To explore the transatlantic emigration of the ‘comparative method’(s) is to recover the range of European work – in institutional history, comparative legislation, and the theory of the State – that scholars in the nascent American science of politics drew on in the late nineteenth century. Their nascent science was, however, not merely derivative, and in the changing practices of comparative study from the mid-1880s through 1900 a distinctive American ‘political science’ began to emerge.