This is the final lesson of the macro topic, “Concepts and Categories to Understand the EU and Its Development and Working,” in the first module of EUPress Teacher Training.
The objective of this lesson, led by Pietro Sala, is to discuss the European constitutionalism.
The European Union may not have been born with a constitution, but over time it has developed something very close to one — not through political conventions or popular referendums, but through the steady work of judges and law. This process, known as European constitutionalism, has reshaped the EU’s legal order far beyond what its founding treaties originally implied.
From federal dreams to judicial reality
In the early postwar years, European federalists argued for a fully-fledged constitution to create a “United States of Europe.” But with nationalist resistance and political caution prevailing, that vision gave way to a gradualist and functionalist path — building integration sector by sector instead of through a single constitutional leap.
For decades, the term “European constitutionalism” disappeared. When it resurfaced, it referred not to a founding document, but to the judicial and legal transformation of the European Community into a quasi-constitutional system.
The Court of Justice as Europe’s constitutional engine
The European Court of Justice (ECJ) played a role comparable to the U.S. Supreme Court after the American federation was established in 1787. Through a series of historic rulings beginning in the 1960s, the ECJ established fundamental principles that gave the EU legal order its autonomy — and supremacy.
Key rulings included:
- Van Gend en Loos (1963) — affirmed the direct effect of EU law, meaning individuals can invoke EU rules in national courts without national implementation.
- Costa v ENEL (1964) — established the supremacy of EU law over national law, even in cases of conflict.
- Simmenthal (1978) — clarified that national courts must disapply conflicting national laws, even if newer than EU legislation.
- Implied powers doctrine — affirmed that the Union may act beyond explicit treaty bounds where necessary to achieve treaty objectives.
- Cassis de Dijon (1979) — introduced the principle of mutual recognition, preventing protectionism through national standards within the internal market.
These rulings functioned as a silent constitutional revolution, giving the Community its own legal hierarchy, applicable not only to states but to citizens and companies — effectively transforming a treaty-based international organisation into a legal and political system of its own.
A legal order with constitutional force
Legal scholars like Joseph Weiler argue that the EU now has an implicit constitution: a hierarchical legal system capable of limiting national legislative powers and granting rights and duties to individuals. This evolution has redefined the way European integration is studied — no longer as a niche of international law, but as a central subject for constitutional and legal theory.
Thanks to judicial activism, the EU today resembles a federal system in its operation — even if it still lacks a single written constitution. And as legislative reforms continue to expand EU competences, especially in areas like the single market, digital regulation, and climate policy, that constitutional reality grows more pronounced.
European constitutionalism didn’t begin with a founding assembly or a constitutional text. It evolved case by case, judgment by judgment — showing that in Europe, law has often led where politics feared to go.
