Political liberalism purports to be independent from any controversial philosophical presuppositions, and its basic principles and features are often presented as the most accommodating of difference and heterogeneity, so long as the latter is not illiberal, oppressive and fanatic. Educational theory welcomes this assumption and attempts to utilise it in citizenship curriculum debates, often in a receptive and arguably uncritical way. I shall critique the above by unveiling the contestable epistemological and anthropological theses underlying Rawls' difference principle and by discussing the conception of education that they ground. I shall draw especially on sociology of education and its questioning of the "racism of intelligence" in order to show that political liberalism mistakes its self- and world-understanding as a reflection of general and undisputed facts. Further, I shall explain how a more critical perspective would give educational theory a more active role by challenging the so-called "reproductive" conception of education. I shall conclude by assessing the significance of such a critique for teaching citizenship, putting forward some suggestions for a reorientation of political education.