The Wall Around EU Fundamental Freedoms: the Purely Internal Rule at the Forty-Year Mark

‘Purely internal situations’ are sets of facts entirely confined within a single Member State. According to the ‘purely internal rule’, introduced by the European Court of Justice (ECJ) in 1979, purely internal situations lie outside the scope of the internal market fundamental freedoms and of other EU provisions having a cross-border scope. On the fortieth anniversary of the jurisprudential genesis of the purely internal rule, this article seeks to examine its origins, rationale, and evolution, by analyzing the most relevant patterns in the over 250 preliminary rulings handed down in disputes involving purely internal situations. This survey will enable an assessment of the systemic significance of the purely internal rule and of the consequences that abolishing that rule would have for the European integration process.