The Founding Fathers were mostly Christian but not all. Their ideas about liberty were more eclectic than Christian in particular, despite what your televangelists will say. (Historic revisionism works both ways!)
Benjamin Franklin is one of the more notorious Deists, and George Washington supported Thomas Paine
after he wrote
Age of Reason.
"History will also afford frequent opportunities of showing the necessity of a public religion...and the excellency of the Christian religion above all others, ancient or modern." Benjamin Franklin "
If Franklin was a 'deist', why would he promote the Christian faith?