The twentieth-century American state was not a product of autogenesis, emerging spontaneously from a peculiar conjunction of economic and social forces. Certain individuals were responsible for constructing the new governing institutions and crafting the legal framework within which they were to operate; certain other individuals worked to obstruct that process and preserve older modes of decision making inherited from the “state of court and parties” that preceded it. Many of the formative acts of creation were carried out in Congress. It is important to identify who was responsible for the reform legislation that constituted the blueprint for the new American state and to investigate, so far as we can, the constituencies that they represented, the social pressures that they were subjected to, and the reasons that they gave for supporting reform. In short, who were the progressives, and who and what did they stand for? Such an exercise will help us to locate the process of state building within the field of partisan conflict and to relate movements for progressive reform to the distribution of opinion within the Republican and Democratic parties.

The political parties in Congress retained a pronounced tendency to stick together even when confronted by the new, and supposedly divisive, issues of progressive reform, which makes the analysis of congressional voting particularly difficult. Examination of both parties together does little more than register their tendency to oppose one another. Therefore they are best considered separately.