Jefferson's view was that the virgin birth of Christ was as unlikely as the mystical generation of Athena from the skull of Zeus. He was not a Christian either, except as a proponent of the philosophy of Christ. But Christianity without Spirituality is not really Christianity. Whatever the mans merits or faults, he was not a Christian as Christianity is usually defined.
Etc.
We can quibble over details all day long, but I have not the slightest doubt that Jefferson, Franklin, Madison, et al., are firmly within the JudeoChristian cultural orbit. The first two especially were prime figures of the American Enlightenment. Notwithstanding they believed in a Creator who is the source of unalienable human rights and, because we are his creatures, made in His image, in the sovereign dignity of every human person. Their own lives demonstrate that faith and reason aren't the mutually opposed irreconcilables as we are being taught today by such notables as Dawkins, Harris, Dennett, and Hitchens. There is absolutely no doubt that these Framers were not atheists; nor Buddhists, Hindus, or Muslims either. Granted the fact that they departed from certain dogmas on rationalist grounds may make them "heretical" in some people's eyes. Nonetheless they were Christian in fundamental belief. Ellis Sandoz suggests that they were generic Christians, or "Providential Christians." Indeed, my quote upthread from John Adams illustrates and supports this view.
Another thing worth considering is the history of Christian religious revival in America. The first Great Awakening was in the early 18th century; the second in the early 19th. The first ultimately spent its energies in the American Revolution itself. The second, in the Civil War, which ultimately boiled down to the institution of slavery. The abolition of slavery and the slave trade was preeminently a Christian project, first in England, in the crusade led by William Wilberforce; and then later in America. The Christian belief that all men are created equal in the sight of God is what essentially motivated this quest.