In the aftermath of the EDC's collapse, many ideas were put forward to resume the process of integration. The president of the ECSC High Authority, Frenchman Jean Monnet, favored expanding the ECSC to encompass other sources of energy as well as public transportation, and he suggested creating a new community for the peaceful use of nuclear energy. Other policymakers proposed the establishment of a common market or even an economic union. All of these ideas eventually were included in a memo that the foreign ministers of the Benelux countries (Belgium, the Netherlands, and Luxembourg) circulated among the ECSC members on 18 May 1955. On 1–2 June 1955, in Messina, Italy, the ECSC foreign ministers decided to set up an intergovernmental committee under Belgian Foreign Minister Paul-Henri Spaak to explore the options presented in the Benelux memo.
Spaak's committee met in Brussels during July 1955–April 1956 and focused on the creation of a common market and an atomic community. On 29–30 May 1956, the committee's final report, which had suggested the creation of two new communities, was discussed and approved in Venice by the six ECSC foreign ministers, who decided to use it as the basis for a new round of negotiations. These talks, chaired by Spaak, began in June 1956 but soon ran into a number of difficulties. The West Germans were skeptical about turning their newly created nuclear industry over to a supranational authority, preferring instead to concentrate on the creation of a common market that would benefit their expanding industrial exports. The French, on the other hand, were reluctant to abandon their old protectionist habits and insisted on the creation of an atomic energy community, particularly if this could be endowed with a joint European isotope separation plant for the production of enriched uranium.
The stalemate was broken by the Soviet invasion of Hungary and the disastrous Anglo-French military expedition in the Suez Canal in October 1956. The crises revealed Western Europe's powerlessness and dependence on the United States and acted as a catalyst for the conclusion of the negotiations. The last obstacles were overcome in early 1957, and both treaties were signed in Rome on 25 March 1957. All countries ratified the treaties before the end of the year, and on 1 January 1958 the two new communities were formally established. While EURATOM never acquired the important role that Monnet and others had envisioned for it, the EEC contributed to the continuous economic growth of Western Europe and quickly became the central pillar of European integration.
President Dwight D. Eisenhower's administration showed much support for the negotiations but expressed its favor mostly in private talks, as it feared a repetition of the EDC debacle when the public display of American enthusiasm for the project backfired, making the EDC appear an American rather than a European design. Great Britain, on the other hand, displayed only a limited interest in the early phase of the negotiations, and as they picked up speed, Britain declined to participate any further. Subsequent attempts to merge the EEC into a larger free trade area, including Britain, failed. Thus, the Treaty of Rome deepened what hitherto had been only a limited chasm between Great Britain and continental Western Europe, potentially introducing a source of friction between London and the six EURATOM/EEC members.
Moravcsik, Andrew. The Choice for Europe: Social Purpose and State Power from Messina to Maastricht. Ithaca, NY: Cornell University Press, 1998.