This paper outlines an empirically-grounded account of normative political legitimacy. The main idea is to give a normative edge to empirical measures of sociological legitimacy through a non-moralised form of ideology critique. A power structure’s responsiveness to the values of those subjected to its authority can be measured empirically and may be explanatory or predictive insofar as it tracks belief in legitimacy, but by itself it lacks normative purchase: it merely describes a preference alignment, and so tells us nothing about (...) whether the ruled have reason to support the rulers. I argue that we can close this gap by filtering the preferences of the ruled through a form of non-moralised epistemic ideology critique, itself grounded in an empirical account of how belief in legitimacy is formed. (shrink)