The history of federal theory takes a radical turn with the American invention of a new type of federal system in late eighteenth century With the transition from the Articles of Confederation of 1781 to the Constitution of 1787, the United States became the first example of what we now refer to as a federation, as distinguished from a confederation. For the first time in both practice and theory, the new Constitution proposed a union not just of political entities, like states, but also of all of the citizens of all of these entities. The new central or federal government would represent two kinds of members, states (in the Senate at that time), and individual citizens of the federation itself (in the House of Representatives and the presidency). We now refer to this model of governance as a “federation,” and distinguish it from a “confederation,” which is a union primarily of independent states (and not really of all of the citizens of all of these states). While this terminological distinction would not appear until the late nineteenth century—50 years later Tocqueville was using the terms “new and ancient species of confederation” to mark the difference between what we now call “federation” and “confederation”— the innovative features of the new American system did not take long to generate a major debate. In this third section, we have included selections from five central figures of this new debate: “Publius” (the pseudonym of the three authors of The Federalist, namely, James Madison, John Jay, and Alexander Hamilton); John Calhoun, an antebellum Southern political figure and scholar; Alexis de Tocqueville, an aristocratic observer of the young American republic a half-century after its founding; John Stuart Mill, the great English political philosopher of the Victorian era; and Pierre-Joseph Proudhon, the late-nineteenth-century French utopian-socialist theorist.