The distinction between negative and positive liberty is familiar to political philosophers. The negative variety is freedom as noninterference. The positive variety is freedom as self-mastery. However, recently there has been an attempt on the part of a growing number of philosophers, historians, and legal scholars to recapture a third concept of political liberty uncovered from within the rich tradition of civic republicanism. Republican political liberty is freedom as nondomination. I argue that features that distinguish it from noninterference and self-mastery highlight the theoretical and practical advantages of liberty as nondomination. It is, among these candidates, best-suited to serve as the guiding principle for the State’s basic institutions and rules. The principle says that the State should secure nondomination among its citizens.