European Union law primacy
(or supremacy) is a principle by which the laws of member states that conflict with valid laws of the European Union must be disapplied by the national courts. This doctrine, known as the supremacy of EU law, emerged from the European Court of Justice
through a number of decisions.
In Costa v. ENEL
. Mr Costa was an Italian citizen opposed to nationalising the Italian energy company ENEL, because he had shares in it. He refused to pay his electricity bill in protest, and argued that nationalisation infringed EC law on the State distorting the market. The Italian government believed that this was not even an issue that could
be complained about by a private individual, since it was a national law decision to make. The Court ruled in favour of the government, because the relevant Treaty rule on an undistorted market was one on which the Commission alone could challenge the Italian government. As an individual, Mr Costa had no standing to challenge the decision, because that Treaty provision had no direct effect. But on the logically prior issue of Mr Costa's ability to raise a point of EC law against a national government in legal proceeding before the courts in that Member State the ECJ disagreed with the Italian government. It ruled that EC law would not be effective if Mr Costa could not challenge national law on the basis of its alleged incompatibility with EC law.
It follows from all these observations that the law stemming from the treaty, an independent source of law, could not, because of its special and original nature, be overridden by domestic legal provisions, however framed, without being deprived of its character as community law and without the legal basis of the community itself being called into question.
Many countries' highest courts have stated that Community law takes precedence provided that it continues to respect fundamental constitutional principles of the Member State, the ultimate judge of which will be the Member State (more exactly, the court of that Member State), rather than the European Union institutions themselves This reflects the idea that Member States remain the "Master of the Treaties", and the basis for EU law's effect. In other cases, countries write the precedence of Community law into their constitutions. For example, the Constitution of Ireland contains a clause that, '"No provision of this Constitution invalidates laws enacted, acts done or measures adopted by the State which are necessitated by the obligations of membership of the European Union or of the Communities..."
- C-106/77, Simmenthal II  ECR 629, duty to set aside provisions of national law which are incompatible with Community law.
- C-106/89 Marleasing  ECR I-7321, National law must be interpreted and applied, insofar as possible, so as to avoid a conflict with a Community rule.
Depending on the constitutional tradition of member states, different solutions have been developed to adapt questions of incompatibility between national law and EU law to one another. Community law is accepted as taking precedence to the law of Member States, but not all Member States share the analysis used by the European institutions about why EU law overrides national law, when a conflict appears.
- Raoul George Nicolo  1 CMLR 173
- Solange II (Re Wuensche Handelsgesellschaft, BVerfG decision of 22 October 1986  3 CMLR 225,265)
- Frontini v. Ministero delle Finanze  2 CMLR 372
- C-213/89 Factortame I  ECR I-2433, Duty on national courts to secure the full effectiveness of Community law, even where it is necessary to create a national remedy where none had previously existed.