This article highlights the elements of both continuity and discontinuity in the international action of the Italian Socialist Party during the decade 1956-1966, stressing the close connection between the change of its international reference points and the evolution of its strategy within the domestic context. In the first part, the A. illustrates the features of the debate that shook the Party when the socialists came to shape their own international outlook in terms of neutralism, focusing in particular on the ideological controversy that set the "left" wing against the "autonomist" wing led by Nenni and Lombardi on such crucial matters as Europeanism, support to the Non-Aligned Movement, rapprochement to European Socialism and, in the final analysis, on the lines of foreign policy judged compatible with the participation in the centre-left government. In the second part, the A. examines, firstly, the role of foreign policy in determining the power balance within the centre-left coalition. Finally, the A. reconsiders the discussions on Europe and the revolutions in the Third World which animated the Party up until its re-unification with the Social Democratic Party and its confluence into the family of European Socialism.
Keywords: Italian Socialist Party, Pietro Nenni, Riccardo Lombardi, Non-Aligned Movement, European socialism, neutralism