Abstract
Since 1973 the Portuguese Socialist Party (PS) has undergone major ideological and structural changes. The original ideological framework was conditioned by the widespread dominance of ‘Mediterranean socialism’, which differed from the social democracy of the northern European countries in to its emphasis on Marxist ideology. The ideological transformation took place during and after the revolutionary process, in the later phase of which the challenge from the Communist Party within the left became less important. The social democratisation of the Portuguese Socialist Party was complete in 1986, when modernisers began to gain top positions inside the party. Between 1986 and 1995 the modernisation of the party led not only to a convergence of the PS with northern social democracy but also allowed for a more flexible approach towards the electoral market. In spite of the successes in the 1995 and 1999 legislative elections, the resignation of prime minister Antonio Guterres in December 2001 showed the limits of the implementation of the party's modernisation programme within the context of Europeanisation.