Our nation was built by committed Christians. Even those who were Deist promoted Biblical morality 100%. Most of the original states had state churches too. Rhode Island was the first where there was religious freedom. Georgia and Pennsylvania followed suit. The Federal government can't establish a church over all states but each state can if they so desire. You don't get America without Christianity. I don't promote state or national churches but facts are facts.
The founding fathers would be appalled at how immoral we are, how large we have allowed the government to get, income taxes, the Federal Reserve, and how many ways we start and all without Congressional approval. They would probably also be appalled that we give the right to vote to non-property owners.