governments.

The treaties set out aims that include promoting peace and well-being, establishing an internal market, supporting economic and social development, and protecting the Union's values. The internal market is designed to allow the free movement of goods, people, services and capital among member countries, subject to the rules and exceptions in EU law. Cooperation also extends to fields such as trade, environmental protection, research and justice. The EU is not a unitary state: its powers and procedures are treaty-based, and different policy areas involve different forms of shared or national responsibility.

As of 2026, the EU has 27 member states. Membership does not mean that every country participates in every European arrangement in the same way: for example, the euro area and the Schengen area have their own membership, which is not identical to EU membership. The Union has also changed over time through successive accessions and the departure of the United Kingdom in 2020. It is therefore best understood as an evolving union of states with common institutions and rules, rather than as a country with a uniform system in every policy field.