Again, our country is great because it was founded by a group of people versed in the Enlightenment. The Western tradition of importance is the legacy of Athens, not Jerusalem.
The nature of their beliefs must be understood with respect to the time they lived. Jefferson cut all of the miraculous hogwash from the Bible, Washington refused to take communion, in the time period, they were scandalously anti-religious.
But that's all distraction. Even the Founders that were clearly Christian had the foresight to leave that nonsense out of the founding documents. There is no Biblical source for the content of the Declaration and Constitution. The absurd 10 commandments are absent, the god-awful mishmash of ignorant rules in the Old Testament is absent, and nothing Jesus said is codified in our National laws.
Enlightenment philosophy, not iron-age mysticism, is the foundation of our nation.