To gain a better understanding about the basic principles and mechanism of the Court of Justice of the European Union it is important to mention CJEU’s main role which is, ‘ensuring EU law is interpreted and applied the same in every EU country; ensuring countries and EU institutions abide by EU law.’ To put it broadly, the Court of Justice is interpreting the law where necessary for national courts, enforcing the law where failing to comply with the EU law, annulling legal acts where it is believed to violate the EU Treaties. In addition to that the Court of Justice also has to ensure that the EU takes action using other bodies such as the Parliament, Council or Commission. And last but crucially, the CJEU takes sanctions on EU institutions as a result of the disputes brought to court where one or more parties had their interests affected.
In order to have a good functionality in a system composed of multiple bodies, the set of rules of one body must comply with the set of rules of another. In this case the national law of a member state, needs to be in line with the EU law. But what happens when it is not? Which side would prevail and why? ‘The EC Treaty is silent on the question of priorities between Community law and national law. In ordinary international law the constitutional rules of a country determine whether international agreements can take precedence over national law.’
The first example of a case law which answers the first question promptly and where a conflict between the national law and the EU law occurred, is the Van Gend en Loos case in 1962. The ECJ clearly stated that ‘the Community constitutes a new legal order in international law, for whose benefit the States have limited their sovereign rights, albeit within limited field’. It is no doubt at this stage that the EU law has supremacy over the national law when the two are in conflict. However, the requirement for the Member State to limit its own sovereignty is not an obligation to nullify the law. The national law will continue to have the same binding effect as long as it is not in direct conflict with the EU law.
A second example where the doctrine of the supremacy of the Court of Justice was in forefront is in the case of Flaminio Costa v ENEL. Here the Court clearly states that, ‘By contrast with ordinary international treaties, the EEC Treaty has created its own legal system which, on the entry into force of the Treaty, became an integral part of the legal systems of the Member States and which their courts are bound to apply.’ Having established already that the EU law has the supremacy in report to the national law, the Court of Justice brings its arguments to justify its position. One and probably most obvious is contractarian suggesting it as part of the agreement signed by the Member States when joining the EU. Another aspect which favours the EU supremacy is the good functionality of the European Union. When a single Member State will not be giving effect to the EU law, the aims of the Treaty would not be achieved. This leads to a third argument stating that if a Member State would take supremacy over the EU law, it would create a precedent which would lead to discrimination between Member States.
By reviewing the CJEU’s decisions in the cases above mentioned and establishing the supremacy and the arguments brought by the Court itself regarding its doctrine, the basic questions raised above have been addressed already. However, it does leave room to question the direct impact and efficiency this hierarchy has on Member States which further results to the ongoing mechanism of the EU.
It is difficult to discuss about the CJEU’s doctrine of supremacy without at least mentioning probably the currently most controversial topic which is related to the EU’s influence on Member States, Brexit. Maintaining the focus on the judicial aspect it is fair to mention that one of the reasons that led to a majority of the UK citizens to vote ‘leave’ the EU is precisely the ‘stretched control’, the EU has had over the UK. Without analysing the authenticity of the motif it is natural to raise a question: Where to draw the line between legal supremacy and absolute control? The European Union currently consists of a large variety of component states in terms of internal development. It is therefore likely to have a disequilibrium among different Member States and them perceiving the benefits and burdens of the EU and the CJEU’s influence in their internal development. ‘Smaller countries could be squeezed out or opt to leave the economic bloc in the wake of the EU referendum in Britain, after the public voted to leave the union.’
The supremacy doctrine of the Court of Justice of the EU is aimed according to Article 3a of the Treaty of Lisbon to, ‘respect the equality of Member States before the Treaties as well as their national identities.’ In contrast with the American law where the authority of the United States is the ‘supreme law of the land’, the CJEU has to deal with the objective of a uniform integration of all Member States concerning their internal development which has yet to be achieved. Having a more balanced equilibrium between Member States of the Community, the Court of Justice can apply its supremacy doctrine avoiding the inequality perceived by certain Member States.
 ‘Court Of Justice Of The European Union (CJEU) – European Union Website, The Official EU Website – European Commission’ (European Union website, the official EU website – European Commission, 2016) <https://europa.eu/european-union/about-eu/institutions-bodies/court-justice_en> accessed 12 October 2016.
 <http://www.austlii.edu.au/au/journals/IntTBLawRw/2004/8.html> accessed 13 October 2016.
 P. P Craig and G De Búrca, EU Law.
 Flaminio Costa v ENEL,  ECR 585.
 ‘Too Much EU Interference? A Look At The Areas Where Critics Say The Single Market Overreaches Itself’ (LSE BREXIT, 2016) <http://blogs.lse.ac.uk/brexit/2016/01/28/too-much-eu-interference-a-look-at-the-areas-where-critics-say-the-single-market-overreaches-itself/> accessed 13 October 2016.
 Vickiie Oliphant, ‘Putin Says Brexit Could See EU COLLAPSE – As Leader Reveals He’s Ready For UK Dialogue’ (Express.co.uk, 2016) <http://www.express.co.uk/news/world/706813/Brexit-precedent-collapse-EU-eurozone-Vladimir-Putin> accessed 13 October 2016.
 ‘EUR-Lex – 12007L/TXT – EN – EUR-Lex’ (Eur-lex.europa.eu, 2016) <http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:12007L/TXT> accessed 14 October 2016.
 ‘Article VI’ (LII / Legal Information Institute, 2016) <https://www.law.cornell.edu/constitution/articlevi> accessed 14 October 2016.
AUTHOR: M. Benec