Introduction
The free movement of goods is a cornerstone of the European Union's single market, designed to eliminate trade barriers between Member States and foster economic integration. The principle, enshrined primarily in Article 34 of the Treaty on the Functioning of the European Union (TFEU), prohibits quantitative restrictions on imports and all measures having equivalent effect (MEQRs). However, the EU project has never demanded the complete erosion of a Member State’s ability to regulate its own territory in the public interest. The EU treaties and the case law of the Court of Justice of the European Union (CJEU) therefore provide a system of justifications that permit Member States to maintain national rules which restrict trade, provided they pursue a legitimate aim and are proportionate. This essay will critically evaluate the extent to which this system, particularly the approach to justifications and proportionality, gives Member States adequate room to regulate. It will be argued that while the CJEU has developed a flexible framework for recognising legitimate public interests, its strict application of the proportionality test significantly constrains Member State policy choices, arguably prioritising market integration over national regulatory autonomy to a degree that may not always be considered 'adequate'.
The Wide Net of Article 34 TFEU
To understand the importance of justifications, one must first appreciate the breadth of the prohibition they seek to derogate from. Article 34 TFEU prohibits MEQRs, a concept which the CJEU defined in the landmark case of Dassonville. The Court stated that "all trading rules enacted by Member States which are capable of hindering, directly or indirectly, actually or potentially, intra-Community trade are to be considered as measures having an effect equivalent to quantitative restrictions" (Case 8/74 Procureur du Roi v Dassonville [1974] ECR 837). This incredibly broad formula captures a vast range of national rules, from product standards and packaging requirements to advertising restrictions. By catching not only discriminatory measures but also those which apply equally to domestic and imported goods (indistinctly applicable measures), the Dassonville formula places a significant number of domestic regulations under the scrutiny of EU law.
This wide scope makes the system of justifications essential. Without it, Member States would be unable to legislate on many matters of public concern, such as environmental protection or public health, if their rules had any potential to affect trade flows. The central question, therefore, is not whether justifications can exist, but whether the framework for applying them provides a reasonable balance.
The Framework of Justifications
The CJEU has recognised two main avenues for justifying a measure that falls within the scope of Article 34 TFEU: the express derogations listed in Article 36 TFEU, and the judicially created 'mandatory requirements' originating from Cassis de Dijon.
Article 36 TFEU provides an exhaustive list of non-economic public interests for which a Member State may restrict trade. These include public morality, public policy, public security, the protection of health and life of humans, animals or plants, and the protection of national treasures. Because these derogations are exceptions to a fundamental freedom, the CJEU interprets them strictly. For instance, in R v Henn and Darby (Case 34/79 [1979] ECR 3795), a UK ban on pornographic material was upheld on public morality grounds, but in Conegate v HM Customs & Excise (Case 121/85 [1986] ECR 1007), a ban on importing inflatable dolls from Germany was not justified because similar items were lawfully manufactured in the UK, showing the measure was arbitrary. Article 36 can be used to justify both distinctly and indistinctly applicable measures, but its closed list provides limited flexibility for Member States wishing to pursue policy goals not enumerated in the treaty.
The more significant development in affording Member States regulatory space came in Rewe-Zentral AG v Bundesmonopolverwaltung für Branntwein (Case 120/78), commonly known as Cassis de Dijon [1979] ECR 649. The case concerned a German law that set a minimum alcohol level for liqueurs, preventing the importation of a French crème de cassis which had a lower alcohol content. The CJEU established what became known as the 'rule of reason', stating that, in the absence of EU-wide harmonisation, obstacles to free movement resulting from disparities between national laws could be accepted provided that the rules were necessary to satisfy "mandatory requirements". This created an open-ended list of legitimate public interests that could justify indistinctly applicable MEQRs. Over the years, the CJEU has recognised various mandatory requirements, including consumer protection (Cassis de Dijon), environmental protection (Case C-2/90 Commission v Belgium (Walloon Waste) [1992] ECR I-4431), and the fairness of commercial transactions.
On the surface, the creation of mandatory requirements appears to greatly enhance the regulatory autonomy of Member States. It allows them to pursue a wide range of public policy objectives beyond the confines of Article 36, reflecting an understanding that modern states have complex regulatory needs. This judicial creativity suggests a willingness to give Member States considerable room to legislate. However, the availability of a legitimate aim is only the first step; the measure must also survive the proportionality test.
