Still today, John Stuart Mill's understanding of political liberty constitutes a very important and timely theme for philosophical research. The article lays out Mill's proposal, showing how it goes to the very heart of the political problem: society is a space in which men must live together to attain a happiness that is always personal and individual, albeit conditioned by the fact of living with other men. Hence the political setting is fundamental for personal happiness, and yet such happiness transcends the social. Mill wants to offer a conception of the relations between individual and society that guarantees the freedom needed for each one's attaining happiness without subordinating his freedom to social interests. However, conditioned as it is by the principle of maximum utility, Mill's thesis contains various limitations that cast doubt upon its internal coherence and its practical feasibility. The article presents five considerations as to its consistency and plausibility, with a view to determining whether the conception of political liberty developed by Mill succeeds in resolving the question of the balance between individual independence and social control.