Costa vs Enel
Case number 6/64: one of the most significant rulings of the Court of Justice, asserting the primacy of EU law over national law in relation to matters covered by the Treaties.
The principle is inserted in the Lisbon Treaty by means of a footnote in Declaration No 17 quoting the Costa-Enel verdict.
Judgement of the Court of 15 July 1964. Flaminio Costa v E.N.E.L. http://eur-lex.europa.eu/LexUr......do?uri=CELEX:61964J0006:EN:NOT