The term “law” has always had to do double duty. On the one hand, laws are made through a political process. On the other hand, laws are discovered as a system already operating in the world. The legislative output of Congress is the first sort of law; the laws of thermodynamics are the second. When we focus on the social, however, the line becomes blurred. The social order is the site of our legislative projects, yet the very point of social science is to discover systemic laws operating within the community independently of anyone’s project of law creation.1 My ambition in this book, in simplest terms, is to explore this ambiguity in law as it shows itself in American political and legal thought over the long nineteenth century, the period from the American founding to the Lochner Court of the early twentieth century. Over the course of that century, there is a general shift from thinking of law—particularly constitutional law—as the product of a project to thinking of law as an immanent system.