In the last 150 years, a remarkable theological shift in doctrine has occurred. Some of the older orthodox writers on the history of doctrine might have reported it had they been alive to witness it, but none of the moderns have commented on it.
For 1900 years, with increasing frequency after the Reformation and leading up to the American Revolution, the Augustinian doctrine of "the Depravity of Man" has been a premise in reasoning leading to the conclusion that the powers of the State must be limited: that a separation of powers must be woven into constitutions, and the path to power riddled with the landmines of checks and balances.
Why? Because man's fallen nature meant that he could not be trusted with centralized political power.
To be sure, while Christian theologians were using the Depravity of Man to support the state, many others were using Enlightenment premises on the goodness and perfectibility of man to attack authority and community.
After the Civil War, following the great American theologian Abraham Lincoln, the Depravity of Man became the Benedict Arnold of dogma. The doctrine became a turncoat premise in syllogisms buttressing an increase in the paternalistic powers of the State. Whereas Man's "depravity" earlier meant that man could not be trusted with power (whose corrupting influences Lord Acton saw residing in man himself), the modern doctrine indicts the fallen and untrustworthy masses ("the People") and supplicates the sinless and infallible State for social salvation. Because the masses are depraved, you see, the centralized state needs more power to control them.
Here are links to both sides of the coin: first, why the Depravity of Man formerly and rightfully meant the need to limit the State, not increase its scope; and second, why the doctrine of Man's Depravity does not cancel out the fact that man is created in God's Image, and that God intends to save man's culture, not just his soul.
Depravity and Statism
Depravity and Social Order