Proportionality: The Real Constraint on Member State Autonomy
Any measure a Member State seeks to justify, whether under Article 36 or the mandatory requirements, must be proportionate to the aim pursued. The proportionality test, as applied by the CJEU, is a rigorous two-part assessment: first, the measure must be suitable to achieve the objective, and second, it must be necessary, meaning it must be the least restrictive of trade among available options that could achieve the same objective (Chalmers et al., 2019). It is the necessity limb of this test which most significantly curtails the regulatory space of Member States.
The CJEU’s application of the necessity test often involves it substituting its own judgment for that of a national government. The Court scrutinises whether alternative, less trade-restrictive measures could have been employed. A classic example is the Commission v Germany (German Beer Purity) case (Case 178/84 [1987] ECR 1227). Germany banned beers containing additives, citing public health and consumer protection. The CJEU rejected these justifications as disproportionate. It held that the public health risk was not established and that consumer protection could be achieved through a less restrictive means, such as clear labelling. By dictating that labelling was a sufficient alternative to a ban, the Court effectively overruled Germany’s policy choice about the appropriate level of health and consumer protection.
Similarly, in cases concerning advertising restrictions, the CJEU has frequently found total bans to be disproportionate. In De Agostini (Joined Cases C-34/95 to C-36/95 [1997] ECR I-3843), Sweden’s complete ban on television advertising directed at children under 12 was scrutinised. The Court concluded that while protecting children was a legitimate mandatory requirement, it was for the national court to determine whether a total ban was necessary or if less restrictive measures could provide sufficient protection. This approach places a heavy burden of proof on the Member State to demonstrate that no other conceivable policy could work, a standard which can be difficult to meet.
This strict interpretation of necessity means that even when a Member State is pursuing a universally accepted public good, its chosen method is vulnerable to being struck down if the CJEU can identify a hypothetical, less trade-restrictive alternative. Critics argue this leads to a form of judicial activism where the Court is not merely policing the boundaries of EU law but is actively involved in national policy-making, prioritising the abstract goal of a frictionless single market over the concrete policy choices of democratically elected governments (Craig and de Búrca, 2020). The concept of 'adequacy' implies a fair balance, yet this approach suggests the balance is structurally tilted in favour of market integration.
Conclusion
The statement that Member States are entitled to restrict free movement in pursuit of legitimate public interests is certainly true in principle. The CJEU has provided two main routes for justification: the treaty-based list in Article 36 and the open-ended mandatory requirements developed since Cassis de Dijon. The latter, in particular, demonstrates a judicial willingness to accommodate the diverse regulatory needs of Member States. However, the critical evaluation of the extent to which this provides 'adequate' room for manoeuvre reveals a more complex reality.
The key limitation on Member State autonomy is the CJEU’s stringent application of the proportionality principle, especially the necessity test. By requiring national governments to prove their chosen policy is the least trade-restrictive option available, the Court significantly narrows their scope for action. This judicial review often feels less like an assessment of legality and more like a reassessment of policy desirability. While this approach has been instrumental in breaking down protectionist barriers disguised as public interest regulation, it has also challenged legitimate national choices regarding the desired level of protection for consumers, the environment, or public health. Therefore, while the EU legal order provides the grounds for justification, the method of scrutiny applied by the CJEU ensures that the room for Member States to regulate in the public interest is often narrow, closely supervised, and ultimately subordinate to the primary objective of creating and maintaining the single market. Whether this room is 'adequate' remains a point of contention, but from the perspective of national sovereignty and policy-making, it is undeniably limited.
References
Chalmers, D., Davies, G. and Monti, G. (2019) European Union Law: Text and Materials. 4th edn. Cambridge: Cambridge University Press.
Craig, P. and de Búrca, G. (2020) EU Law: Text, Cases, and Materials. 7th edn. Oxford: Oxford University Press.
Case Law
Case 121/85 Conegate v HM Customs & Excise [1986] ECR 1007.
Case C-2/90 Commission v Belgium (Walloon Waste) [1992] ECR I-4431.
Case 178/84 Commission v Germany (German Beer Purity) [1987] ECR 1227.
Joined Cases C-34/95 to C-36/95 De Agostini [1997] ECR I-3843.
Case 8/74 Procureur du Roi v Dassonville [1974] ECR 837.
Case 34/79 R v Henn and Darby [1979] ECR 3795.
Case 120/78 Rewe-Zentral AG v Bundesmonopolverwaltung für Branntwein (Cassis de Dijon) [1979] ECR 649.
Legislation
Consolidated Version of the Treaty on the Functioning of the European Union [2012] OJ C326/47.
