Unified Socialist Party
Partito Socialista Unificato
LeadersPietro Nenni
Giuseppe Saragat
SecretariesFrancesco De Martino
Mario Tanassi
PresidentPietro Nenni
IdeologyDemocratic socialism
Social democracy
Political positionCentre-left
International affiliationSocialist International

The Unified Socialist Party (Italian: Partito Socialista Unificato), officially called Unified PSI–PSDI (PSI–PSDI Unificati), was the name of the federation of parties formed by the Italian Socialist Party (PSI) and the Italian Democratic Socialist Party (PSDI) from 1966 to 1969.[1][2] The parties membership was composed of 700,964 activists in 1966.[3]


The two parties joined forces in 1966, after the PSI had joined the Italian government in 1963 for the first time since 1947, as part of Aldo Moro's cabinets, composed of Christian Democracy, the Italian Republican Party and the PSDI.

The united party achieved just 14.5% of the vote in the 1968 general election,[4] due to the competition of the PSI's dissidents of the Italian Socialist Party of Proletarian Unity, the PSI-PSDI returned officially to the name PSI in October 1968, causing the split of the PSDI's former members in July 1969: these formed the "United Socialist Party", which was finally renamed PSDI in 1971.[2]


Party Main ideology Leader/s
Italian Socialist Party Democratic socialism Pietro Nenni
Italian Democratic Socialist Party Social democracy Giuseppe Saragat

Electoral results

Italian Parliament

Chamber of Deputies
Election year Votes % Seats +/– Leader
1968 4,603,192 (3rd) 14.48
91 / 630
Senate of the Republic
Election year Votes % Seats +/– Leader
1968 4,354,906 (3rd) 15.22
46 / 315


  1. ^ Mark F. Gilbert; K. Robert Nilsson; Robert K. Nilsson (1 April 2010). The A to Z of Modern Italy. Rowman & Littlefield. p. 333. ISBN 978-0-8108-7210-3.
  2. ^ a b André Krouwel (20 November 2012). Party Transformations in European Democracies. SUNY Press. p. 327. ISBN 978-1-4384-4483-3.
  3. ^ "Archived copy". Archived from the original on 2013-11-10. Retrieved 2013-11-10.((cite web)): CS1 maint: archived copy as title (link)
  4. ^ Ram Mudambi; Pietro Navarra; Giuseppe Sobbrio (1 January 2001). Rules, Choice and Strategy: The Political Economy of Italian Electoral Reform. Edward Elgar Publishing. p. 39. ISBN 978-1-78195-082-1.