There is a saying, attributed to several sources including David Hackett Fischer, that “Puritans were a people who were never disillusioned.” That being because they held no illusions about the innate depravity of Man and the ability of people to get into mischief (of all sorts), in large part because of their acceptance of the doctrine of Original Sin. In one of his essays about the Constitution, Bernard Bailyn talks about the mindset of the men who wrote the document, and how they knew that people were frail and fallible and would find ways to abuse and misuse anything they could, and how they also knew that men could rise above those same weaknesses. And so the founders created a document to allow for the worst and harness the best. Which is a mindset that again, even though many of the Founders were Anglican, draws from Catholic (and later Calvinist) doctrine about Original Sin and the idea of the Fall. You see, to paraphrase the Colonial-era primer, through Adam’s fall, democrats all.
Modern people looking back at the founders and their worldview tend to focus on the known (or presumed/assumed) Deists, Baptists, and Quakers and to gloss over the very strong influence of the Congregationalists, Presbyterians, Lutherans, and certain sub-groups of Anglicans on the development of the ideas underlying the Republic. One of these ideas, and one that dovetailed well into the Enlightenment’s philosophies about government, was that of Original Sin and Adam’s Fall. Because in that theology, all Men are alike in depravity. No one is better because they were born to a gentry or aristocratic family. None were inherently inferior because they were born into slavery or into a family of peasants. All Men had fallen from Grace, all deserved damnation and no man is any better (or worse) than any other in the eyes of G-d. Only the mysterious, unknowable, and absolutely undeserved mysterious grace of G-d elected a few to be saved, and that not of their own goodness but purely by the will of the Most High. And no one alive could know who was, or was not, among that Elect. There were a few hints and clues, perhaps, but even then they might be false guides.
What does this have to do with the founding of the Republic? A good deal. Because not long before the first stirrings of what became the Revolution began, a revivalist preacher named George Whitfield preached up and down the Colonies. He could do this, pulling in converts and revitalizing churches of all sorts despite being Anglican himself, in part because the language of sin, the Fall, and the equality of mankind in sin was part of the common religious language. Not everyone agreed in all details (the Anglicans still preached orders of birth in society, the Quakers didn’t believe in innate depravity) but all were familiar with the concept. Think of it as sort of a background hum, to be ignored or not depending on one’s personal belief and inclination.
So what? I would argue that this background noise of the equality in sin of all men made the idea of the equality of all men before the law even easier to accept. And while a woman in Pennsylvania, say, might not believe in the concept of Double Predestination preached by her Presbyterian neighbor, she might be more receptive to the idea that all men are created equal and are endowed by their Creator with certain inalienable rights. When you add in the arguments about the need to reestablish the balance of powers between the Crown, the nobility and the people (executive, judicial, legislative) because of the corrupting nature of political power, and I think you can see how this fits into the mental world of the Early Republic, at least through the Second Great Awakening.
Thomas Sowell and other modern writers point out that the current elites believe in the perfectability of man on earth (a bit like the joke about Aeroflot seats re-shaping the Communist man). Those of us who are familiar with, or raised in, an older philosophical environment look back at Adam’s Fall and the ubiquity of sin, even if only as a useful metaphor, and know better. The Founders would have shaken their heads at the sheer vanity (and wrongness) of the very thought. All have sinned, but many could rise above it if encouraged (or occasionally poked, prodded, and/or dragged) into doing so. Thus a Constitution written for fallen men, not for angels.
I suspect a serious scholar of religion in America could do a much better job of framing these ideas than I can. And religion was by no means the only driving force in the Colonies drift, then run, then fight, away from Great Britain. But several Christian doctrines played strongly into the thoughts and understandings that eventually led to the break, including that of Original Sin.
For further reading: Mark Noll, America’s God
Michael Barone On Two Wings
Peter Thuesen, Predestination: The American Career of a Contentious Doctrine
David H. Fischer, Albion’s Seed
Bernard Bailyn To begin the World Anew