The separation of powers, the concept that the legislative, judicial, and executive branches of government ought to be separate and distinct, is a central feature of the United States Constitution. Through this separation, each branch works according to its own authority, forming a check or balance against any abuse of power by the remaining two branches.1 James Madison, the Founding Father most often credited with including this feature in the constitution, declares, “no political truth is certainly of greater intrinsic value” (Federalist Papers No. 47).

Most consider the French philosopher Charles Louis de Secondat Baron de Montesquieu the author of this system of checks and balances.2 The Founding Fathers repeatedly cite his work Spirit of the Laws as the authority on the issue.3 Madison himself proclaims, “the oracle who is always consulted and cited on this subject is the celebrated Montesquieu” (ibid.). Nevertheless, this paper proposes that--while Montesquieu may have presented the framers of the Constitution with the most modern incarnation of that principle--he borrows too heavily from Polybius and the ancient theory of the mixed constitution (mikth/) to be credited accurately as its originator.

The arguments for this position will be presented in three chapters. The first will trace the origins of the theory of mixed constitution to antiquity and especially Polybius’ Histories,4 while underscoring similarities between Polybius’ system and that of the American Constitution. Other sources will include Herodotus, Thucydides, Plato, Aristotle, his pupil Dicaearchus of Messana, Diogenes Laertius, and Cicero.

The second chapter will explore the availability of the Histories to the Founding Fathers, addressing whether they were aware of Polybius’ teachings on the separation of powers. In particular, a survey of the works of Jefferson, Madison, Monroe, Otis, Adams, and Hamilton will serve as representative of what was available to the framers of the constitution generally. Note that while Jefferson was not present at the convention himself (he was representing the United States in Paris at the time), he was in correspondence with many who did attend and had presented them with books, material, and ideas from Europe.

The third chapter will focus on Montesquieu himself, exploring the extent to which his own work is based on that of Polybius and the classical tradition of the mixed constitution. Particular attention will be given to the fact that several of his recent predecessors had already touted the efficacy of separation of powers long before the publication of Montesquieu’s works. Key sources for this chapter will include Harrington, King Charles I of England, Locke, Bolingbroke, and Blackstone, as well as the criticism of several modern scholars who call into question the indispensability of Montesquieu in America’s adopting the separation of powers.