Conclusion
Interpreting the US Constitution as an instrument of federal union has important implications in terms of understanding of the American founding. The Constitution mattered much more to the international than to the domestic history of the United States. Its importance to the latter was dwarfed by the role of state constitutions and state legislation. The Constitution provided the institutional basis on which the nation would grow in territory, population, and riches in the nineteenth century. But if the federal government was active in foreign policy, so-called Indian diplomacy, and the management of the national domain, it played only a limited role in domestic developments. To understand the processes of economic and political modernization that characterized the United States in the nineteenth century, that is, the transition to a market economy and to liberal democracy, it is necessary to study the actions and inactions of the American state governments.