How the European Union Works: Structure, Powers, and Membership

What Is the European Union?

The European Union is a unique political and economic union of 27 member states located primarily in Europe. It was established by the Maastricht Treaty in 1993, though its roots go back to the post-World War II integration project that began with the European Coal and Steel Community in 1951. The EU represents the most advanced experiment in voluntary supranational governance in history — a group of sovereign nations that have pooled significant aspects of their sovereignty in common institutions and agreed to be bound by a common body of law.

The EU has a single market allowing the free movement of goods, services, capital, and people across member states. Nineteen of the 27 member states share a common currency, the euro, managed by the European Central Bank. The EU negotiates international trade agreements on behalf of all members, coordinates foreign policy, and has expanded into areas like defense cooperation, migration management, and artificial intelligence regulation.

Understanding the EU requires grasping a fundamental tension that runs through its entire history: the tension between integration (pooling more sovereignty in supranational institutions) and intergovernmentalism (preserving national sovereignty and limiting the EU's powers). Every major crisis — the financial crisis of 2008–2012, the refugee crisis of 2015–2016, Brexit, COVID-19, and Russia's invasion of Ukraine — has forced this tension to the surface and produced both new integration and powerful resistance to it.

The Main EU Institutions

The European Commission is the EU's executive body and the guardian of the EU treaties. It has the sole right to propose EU legislation, enforces EU law against member states that violate it, and represents the EU in international trade negotiations. The Commission consists of one Commissioner from each member state, led by the President of the European Commission. Commissioners are supposed to act in the EU's interest, not their member state's, though this norm is imperfectly observed.

The European Parliament is the directly elected legislative body of the EU, with 720 members (MEPs) elected by proportional representation in their home countries every five years. The Parliament shares legislative power with the Council of the EU and exercises democratic oversight over the Commission, including the power to censure and dismiss the Commission by a two-thirds majority. Though it lacked real power in the EU's early decades, successive treaty reforms have substantially increased Parliament's legislative role.

The Council of the European Union (also called the Council of Ministers) represents the governments of member states. Ministers from each member state meet in different configurations depending on the subject — finance ministers for economic issues, foreign ministers for foreign policy, etc. Most decisions are taken by qualified majority voting (QMV), requiring 55% of member states representing 65% of the EU's population. Some sensitive areas — foreign policy, taxation, constitutional changes — still require unanimity, giving each member state a veto.

The European Council and the ECJ

The European Council, distinct from the Council of the EU, brings together the heads of government (and heads of state) of all member states to set the EU's overall political direction. It meets several times per year in summits that produce the political deals and compromises underlying EU policy, particularly on sensitive issues where ministerial-level negotiations have stalled. The European Council President chairs these meetings.

The Court of Justice of the European Union (ECJ or CJEU) ensures uniform interpretation and application of EU law across all member states. Its rulings are binding on national courts, and it can find member states in violation of EU law and impose financial penalties. The ECJ's doctrine of the supremacy of EU law over national law — a doctrine the Court itself developed in the 1960s rather than one explicitly written in the treaties — is one of the most politically contentious aspects of EU membership, particularly in countries with strong constitutional courts like Germany and Poland.

The European Central Bank (ECB) manages the euro and conducts monetary policy for the eurozone. The ECB's mandate focuses on price stability, and it operates independently of political control — a design choice reflecting the German Bundesbank model and German insistence on monetary discipline. The ECB's role expanded dramatically during the 2012 eurozone debt crisis when President Mario Draghi's pledge to do "whatever it takes" to preserve the euro effectively committed the ECB to acting as lender of last resort.

The Single Market and the Euro

The EU's single market — formalized by the Single European Act of 1986 — is the world's largest trading bloc by GDP. It eliminates tariffs and most non-tariff barriers on trade between member states, allowing goods to circulate freely. The "four freedoms" — free movement of goods, services, capital, and people — define the single market. Any EU citizen has the right to live and work in any other EU member state, a transformation of European identity with profound social and political consequences.

Harmonization of regulations — ensuring that products meet common standards across the EU — is one of the single market's main mechanisms. When the EU adopts a product standard or safety regulation, it applies across all 27 countries, creating the "Brussels effect": because any company wanting access to the EU's 450-million consumer market must meet EU standards, the EU de facto exports its regulations globally. This regulatory power has made the EU a major player in areas like data privacy (GDPR), food safety, and environmental standards.

The euro, introduced as a currency in 1999 (physical notes and coins in 2002), was designed to complete the single market by eliminating currency exchange costs and risks. However, the eurozone's design — common monetary policy but separate fiscal policies — proved problematic during the 2010–2015 debt crisis. Countries like Greece, Portugal, and Ireland could not devalue their currencies to regain competitiveness; instead they faced brutal austerity. The subsequent debate about "fiscal union" — creating common fiscal instruments to complement monetary union — continues to reshape European politics.

Membership, Enlargement, and Brexit

EU membership requires meeting the Copenhagen Criteria, established in 1993: stable institutions guaranteeing democracy, the rule of law, human rights, and protection of minorities; a functioning market economy; and the ability to take on the obligations of membership, including implementing the entire body of EU law (acquis communautaire). Countries go through a prolonged accession process involving screening, negotiating chapters of law, and ultimately a unanimous vote of existing members.

The EU has expanded from six founding members to 27, most recently admitting Croatia in 2013. Several countries are currently candidate countries, including Ukraine, Moldova, and Western Balkan nations. Each enlargement has changed the EU's character — the 2004 expansion to include ten Central and Eastern European countries was the largest in history, nearly doubling membership and shifting the EU's political center of gravity eastward.

Brexit — the United Kingdom's departure from the EU, formally completed on January 31, 2020 — was the first case of a member state leaving. The 2016 referendum result (52% for leaving) and the subsequent years of fractious negotiations revealed both the complexity of disentangling a major economy from EU membership and the depth of political divisions over sovereignty, immigration, and national identity. Brexit's long-term consequences — for the UK, for EU unity, and for the future of integration — continue to unfold and remain genuinely contested.

Current Challenges and the Future of European Integration

The EU faces a set of interconnected challenges that test the limits of its institutional design and political solidarity. The rise of Eurosceptic and populist parties across multiple member states — in Hungary, Poland, Italy, France, and elsewhere — reflects popular frustration with EU policies on immigration, cultural identity, and economic inequality. Hungary under Viktor Orbán has put the EU's rule-of-law enforcement mechanisms under sustained pressure, creating a test case of what happens when a member state systematically dismantles democratic institutions.

Russia's invasion of Ukraine in 2022 forced a degree of geopolitical solidarity that surprised many observers — the EU imposed successive rounds of sanctions, provided substantial economic assistance to Ukraine, and took historic steps like providing lethal military aid. The prospect of Ukrainian membership has accelerated EU enlargement policy, though the institutional reforms needed to absorb Ukraine into the current EU architecture remain unresolved.

The climate crisis, the digital transformation, and the need to develop a European industrial policy in the face of American and Chinese competition have pushed the EU toward new areas of competence and spending. The NextGenerationEU fund, established in response to COVID-19 as a €750 billion recovery instrument financed by joint EU debt, marked a historic step toward fiscal integration that would have seemed impossible a decade earlier. Whether this represents a permanent shift toward deeper integration or a temporary crisis response remains the central question of European politics.