We may have gotten lucky that they happened to be reasonable men who wanted to be left alone to do business, with Montesquieu, and by extension, the history of the Roman empire, to fall back on. Much is made of John Locke’s influence but when you study the history of the Roman Empire in detail, particularly the transition from Republic to Empire, there are many good and subtle lessons about separation of powers in that history.

Can you have a Democracy? Yes, but it tends to vote itself into madness without a check.

Can you have a Caesar? Yes, if he’s not too young, too old, or poorly educated, or crazy, or in the pocket of the army, or is free to make shit up as he goes along without consequences.

Can you have a Republic? Yes, but without diversified opinions at the top, and a uniform system of laws that everyone must follow, it’s not much good and will decay into venal satrapy without tending.

My understanding is that we can thank Montesquieu for an essentially anthropological study of ancient politics. Separation of powers, and checks and balances, is very under-rated in the teaching of American Revolution. We’re so hung up on treating those men as White Gods of Goodness that we ignore larger lessons about where they got their ideas from.