in: Oxford Research Encyclopedia of Politics
The Merger Treaty was the first reform of the founding treaties of the European Communities. It was signed by the Member States of the Communities in 1965 and entered into force in 1967. It created a single "executive" by merging the High Authority of the European Coal and Steel Community (ECSC), the Commission of the European Economic Community (EEC), and the Commission of the European Atomic Energy Community (EURATOM). It also formally merged the Councils (of ministers) into one. It did not merge the founding Paris and Rome Treaties, nor the three Communities as such. It was thus a relatively limited reform. The main argument used in support of the merger was one of efficiency and better coordination. The three Communities had overlapping competences, for instance in the fields of energy, transport, competition, and social policy, so it was felt that better coordination was needed. Politically the main difficulty was convincing President Charles de Gaulle of France to support the merger, advocated by the "executives" themselves, the Parliamentary Assembly, and the five Member States other than France.