One of the challenges posed to the general appeal of Kant's legal and political philosophy is its strong legitimizing impulse. The usual criticism imputes to it the legitimization of all regimes, which then generates two big problems. Firstly, there is the unattractive implication of the existence of a duty of obedience even to openly malevolent regimes. Secondly, the accusation points to the incoherency to which the existence of such a duty leads to, rendering the complete edifice of Kant's morality inadequate by the unresolvable conflict between the duty of obedience to the state and some other duties entwined in the system. By invoking Kant's concept of barbarism, I argue that his normative system can accommodate the fact that some claims of political legitimacy should be made null and void, i.e. that there is no duty of obedience to those who claim the status of legitimate state authority without proper justification. Strictly speaking, there can still be no right of rebellion (owing to the way in which Kant's scheme presupposes the existence of legitimate state authority in order for there to be any rights at all), but it is justified to resist regimes that are classified as barbaric. I single out the contemporary authors who point to the possibility of such a classification, found in Kant's Anthropology, I show why it has remained mostly unnoticed, and how the concept of barbarism, if elaborated, can be used in the assessment of political legitimacy. I see barbarism as a use of monopolistic force resulting in there not being a state of right in a certain territory, i.e. in nullifying the essential elements of both private and public right. By elaborating each of them (including free speech), I point to the ones that constitute the bare minimum of legitimacy.