How the European Union Actually Works

On the evening of October 17, 2019, negotiators emerged from the Justus Lipsius building in Brussels, the gray fortress of offices where the heads of European governments meet, to announce that the EU's 27 remaining members and the United Kingdom had agreed on a revised Brexit Withdrawal Agreement. It had taken more than three years since the British referendum, several collapsed deals, two prime ministers, and an extraordinary amount of late-night drafting to reach that point. The scene captured something essential about the Union: a continent that had spent the first half of the twentieth century tearing itself apart was now spending its evenings arguing, in painstaking legal detail, about the terms under which one of its members could leave.

That image cuts against the two most common misconceptions about the European Union. It is not a superstate that overrides its members at will, and it is not a loose trade club whose decisions are merely advisory. It is something stranger, and to understand it you have to understand how its institutions are wired together. This article walks through what the EU is, how it actually makes law, where its power genuinely bites, and what the long Brexit drama exposed about the whole arrangement.

A Union built treaty by treaty, not at a single founding

The European Union is the deepest political integration ever attempted among formerly sovereign states, and it was assembled gradually, through a sequence of treaties that began in the early 1950s rather than at one constitutional moment. There was no Philadelphia convention for Europe, no single dramatic signing that conjured a federation into being. Instead the project advanced in deliberate steps, each one a bargain among governments that agreed to hand a particular slice of authority to common institutions.

The earliest of those steps grew directly out of the wreckage of the Second World War. The original idea was almost devious in its modesty: bind together the coal and steel industries of France and West Germany, the very materials of war, so tightly that another conflict between them would become not just unthinkable but mechanically impossible. From that narrow industrial pact the project widened, treaty by treaty, into a common market, then a single currency for many members, then cooperation on everything from environmental standards to policing. The crucial point is that every expansion of the EU's reach required member governments to sign a new treaty, which means the Union's powers are not self-granted. They are delegated, and in principle they can be withdrawn, a fact that Brexit would later prove concretely.

The institutional triangle that turns proposals into law

At the center of the EU sits an arrangement often described as the institutional triangle, and once you grasp it the rest of the system becomes legible. Three bodies share the work of legislating, each playing a distinct role.

The first is the European Commission, the EU's executive arm, staffed by appointed commissioners and a large civil service. The Commission holds a power that is easy to underestimate: in most areas it alone can propose new EU law, since neither the Parliament nor the member states can simply table a bill on their own initiative. This monopoly on proposal makes the Commission the agenda-setter of the entire Union. The second body is the European Parliament, directly elected by citizens across the member states, which sits as one of the two co-legislators. The third is the Council of the European Union, sometimes called the Council of Ministers, where the relevant national ministers from each member government meet to represent their countries' interests; it is the other co-legislator.

A typical law moves through this triangle in a recognizable sequence. The Commission drafts and proposes, and then the Parliament and the Council must both agree, amending the text and negotiating until they reach a common position, before it can take effect. Lawmaking therefore runs through the Commission's proposals and the joint authority of the Council and the Parliament. Standing slightly apart from this machinery is a fourth institution, the European Council, which is not the same body as the Council of Ministers despite the confusingly similar name. The European Council is the summit of heads of state and government themselves, and its job is not to grind through individual statutes but to set the Union's overall political direction, defining priorities and brokering the largest bargains. It was the European Council that gathered in Brussels in 2019 to sign off on the Brexit deal.

Half supranational, half intergovernmental, and deliberately so

The genius and the frustration of the EU both come from the same design choice. The Union is a hybrid, mixing two opposed logics that political scientists call supranational and intergovernmental, and it never fully resolves the tension between them.

The supranational features are the parts of the EU that stand above the member states and can bind them even against their will. The Commission, the directly elected Parliament, and above all the Court of Justice of the European Union belong to this category. The Court's role is especially powerful, because it can rule that a national law violates EU law and require that the national law give way, a principle of legal primacy that genuinely constrains what governments may do at home. These bodies make the EU something more than the sum of its members, an order with an authority of its own.

The intergovernmental features pull in the opposite direction. The Council of Ministers and the European Council are arenas where member states retain their authority and bargain as sovereign governments, each guarding its national interest, and on the most sensitive matters a single country can often block a decision outright. The result is a system that is constantly negotiating the boundary between supranational authority, where common institutions decide for everyone, and intergovernmental control, where nation-states keep the final say. Most of the EU's recurring dramas, from budget fights to migration disputes, are really arguments about where that boundary should lie.

Where the Union's power actually bites

It is one thing to describe institutions and another to ask where they matter in practice, and here the picture is uneven by design. The EU's influence is most consequential in a handful of areas, and comparatively thin in others.

