Great post by Ed Brayton on the little understood theological universalism of our key Founding Fathers. One Dispatches' commenters aptly termed the Founders' religious terminology as "pure syncretism."
Dr. Gregg Frazer addresses the Founders' universalism in his Ph.D. thesis. He argues that Joseph Priestly influenced the Founders in this regard as well. His section on Priestly questions the soundness of the Founders' theistic rationalist theology. Given that Frazer is an orthodox Christian, one should expect such criticisms. Such criticisms, though, are only slightly peppered throughout his thesis, the overall tone of which simply describes the Founders' belief system without "judging" it. Anyway Frazer writes:
Priestly...reflects a level of naivete also exhibited by the key Founders. Namely, everyone should simply be able to set aside their fundamental beliefs about the particular identity and nature of God and accept the Unitarian vision of God as a sort of universal supernatural entity who appears in various forms to those of various traditions.
I'll let the theologians debate the soundness of the Founders' theology. Their religion appeals to my sentiments more so than orthodox Christianity. But both orthodox Christians and atheists would remind me here that just because something sounds nice doesn't make it true. Certainly though, the Founders' theological universalism is not consonant with orthodox Christianity, which believes there is just one way to God.