John C. Calhoun (1782-1850) was one of the most important figures of American politics in the first half of the 19th century. He has been studied at length in particular as a politician and only partially as a political thinker. In this book the author demonstrates the greatness of Calhoun's thinking. He elaborated the theory of the «tyranny of the majority», of élites, of the modern political party, of politics as a profession, and the «steel cage» - to use Weber's expression - constituted by the wielding in a single hand of political power and economic power. All these themes have as their central element the relationship between power and freedom in the modern world in an anti-centralist and federalist conception of institutions. Salvadori reaches the conclusion that Calhoun must be considered one of the most important political thinkers of the last century. However he was also an «embarassing genius» for much of American culture, because of his antinationalist views.