This Article attempts a reconceptualization of developments in Commerce Clause jurisprudence between the Civil War and World War II by identifying ways in which that jurisprudence was structurally related to and accordingly deeply influenced by the categories of substantive due process and dormant Commerce Clause doctrine. Antecedent dormant Commerce Clause jurisprudence set the terms within which Commerce Clause doctrine was worked out; coordinate developments in substantive due process doctrine set limits upon the scope of Commerce Clause formulations and thus played a critical and underappreciated role in maintaining the federal equilibrium. The subsequent erosion of those due process limitations vastly expanded federal power and prompted a crisis in Commerce Clause jurisprudence that was ultimately resolved by adoption of a political process approach to both affirmative and dormant Commerce Clause adjudication. The categories that had unified affirmative and dormant Commerce Clause jurisprudence were abandoned, decoupling the two lines of doctrine and rendering them no longer developmentally interdependent. The two lines went their separate ways, economic substantive due process disappeared, and the enterprise of interdoctrinal coordination that had held a vast body of constitutional law together was lost to history. We continue to study the development of these lines of doctrine in our Constitutional Law curricula, but we do so in an ahistorical manner that obscures understanding. We study the development of doctrine topically rather than synchronically, wresting lines of doctrine from the related doctrinal contexts in which they developed. Such decontextualization, in this case as in others, is a surefire method of making the entire undertaking look preposterous. Looking back at this jurisprudence from the vantage and through the categories of our contemporary constitutional sensibility, it becomes difficult to understand how any intelligent person could ever have taken the enterprise seriously. Yet a very great many clearly did. This piece seeks to understand why and how that could have been, while at the same time explaining why the enterprise unraveled in the way it did when it did. What emerges, I hope, is a new way of thinking and teaching about constitutional development in this critical period
