European Court of Justice
60% of cases arrive as questions from national courts. Developed supremacy and direct effect doctrines that made EU integration legally irreversible. 27 judges interpret law that binds 450 million people.
Sixty percent of cases arrive as questions, not disputes. A national court in Lisbon or Helsinki encounters EU law it cannot interpret, stops proceedings, and sends questions to Luxembourg. The European Court of Justice answers—and its answer binds every court in every member state. This preliminary reference procedure transformed a trade agreement into a constitutional order.
The ECJ developed two doctrines that made European integration legally irreversible: direct effect and supremacy. Direct effect meant individuals could invoke EU law in national courts—no implementing legislation required. Supremacy meant EU law trumps conflicting national law—always, automatically, no exceptions. Neither doctrine appears in the treaties. The Court constructed them through case law, creating constitutional architecture that the politicians who signed the treaties never explicitly authorized. Path-dependence through judicial interpretation.
Twenty-seven judges sit in Luxembourg, one from each member state, appointed for renewable six-year terms. The Court operates through costly-signaling: judgments carry weight because reversing them requires treaty amendment (unanimous consent of all members). This irreversibility makes each ruling a credible commitment. Poland and Hungary discovered this when rule-of-law disputes reached the Court—ECJ judgments found violations, but the political will to enforce them remained contested.
The coalition-formation function extends beyond dispute resolution. When the Court interprets a directive broadly, it harmonizes law across 27 legal systems simultaneously. When it finds a member state in violation, it signals what compliance requires. The organism shapes behavior through interpretation as much as enforcement—precedent constrains future action even without sanctions.
Since October 2024, the General Court shares preliminary ruling jurisdiction in specific areas—the first structural change in decades. The organism adapts to caseload pressure by specializing organs.
The biological lesson: legal systems that can generate binding interpretations create coordination mechanisms that contracts and treaties alone cannot. The ECJ doesn't just resolve disputes; it produces the common understanding that makes a 27-nation legal system possible. Without a supreme interpreter, EU law would fragment into 27 national variations. The Court is the mechanism that prevents drift.
Neither supremacy nor direct effect—the doctrines that made EU law superior to national law—appear in the treaties. The Court constructed them through case law in the 1960s (Van Gend en Loos 1963, Costa v ENEL 1964), creating constitutional architecture the treaty signers never explicitly authorized.
Key Facts
Power Dynamics
Final interpreter of EU law; preliminary rulings bind all national courts; can find member states in violation; can annul EU legislation
Supremacy doctrine means ECJ interpretations override national law automatically; preliminary reference procedure gives Court control over how EU law develops; rule-of-law enforcement against Poland/Hungary shows limits when political will to sanction is absent
- Treaty amendment (unanimous) can override judgments
- Member state non-compliance (limited enforcement mechanisms)
- National constitutional courts occasionally resist supremacy claims
- European Commission (brings infringement cases)
- National courts (preliminary reference requesters)
- National constitutional courts (occasional supremacy disputes)
- Council of the EU (rule-of-law enforcement requires political action)
Failure Modes of European Court of Justice
- Polish Constitutional Tribunal 2021 - Ruled ECJ judgments unconstitutional, directly challenging supremacy
- German Constitutional Court 2020 - PSPP judgment questioned ECJ authority on monetary policy
- No enforcement mechanism independent of political will
- Rule-of-law disputes reveal limits when member states refuse compliance
- Caseload growth strains judicial capacity
- Supremacy claims face resistance from national constitutional courts
Multiple member states simultaneously reject ECJ authority, creating fragmentation that treaties cannot resolve without political consensus that no longer exists
Biological Parallel
The ECJ functions like the nervous system's interpretive center—receiving signals from distributed sensors (national courts), processing them against a common framework (EU law), and sending coordinated responses that align behavior across the entire organism. Without this central interpreter, the 27 member states would develop conflicting interpretations, like a body with 27 brains sending contradictory signals. The preliminary reference procedure is the afferent pathway; the binding judgment is the efferent response. The organism maintains coherence through interpretation.
Key Agencies
Highest court for EU law interpretation
First instance for direct actions, now shares preliminary rulings
Provide independent legal opinions before judgments