Religious but not Christian Underpinnings:

No doubt the American Revolution and subsequent Constitutional Founding offered theistic and religious rationales for their ideals. The problem for America's Founders was the entrenched religion was traditional Christianity and such religion spoke little to the needs of what they were trying to accomplish. The other side against whom they rebelled possessed the same religion. This led to what Mark Noll has termed an "importing" of extra-biblical ideas into the Christian religion during America's Founding era to help establish republicanism.

Ellis Sandoz's collection of Founding era sermons aptly illustrates this phenomenon. Take for instance, Bishop James Madison, cousin of the Founder with the same name. Bishop Madison was I believe, unlike his cousin, an orthodox Christian. Though he was suspected of being an "infidel" and indeed was close to many of those infidel Whigs whose ideas were primarily responsible for Founding American government. I've heard it said that the biblical worldview influenced even non-Christian Enlightenment thinkers like Jefferson and Franklin. That's true to an extent. But so is the converse: Non-Christian Enlightenment principles, so needed as they were, influenced the views of orthodox Christians like John Witherspoon, Samuel Adams, Samuel Langdon, and Bishop James Madison.

Here is one such sermon by Bishop Madison where he thunders against tyrannical leaders and praises liberty, equality, and fraternity. As Sandoz notes Madison was "[a] strong advocate of independence, he went so far, we are told, as to speak of the republic—rather than kingdom—of heaven." The Bible however, speaks of a kingdom of heaven, not a republic. And the Ancient Israelites did not have a republic, but a theocracy. This perfectly illustrates the "importing" of a-biblical Whig ideology into the Christian religion. And the Whigs did the same "reading in" 18th Century ideas to the ancient Greco-Roman democracies and republics of antiquity as well.