The International Labour Organization (ILO) played a concrete role in shaping the mechanisms of international economic co-operation created in Western Europe in the early post-war years. Its tripartite composition and orientation towards social dialogue were perfectly in tune with the productivist principles sponsored by the United States after the Second World War, which largely permeated European economic integration. Thanks to its solid know-how in the field, the ILO made a key contribution in promoting labour mobility, by helping the organisation and co-ordination of national employment services and vocational training systems and, most of all, by assisting institutions such as the Organisation for European Economic Co-operation (OEEC) and the European Communities in implementing freedom of circulation between their member countries. At the same time, in the mid-1950s it offered theoretical support to the economic liberalism on which the European common market was being modelled, arguing against claims for social harmonisation as a precondition to economic integration, and thus contributing to giving European co-operation the shape which still characterises it today.