Kevin DeYoung, at DeYoung, Restless, & Reformed, remarks here that a true understanding of man's fallen human condition animates Federalist 51, and Donald Applestein at the Constitution Daily tells Why James Madison Thought Ambition was a Good Thing (hint: it has something to do with checks and balances).
As individuals, we continually deceive ourselves that "I know best" and that my superior intellect, cleaner motives, purer desires, and truer religion justifies just about anything in getting my way. When fallen individuals gain prominence and power-- or become governors-- this deception is truly threatening. "Checks and balances" was genius.
Celebrate Federalst 51 today! An excerpt:
But what is government itself, but the greatest of all reflections on human nature? If men were angels, no government would be necessary. If angels were to govern men, neither external nor internal controls on government would be necessary. In framing a government which is to be administered by men over men, the great difficulty lies in this: you must first enable the government to control the governed; and in the next place oblige it to control itself. A dependence on the people is, no doubt, the primary control on the government; but experience has taught mankind the necessity of auxiliary precautions. This policy of supplying, by opposite and rival interests, the defect of better motives, might be traced through the whole system of human affairs, private as well as public. We see it particularly displayed in all the subordinate distributions of power, where the constant aim is to divide and arrange the several offices in such a manner as that each may be a check on the other that the private interest of every individual may be a sentinel over the public rights. These inventions of prudence cannot be less requisite in the distribution of the supreme powers of the State. But it is not possible to give to each department an equal power of self-defense. In republican government, the legislative authority necessarily predominates. The remedy for this inconveniency is to divide the legislature into different branches; and to render them, by different modes of election and different principles of action, as little connected with each other as the nature of their common functions and their common dependence on the society will admit.