One of the most frequently overstated concepts in American constitutional theory is the “separation” of powers. The Framers of the Constitution began with the proposition that concentration of power was to be avoided. They understood, on the other hand, that if governmental powers and responsibilities were actually set apart, each branch would exercise its powers in isolation from the other coordinate branches, to the detriment of cooperation and accommodation among them. Governance would be at best inefficient and at worst impossible. The structure the Framers did in fact create was thus a system of separated institutions sharing overlapping powers. The interaction among these institutions was seen as critical to the practical working of government through competition, accommodation and compromise. “This separation is not merely a matter of convenience or of governmental mechanism. Its object is basic and vital, namely, to preclude a commingling of these essentially different powers of government in the same hands.” On this point, the Framers were profoundly influenced by Montesquieu, who inveighed against the concentration of power in any single branch of government.
