Internationale Handelsgesellschaft and Simmenthal cases

- Court of Justice (Photo: EU Commission)
Important EU law cases from 1970 and 1977 in which the EU Court laid down that EU law should over-rule national constitutions. Since then the principle that national laws must be amended to be in accordance with EU law, and not vice versa (i.e. the principle of the primacy of EU law) also covers national constitutions. Case 11/70 and 106/77.
Within the member states, the supremacy of EU law over national constitutions is only explicitly recognised in the Constitution of the Republic of Ireland
Future
As something completely new, the rejected EU Constitution contained an explicit demand that the supremacy of EU law be respected. It also repeated the member states' duty of unconditional loyality, as well as a prohibition on conflicts between the EU and its member states being resolved anywhere other than at the EU Court. See Art. 6 in the rejected EU Constitution.
In the proposed EU Constitution the primacy of EU law was established in plain speak in Art. I-6. This article is now turned into a Declaration 17 on primacy. It is just as precise but more difficult to read. The Opinion of the Council Legal Service, also annexed to the Final Act, considers the principle of primacy as the cornerstone principle of Community law by referring to the famous Costa/Enel sentence: "It follows (…) 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."
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See also Costa/Enel and Karlsruhe.

