European integration was permanently on Luns's political agenda. Beyen had introduced the concept of the European Economic Community. In March 1957, Luns signed the Treaties of Rome establishing the EEC and Euratom. Although he preferred integration of a wider group of European states he accepted the treaty and defended the supranational structure it was based on. The endeavours of French president Charles de Gaulle to subordinate the institutions of the Six to an intergovernmental political structure, could count on strong opposition from Luns: such plans would, in his view, serve only French ambitions of a Europe independent of the United States.