Pettit endorses a ‘republican’ conception of social freedom of the person as consisting of a state of non-domination, and takes this to refute Mill’s ‘liberal’ claim that non-domineering but coercive interference can compromise social freedom of choice. This paper argues that Pettit’s interpretation is true to the extent that Mill believes that the legitimate, non-arbitrary and just coercion of would-be dominators, for the sake of preventing them from dominating others, can render them unfree to choose to do so without rendering them socially unfree (qua dominated) persons in their own right. However, contra Pettit, Mill is correct to reject the ‘republican’ view for at least two reasons. Firstly, it enables him to avoid commitment to the implausible implication that would-be dominators who sincerely deny any interest in a shared system of basic liberties are automatically rendered unfree persons by the coercion necessary to uphold such a system. Secondly, it enables him to avoid begging the question against ‘immoralists’ like Nietzsche, whose opposition to systems of reciprocal non-domination is at least partly motivated by the losses of social freedom of choice they entail for those they deem to be worthy of dominating others.