Este artículo es un comentario y análisis de algunos aspectos relacionados con el contenido del Documento “Constitución, Laicidad y Educación para la Ciudadanía”, del PSOE (diciembre de 2006). El autor analiza los modelos constitucionales de 1931 y 1978 en relación con la libertad religiosa, expone las condiciones y modos del diálogo público entre creyentes y no creyentes en una sociedad democrática, así como el entendimiento de la muticulturalidad presente en el documento. Explica igualmente las variantes del fundamentalismo y los problemas generados por la asignatura Educación para la Ciudadanía. ABSTRACT: This article is a commentary and analysis on the content of the document-manifesto “Constitution, Separationism and Education for Citizenship” of the Spanish Socialist Party (PSOE) of December, 2006. The author explains briefly the distinction between the model of relations between Church and State in the Spanish Constitutions of 1931 and of 1978. The document-manifesto assumes a particular vision of the Constitutional premises and ideological framework under which the term “separationism” has a specific meaning which goes far beyond the “co-operation” and “separation” principles enshrined in the Constitution of 1978. The author of the article addresses the terms and conditions under which the dialogue between believers and non-believers could be developed in a modern democratic society and the basic content of multiculturalism management that the document-manifesto embraces. Looking carefully towards the general content of all forms of fundamentalism, the author analyzes secular fundamentalism. Finally, the author explains very briefly the need of the subject Education for Citizenship in Spanish Schools and the social upheaval which has arisen in Spain concerning this subject.