In the late nineteenth and early twentieth centuries, in response to profound changes in the nature of the nation's political economy and an array of social and political forces influencing and arising out of them, a New American State was built. Although it never achieved the unity and solidity of the benchmark continental European states, its centralized, bureaucratic, and administrative features nonetheless marked a radical departure from the constitutional system of governance – the state of courts and parties – that preceded it. This preexisting state of courts and parties was structured by the provisions of the original Constitutional text (as amended) as understood in light of traditional and relatively stable (if not always purely original) constitutional principles as set out in the nation's founding texts and in writings about those texts, such as The Federalist Papers, key Supreme Court opinions, and the learned and authoritative glosses of the great nineteenth-century treatise writers, such as Kent, Story, and Cooley. The building of the New American State – with its radically centralizing tendencies, its transformative, radically statist commitment to a government of general, rather than enumerated, powers, and its affinity for the promise of administration – severed the relationship between the prevailing institutions of state and the sources of its legitimacy in traditional American constitutionalism.

The severing of state from Constitution at this time provided the impetus for the creation of modern constitutional theory.