The European Union is a political and economic union of 27 European countries that have agreed through treaties to exercise certain powers collectively and cooperate across a wide range of policy areas. It developed from post Second World War European cooperation and has become a distinctive form of regional integration combining intergovernmental and supranational features.
The EU was founded in its earlier institutional form in the 1950s by Belgium, France, Germany, Italy, Luxembourg and the Netherlands, and its membership subsequently expanded to 27 countries. The EU is not simply a conventional international organisation because its treaties establish institutions with defined powers to make, interpret, administer and enforce common rules.
At the same time, it is not a sovereign country because its member states remain independent states with their own constitutions, governments, territories, citizenship arrangements and international legal personalities. The EU therefore occupies a distinctive constitutional position between ordinary international cooperation and a fully centralised state.
The EU operates through a treaty based institutional system. Its seven principal institutions are the European Parliament, European Council, Council of the European Union, European Commission, Court of Justice of the European Union, European Central Bank and European Court of Auditors. The European Parliament represents EU citizens and participates in legislation and budgetary decisions. The Council of the European Union represents national governments through their ministers and generally adopts legislation jointly with Parliament.
The European Commission promotes the general interest of the EU, proposes legislation, manages policies and the budget and helps enforce EU law. The European Council, consisting of national leaders, establishes broad political direction rather than normally making legislation. The Court of Justice interprets EU law and ensures that the treaties and legislation are applied consistently. The institutional structure distributes authority rather than placing all power in a single European government.
One of the EU's most important economic achievements is its single market. Established in 1993, it is based on the free movement of goods, services, capital and people, commonly called the four freedoms. The single market seeks to reduce technical, legal and bureaucratic barriers that would otherwise divide national economies. It allows EU citizens under applicable rules to live, work, study and retire across member states and allows businesses to operate across national markets under common frameworks.
The EU also has a customs union, under which member states apply common customs arrangements to imports from outside the union. The euro provides a common currency for participating member states, although not all EU members use it. These arrangements demonstrate that membership does not mean every member state participates identically in every EU policy, because treaties contain different participation arrangements and some states have opt outs or remain outside particular integration projects.
EU powers are governed by the principle of conferral, meaning the Union can act only in areas where member states have authorised it through the treaties. The principles of proportionality and subsidiarity also influence how EU action is exercised. The EU has exclusive competence in specified fields such as the customs union, competition rules necessary for the single market and monetary policy for euro area countries, while other areas such as agriculture, fisheries, environment and aspects of the single market are shared between the EU and national governments.
This division is important because the EU does not possess unlimited general authority over member states. National governments remain responsible for many major areas of public administration, including most education, health, policing and taxation decisions, although EU law can affect particular aspects of those fields where treaty powers apply. EU membership therefore combines national government with collective European governance.
The historical development of the EU is rooted in efforts to create lasting cooperation among European states after two world wars. On 9 May 1950, French Foreign Minister Robert Schuman proposed placing French and West German coal and steel production under a common authority. The resulting European Coal and Steel Community was established by the 1951 treaty and involved Belgium, France, Germany, Italy, Luxembourg and the Netherlands.
The Treaties of Rome in 1957 established the European Economic Community and Euratom, expanding cooperation beyond coal and steel. Later developments included the Single European Act, the Maastricht Treaty, successive enlargements and the Lisbon Treaty. The Maastricht Treaty created the European Union as such and developed European citizenship and new areas of cooperation. The historical sequence illustrates how the EU developed incrementally through successive treaties rather than being created as a complete political system at one moment.
The EU's activities extend beyond trade. Its policy responsibilities and programmes cover areas including competition, agriculture, fisheries, regional development, research, environmental policy, consumer protection, digital regulation, transport, energy, justice and home affairs, international trade and aspects of foreign and security policy. The EU also operates a substantial budget through which it finances programmes and transfers resources according to collectively agreed priorities. Some policies are primarily European, some are shared with national governments and others are coordinated rather than centrally administered.
The EU's external role is also significant because its collective market size allows it to negotiate certain international agreements and trade arrangements. The European Commission, for example, represents the EU internationally in areas such as trade policy and negotiates international agreements within its treaty powers.
EU membership has legal and practical consequences for member states because common legislation, judicial decisions and treaty obligations become part of the framework within which national governments operate. EU law can regulate businesses and public authorities, establish rights for individuals and create common standards across national markets. The Court of Justice provides authoritative interpretations of EU law, while national courts apply EU rules within domestic legal systems where applicable.
This produces a multi level legal order in which European and national institutions interact. The system also creates continuing questions about democratic accountability, national sovereignty, distribution of powers and the appropriate level at which particular decisions should be made. These questions are inherent in a union that deliberately combines national self government with collective institutions rather than eliminating national political authority.
The EU is therefore best understood as a highly developed regional integration system rather than simply as a trade bloc. Its distinctive characteristics include a treaty based legal order, common institutions, a single market, shared policies, collective external action in specified areas and the ability of EU law to have legal effects within member states.
It is also important to distinguish the EU from Europe as a geographical concept, from the euro area, from the Schengen Area and from the Council of Europe, because these have different memberships and legal purposes. The EU currently contains 27 member states and nearly 450 million people, with its institutions and agencies distributed across Europe. Its development demonstrates how states can create durable common institutions while retaining national governments, constitutions and identities.
