In his review of my book, Samuel DeCanio immediately picks up on the largest struggle that I faced in conducting this research: measurement. In writing the book, I was interested in bringing quantitative tools to bear on American political development questions. This led me to historical census data, as well as mapping data that I developed on my own. However, there are at times a distinct gap between what these variables measure and what I am actually interested in. I was caught between data that I felt were valid and what the data were actually capable of telling me. However, I still think that the data I selected were the right choice. Similarly, I believe that focusing on Washington, DC—as the site of American political power—is also the correct, though imperfect, choice in doing my international comparisons. My goal in all of my analyses was to look at larger trends in railroad development and how it unfolded across the decades before the Civil War. I hoped to capture not just how one state or one rail company developed but, rather, how the entire national process of railroad development unfolded. In order to do this, I relied on quantitative as well as qualitative tools. While the historical data available to me were not always ideal, I still believe that they reveal a great deal of new information about how railroads developed in conjunction with federalism in the years before the Civil War.

In addition, DeCanio raises two important theoretical points that deserve attention. First, he points out that the closing of my book argues that federal rail action served to build federal power generally. I make this claim based on land grants to states that provided the federal government with the power to move troops and mail cheaply along the routes constructed by those grants. DeCanio is correct in asserting that these data do not fully show that control over shaping space necessarily led to more federal power. However, I would contend that control of both troops and mail are critical federal powers, and railroads were key to shifting that federal might more fully into the nation’s interior. Nonetheless, DeCanio’s point does still stand: The ways in which spatial rationalization turns into direct political power do deserve more attention. Railroads are obviously critical to this story, and I simply lacked the space in this text to fully grapple with that issue. But in the future, this is exactly the issue to which I would most like to return.

Finally, I was intrigued by DeCanio’s interest in presidents’ failures to act on the railroad issue. Previously, I had not considered the importance of thinking about institutional failure. My current work is actually interested, broadly, in the related question of institutional decline. Hence, I find it interesting that DeCanio identifies that thread appearing in my book as well. Ultimately, he has raised a number of important issues, regarding both the difficulty of working with imperfect data and the theoretical reach of any single book-length study. Within these limits, however, I believe that the central arguments of Railroads and American Political Development hold up to the sort of careful scrutiny that he has given to them.