Shapiro discusses the different answers that have been proposed by the major political theorists in the utilitarian, Marxist, and social contract traditions over the past four centuries. Showing how these political philosophies have all been decisively shaped by the core values of the Enlightenment, he demonstrates that each one contains useful insights that survive their failures as comprehensive doctrines and that should inform our thinking about political legitimacy. Shapiro then turns to the democratic tradition. Exploring the main arguments for and against democracy from Plato’s time until our own, he argues that democracy offers the best resources for realizing the Enlightenment’s promise and managing its internal tensions. As such, democracy supplies the most attractive available basis for political legitimacy.