The following article aims to determine under which circumstances the establishment of denominational schools must be allowed in democratic societies. The possible opening of a Muslim Brotherhood School in Spain requires a new approach on the presence of religious schools through the study of the collision between two protected goods raise: freedom of religion and democratic citizenship. Thus, it is first considered which space democratic States must grant to religious institu-tions, turning to Cecile Laborde's considerations on French laicism from a liberal Span-ish perspective. Subsequently, the article proceeds to reconcile freedom of religion and democratic citizenship education, choosing the political liberal approach over the com-prehensive liberal approach, since it provides solutions that are easier to assume by the standard reasonable citizen. Once the theoretical framework has been established, the tension between these two goods is analyzed through the triangle of actors of Arneson and Saphiro, in order to determine under what circumstances the existence of denomina-tional schools must be tolerated. Said triangle shows the tension between the State, who seeks to educate good citizens (democratic citizenship education), the parents, who seek that their children share their same conception of the good life (freedom of religion) and, in between, the children, whose best interest must come first. On the one hand, the results do not only show that religious institutions are compatible with democratic States, but also that said States must guarantee, in pluralistic societies, the different conceptions of the good life. On the other hand, regarding the conciliation between freedom of religion and democratic citizenship, the article showcases that, in order for the best interest of the child to be guaranteed, neither the State nor the parents can prevail, rather both interests must balance in the following way: the State must allow the existence of confessional schools as long as they teach the core contents of democratic citizenship education. Finally, the article argues that democratic citizenship education in confessional schools is not inferior to that of public schools, and criticizes the positions according to which citi-zens must put aside the religious aspect in democratic societies. The article pretends to discuss the traditional liberal theoretical framework, from which it has reflected the reli-gious education, compelling a re-reading of the triangle of actors.
