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 or internal controls on government would be necessary. In forming a government which is to be administered by men over men, the great difficulty lies in this: you must first enable government to control the governed; and in the next place oblige it to control itself.
James Madison, The Federalist No. 51.