When, in The Social Contract, Rousseau confronted the possibility that the people, while willing the good, might not always be able to see the good, he reached back to ancient Greek and Roman traditions and suggested the Legislator, the extraordinary individual with sufficient wisdom to establish a system of laws and institutions that would enable a society to manage its affairs in peace and justice.
Our Founding Fathers were not much influenced by Rousseau, but they were faced with the same difficulty, not as a matter of theory but of practical experience: the people did not always see clearly, so republican governments sometimes did unjust things. Moreover, the existing institutional structure seemed to be failing in ways that brought republicanism itself into doubt. Could men, ordinary men, really govern themselves?
So the Convention of 1787 was thrust into the role of Rousseau's Legislator, like Solon creating the best government that the people would accept.
At the outset I confess an ambivalent attitude toward its work. It did, and failed to do, good things and bad things. The bicentennial has seen the publication of much good research and interpretation, but quite insufficient critique. The Convention was not a gathering of demigods, but it was a meeting of some powerful minds, experienced politicians who felt themselves at least partially emancipated from the influence of public opinion. They made the second American revolution, thereby obviating some perceived difficulties residual from the original Revolution. They also, however, created a structure capable of dangerous and uncontrollable concentration of power.