The deepest integration is the single market, the project of letting goods, services, capital, and people move across internal borders as if the Union were one economy. This is where EU rules touch ordinary life most directly, governing product standards, professional qualifications, and the right of a citizen of one member state to live and work in another. Closely tied to it is monetary policy for the subset of countries that adopted the euro, whose interest rates and currency are managed centrally by the European Central Bank rather than by national governments. Trade is a third domain of real power, since the EU negotiates as a single bloc with the rest of the world, which gives it far more leverage than any member would have alone. Environmental policy is a fourth, with binding common standards on emissions, pollution, and conservation. The fifth area, cooperation on migration and home affairs, is substantial but genuinely contested, the part of the system where members most visibly disagree about how much authority to pool. Outside these domains, in matters such as taxation, healthcare, and most of social policy, the EU's role thins out and national governments remain firmly in charge.

From six founding members to twenty-seven, and the awkward British case

The Union that exists today is far larger than the one that began. It started with six members and grew, through successive rounds of enlargement, to twenty-seven. Each enlargement was a deliberate decision, an existing membership voting to admit new states that had to meet democratic and economic conditions to join, and each one changed the character of the club.

The United Kingdom's accession in 1973 was a pivotal early enlargement, and in hindsight it also established a pattern of half-hearted membership that ran through Britain's entire time in the Union. The UK joined late, having stayed out of the founding bargains, and it negotiated opt-outs that kept it apart from some of the deepest commitments, declining the euro and parts of the borderless travel arrangements. Britain was, in a sense, always a reluctant member, in the project but never wholly of it, and that ambivalence eventually culminated in the decision to leave. The story of enlargement is therefore not just one of expansion but of varying depth.

The democratic deficit and the case of leaving

No account of how the EU works is honest without confronting the most persistent criticism leveled against it, the charge of a democratic deficit. The argument holds that the Union's institutional architecture lacks adequate democratic accountability, that too much power rests with appointed officials and distant negotiations rather than with directly elected representatives answerable to voters. Critics point to the Commission's unelected commissioners, to decisions reached in opaque late-night Council sessions, and to the difficulty an ordinary citizen faces in tracing who exactly is responsible for a given EU rule. Defenders counter that the Parliament is directly elected, that national ministers in the Council answer to their own electorates, and that the Union is more accountable than its critics allow. The dispute is genuine and unresolved, and it matters because this perceived gap is a large part of what fuels Euroscepticism, the political mobilization against deeper integration that has grown across many member states.

That mobilization produced the Union's hardest test. Britain's 2016 referendum, the grinding negotiations from 2017 through 2019, and the eventual departure in 2020 together formed a stress test of whether the EU's institutions could manage a member state's withdrawal under sustained political pressure. The process was painful and revealing. It exposed the real costs of leaving, the tangle of trade, legal, and border complications that unwinding decades of integration entails, and it demonstrated, perhaps to the EU's own surprise, that the Union could hold together through the ordeal without fracturing. Crucially, watching how difficult and costly the British exit proved to be helped explain why no other member state has seriously moved to follow. Brexit did not trigger a cascade; if anything, it dampened the appetite for departure.

A continent still under pressure

The EU that absorbed Brexit did not emerge into calm. The contemporary Union faces a cluster of serious pressures at once. There is rule-of-law backsliding inside some member states, where national governments have weakened the independence of courts and the press in ways that clash with the democratic standards membership is supposed to guarantee. There is sustained migration pressure on the Union's external frontiers, which keeps reopening the unresolved question of how to share responsibility. There are the energy and security shocks that followed the war that began in 2022, which forced the EU to rethink its dependence on imported energy and the adequacy of its common defense. And there are contested decisions about further enlargement, about which countries to admit and on what terms.

These strains are precisely why the EU remains the most valuable case study in the world for one of the deepest questions in political science: whether and how sovereignty can be pooled durably across formerly independent states. No other contemporary arrangement attempts integration so deep among so many countries that were once rivals and enemies, and so its successes and failures alike teach lessons that no smaller or shallower union could.

Key Takeaways

The European Union is the deepest political integration ever attempted among formerly sovereign states, built incrementally through treaties since the early 1950s rather than founded at a single moment, and it works through an institutional triangle in which the Commission alone proposes legislation while the directly elected Parliament and the member-state Council jointly enact it, with the European Council of national leaders setting overall direction; the whole system is a deliberate hybrid of supranational features (the Commission, Parliament, and Court of Justice, which can bind members) and intergovernmental ones (the two Councils, where states retain authority), and its power bites hardest in the single market, the euro and monetary policy, trade, environmental standards, and the contested area of migration. Having grown from six members to twenty-seven, the Union carries a persistent democratic-deficit critique that fuels Euroscepticism, and it survived the severe stress test of Brexit, the 2016 referendum through the 2020 departure, without losing coherence, an outcome whose evident costs help explain why no other member has seriously sought to leave; today it confronts rule-of-law backsliding, migration, post-2022 energy and security shocks, and contested enlargement, remaining the world's deepest living laboratory for testing whether sovereignty can be pooled durably across once-independent states.