The chapter offers a comparative study of the politics of the French Parti Socialiste (PS), the Italian Partito Socialista Italiano (PSI), the Spanish Partido Socialista Obrero Español (PSOE), the Greek Panellinio Sosialistiko Kinima (PASOK), and the Portuguese Partito Socialista (PS). The chapter will compare their social and economic policies: it will examine similarities and differences and compare them with the politics and policies of other socialist parties. From 1945 onward, many social democratic parties experienced changes in their policies. Gaitskellism in the United Kingdom, the Bad Godesberg congress in Germany, the changing program of the Swedish Sveriges Socialdemokratiska Arbetareparti (SAP) had replaced as the core of their policies the nationalization of private firms by redistributive policies guided by egalitarian principles. Increases in public expenditure in health, education, pensions, and general welfare were their new political identity. During the period examined in this chapter, public spending shrank in seven of the twelve European Community economies but rose in France, Denmark, Spain, Italy, and Greece. Social democracy, everywhere, was increasingly conceived as a combination of socialism and liberalism. At the core was an idea of equality that had its roots in Eduard Bernstein, Anthony Crosland, Olof Palme, Julián Besteiro, Indalecio Prieto, or Stephen Lukes. An important “rational” contribution to a conception of equality that is at the core of social democracy is John Rawls analysis of the welfare decisions of rational individuals who are ignorant of their future and want to minimize risks, as well as the conception of “citizenship” developed by Thomas H. Marshall. “Citizenship” came to be associated by a combination of “rights” that could be satisfied by “mobility policies” (equality of opportunities) and “consumption policies” (equality of condition). The chapter examines the evolution of the Gini coefficients in different European countries, with governments of different ideological identity. The chapter then turns to examine, in comparative terms, the Southern European experience of social democracy. It examines France, Italy, Spain, Portugal, and Greece. In the Southern European populations, “political cynicism” was considerable and, simultaneously, demands for redistribution and “social egalitarianism” were very extended. Southern European societies varied in the strength of anti-socialist, conservative forces. In Italy and Greece, these were more unified; in France and Spain, more fragmented. There were also differences in the strength of the Communist parties: weaker in Greece and Spain. Social democratic politics were guided by two objectives in Southern Europe: the consolidation of democratic institutions and the reinforcement of a weak welfare state in order to develop policies of greater equality of opportunities and of reduction of inequalities of condition. The chapter compares the evolution of social democratic policies of the French PS, the Spanish PSOE, the Italian PSI, the Portuguese PSP, and the Greek PASOKand the resistance they encountered from conservative forces. It assesses their record on growth, inflation and unemployment. And also their record in promoting policies of promoting a greater equality of opportunities and a reduction of socioeconomic differences. And the chapter also studies the resistances to social democratic parties: not just by political forces, but by extraparliamentary forces, for instance, by a judiciary who occasionally confronted not just social democracy, but democracy. The Spanish experience is particularly illustrative, as a very large part of the judiciary had not been renovated in the passage from dictatorship to democracy.