I think the word "Christian" is what trips the argument up, because most wealthy free thinking men of that time had a barely disguised disgust with the human structures that had perverted Christianity into the basis of armed conflict and draconian persecution of civil liberties. They understood that the belief systems of folks arriving from the old world were highly diverse.
The writings of most of the founding father displayed at best an uneasiness and at worst and outright condemnation of explicitly writing Christian terminology into the founding document. They went out of their way to say that we need to respect and include value systems from all religions, not just the predominant protestant Christianity of the late 1700s North American British Colonies. A few examples:
Thomas Paine
"With respect to what are called denominations of religion, if every one is left to judge of his own religion, there is no such thing as a religion that is wrong; but if they are to judge of each other's religion, there is no such thing as a religion that is right; and therefore all the world is right, or all the world is wrong."
Thomas Jefferson Autobiography
"an amendment was proposed, by inserting the word "Jesus Christ," so that it should read, "a departure from the plan of Jesus Christ, the holy author of our religion;" the insertion was rejected by a great majority, in proof that they meant to comprehend, within the mantle of its protection, the Jew and the Gentile, the Christian and Mahometan, the Hindoo, and Infidel of every denomination."
And to you point here:
Quote:
Where it gets more interesting in the writings of the founders (echoing classical political theorists and philosophers) is that they were adamant that a person could not have public virtue if they were incapable of private virtue. In other words, a person was not fit to rule others if he was not able to rule himself. Private virtue within the population is the only guarantor of liberty.
John Locke zeroed in very specifically on private virtue not being a product of a single religion. From his 1689 letter concerning toleration
"
Secondly, no private person has any right in any manner to prejudice another person in his civil enjoyments because he is of another church or religion.
All the rights and franchises that belong to him as a man, or as a denizen, are inviolably to be preserved to him. These are not the business of religion. No violence nor injury is to be offered him, whether he be Christian or Pagan."
He basically shouted rights of man are not the business of religion.
This is why I am skeptical of the belief that, despite the founding fathers great efforts to stay mum on the role of religion in society, there was actually a purely Christian influence to the document. If it is anything, it reflects the wholesale mistrust of man in general or governments in particular to interpret and apply religious thinking in a manner that does not result in terrible outcomes.
And I don't blame them because Europe and the colonies were one very long running series of horrible and bloody religious civil wars and/or harsh punishments from deviations of state run religious laws.