This chapter attempts to reframe the way in which the liberal tradition is understood. It opens with a critique of some existing interpretive protocols used to delimit political traditions. It then introduces a new way of conceptualizing liberalism, suggesting that it can be seen as the sum of the arguments that have been classified as liberal, and recognized as such by other self-proclaimed liberals, across time and space. The second half of the chapter analyzes the emergence and subsequent transformation of the category of liberalism in Anglo-American political thought between 1850 and 1950. It traces the evolution of the language of liberalism in nineteenth-century Britain, and explores how the scope of the liberal tradition was massively expanded during the middle decades of the century, chiefly in the United States, such that it came to be seen by many as the constitutive ideology of the West. It argues that this broad understanding of liberalism was produced by a conjunction of the ideological wars fought against “totalitarianism” and assorted developments in the social sciences.