Without challenging the words of anybody in the preceding ten posts I would not the following:

Christianity nor any religion has remained immutable from its founding. The tender sympathies of our founding fathers with respect to Christianity as promoter of liberty represents well over a millenium and a half of developing understanding, most importantly culminating in the period of rationalism surmounting theology called The Enlightenment. Christianity has still been used to buttress the Divine Right of Royalty.

One fascinating aspect of the law as we practice it is the considerationi of motivation toward establishing a crime and determining a penalty: viz. If I was careless on a job and dropped a wrench and it hit Mr. Smith in the head and sent him to the hereafter, I may not be put on trial at all, and if I am, it will be over claims of negligence or indifference. If I creep up behind Mr. Smith and brain him with that same wrench, I may go on criminal trial for first degree murder with my life on the line. Mr. Smith is just as dead either way, but I think every human being on earth would perceive justice in the distinction being made as to how he came to be dead.

I have the same feeling about the Ten Commandments in public. If they crop up in an illustration or as part of a display of the concepts behind our judicial system, I have no problem with 'em. If it comes from an avowedly activist source, seeking as an act of power to install them, I consider it to be as the good Reverend said at the outset of this thread "blasphemy".

I believe the framers and our American forefolk used the language of God in their everyday talk. Many of us American descendents use that sort of language in our everyday talk. But like ourselves, they were creatures of their time (lucky for us). There is a bit of selective quotations in the above posts, to bring in Jesus Christ. I have seen numerous references to our forefathers and it is clear that some of them, not all of them, appreciated the wisdom of Jesus' words in the New Testament without necessarily subscribing to the theology of him as the Son of God. Furthermore, there are some explicit wordings I'd call to your attention: From the Declaration: "The laws of nature, and of nature's God". This is a deist concept of God, explicitly not Christian, and ties into the new age in which Galileo established that the Church (any church) was a poor source of astronomical theories, and that Isaac Newton and many others had established that the world as we know it operates on highly logical and mathematical principles, so that God is not necessary to make every Sparrow fall, God has only(!) to establish the inverse square law of gravitational attraction.
I think we all of us are even now incredibly lucky to have had such great people at work two hundred forty years ago. They were Christian folk, but they were no 'mere' Christian folk.