In one sense, the debate over the Constitution of 1787 amounted to a battle to determine the true heirs to the new science of politics as expounded by Montesquieu. Scholars frequently note the relationship of Montesquieu to the American framers, usually emphasizing such topics as small republics or the separation of powers. This dissertation takes a different approach by comparing the ways that they considered the relationship between institutional design, the character of a people, and social, cultural, and other factors, to be relevant to institutional design and statesmanship.Chapters 2-5 then explicate how Montesquieu indicates that the concept of spirit informs political practice, both generally and particularly in the cases of the English model, monarchies, and republics. The Federalist, Publius takes account of the circumstances and the character of the American people. Publius also, in effect, adapts Montesquieu's English, monarchic, and republican models in order to render them fit for the American people. In contrast, the Anti-Federalists part ways with the Federalists, in part, because of their own emphases and applications of Montesquieuan themes. First, the Anti-Federalists stress the limits of politics and the dangerous uncertainties of innovation. Second, they desire to conserve both the American spirit and diversity among the states. Finally, they exhibit an awareness of the social dynamics of the separation of powers.