During the Progressive Era (1880-1920), leading thinkers and politicians transformed American politics. Historians and political scientists have given a great deal of attention to the progressives who effected this transformation. Yet relatively little is known about the conservatives who opposed these progressive innovations, despite the fact that they played a major role in the debates and outcomes of this period of American history. These early conservatives represent a now-forgotten source of inspiration for modern American conservatism. This volume gives these constitutional conservatives their first full explanation and demonstrates their ongoing relevance to contemporary American conservatism.