Political realists claim that politics should be regulated by a distinctive political normativity, one that does not rely on external, pre-political moral standards. It is in this sense that they distinguish political realism from ‘political moralism’, regarded as an approach that understands political theory as applied ethics. Importantly, realists’ anti-moralism is not motivated by the conviction that moral considerations do not play any role in the political realm. Rather, the target is the externalism of the normative resources on which moralist theories typically ground their conceptions of legitimacy. In contrast to moralists, some realists have argued for the need to elaborate internal theories of legitimacy, ones that develop normativity internally – that is, from within the political context under evaluation. This commitment entails the effort to reconnect legitimacy to the beliefs and attitudes of people subjected to the political power. In these accounts of legitimacy, critique is typically exercised internally, by means of self-reflection and ideology critique. Contra some realists, I argue that some forms of externalism are desirable and compatible with internalist accounts of legitimacy, and I show how to accommodate them within internalist theories of legitimacy. They are desirable because they strengthen the emancipatory potential of internal reflection and, in some cases, even stimulate it, as when, because of political circumstances, internal critique cannot be exercised. In addition, they prevent internalist approaches from falling into descriptive accounts of de facto acceptance of power. These forms of external critique can be compatible with internalist accounts of legitimacy, provided that they do not contrast with what I call methodological and substantive internalism. Accordingly, in the article, I discuss which stances of external critique can and should be accommodated within internalist accounts of legitimacy, without renouncing to the realist character of the approach.