John Gray's hostile reading of J.S. Mill's utilitarian doctrine of individual liberty and social authority is rejected in favour of a more sympathetic reading. According to the latter, Mill's doctrine says that every civilized society ought to distribute equal rights to complete liberty of self-regarding conduct. Although clarification of the relevant terms is required, utilitarian calculations are not needed to understand or apply this principle of self-regarding liberty because it is already a utilitarian principle. Mill's doctrine also says that every civilized society has legitimate authority to consider establishing rules of social (or other-regarding) conduct, although society may rightfully decide to adopt broad laissez-faire policies for some types of social conduct, including trade and expression. In particular, to promote the general welfare, any civil society should enact and enforce a legal code of equal justice which distributes equal rights and correlative obligations designed to protect the right-holder from suffering serious harms without his consent. Although its content may vary across different social contexts, an optimal code must always distribute certain basic human rights, including the right to complete self-regarding liberty. Gray's objection that such a moral and political project is defeated by value-pluralism is not persuasive. Under plausible conditions, any people seeking to promote the interests of all must consent by (at least) majority vote to some form of representative government with authority to enact and enforce such a code of justice. Value-pluralism itself, unless it endorses this project at least to the extent of protecting some minimum set of basic human rights, fails as moral and political theory.