Virtually all the evidence that attempts to connect a foundation of Christianity upon the government rests mainly on quotes and opinions from a few of the colonial statesmen who had professed a belief in Christianity. Sometimes the quotes come from their youth before their introduction to Enlightenment ideas or simply from personal beliefs. But statements of beliefs, by themselves, say nothing about Christianity as the source of the U.S. government.
There did occur, however, some who wished a connection between church and State. Patrick Henry, for example, proposed a tax to help sustain "some form of Christian worship" for the state of Virginia. But Jefferson and other statesmen did not agree. In 1779, Jefferson introduced a bill for the Statute for Religious Freedom which became Virginia law. Jefferson designed this law to completely separate religion from government. None of Henry's Christian views ever got introduced into Virginia's or U.S. Government law.
Unfortunately, later developments in our government have clouded early history. The original Pledge of Allegiance, authored by Francis Bellamy in 1892 did not contain the words "under God." Not until June 1954 did those words appear in the Allegiance. The United States currency never had "In God We Trust" printed on money until after the Civil War. Many Christians who visit historical monuments and see the word "God" inscribed in stone, automatically impart their own personal God of Christianity, without understanding the Framers Deist context.
In the Supreme Court's 1892 Holy Trinity Church vs. United States, Justice David Brewer wrote that "this is a Christian nation." Many Christians use this as evidence. However, Brewer wrote this in dicta, as a personal opinion only and does not serve as a legal pronouncement. Later Brewer felt obliged to explain himself: "But in what sense can [the United States] be called a Christian nation? Not in the sense that Christianity is the established religion or the people are compelled in any manner to support it. On the contrary, the Constitution specifically provides that 'Congress shall make no law respecting an establishment of religion or prohibiting the free exercise thereof.' Neither is it Christian in the sense that all its citizens are either in fact or in name Christians. On the contrary, all religions have free scope within its borders. Numbers of our people profess other religions, and many reject all."
The reality however is that the US was a Christian nation, an overwhelmingly Protestant nation in fact until the 20th century, but not with a Christian or Protestant government (whatever the latter might be, which I cannot imagine, given all the sects). The amazing thing, is that with all its vast wealth and power, unlike any other such place, America retains an out of the box interest in matters of faith. The Puritan seed is alive and well on the fruited plain. It is what give this nation "virtu," so says this near atheist.
That may be true but in 1811 this case, People v. Ruggles; (1811) the Supreme Court said this:
"... Offenses against religion and morality ... strike at the root of moral obligation, and weaken the security of the social ties ... this
[First Amendment] declaration ... never meant to withdraw religion ...
and with it the best sanctions of moral and social obligation from all consideration and notice of the law ..." Supreme Court, 1811.
And in 1844, Vidal v. Girard's Executors:
"The purest principles of morality are to be taught. Where are they found? Whoever searches for them must go to the source from which a Christian man derives his faith - the Bible.
United States Supreme Court, 1844.
Even state courts weighed in:
"... What constitutes the standard of good morals? Is it not Christianity? There certainly is none other. Say that it cannot be appealed to, and... what would be good morals The day of moral virtue in which we live would, in an instant, if that standard were abolished, lapse into the dark and murky night of ... immorality." Supreme Court of South Carolina, 1846
"... For whatever strikes at the root of Christianity tends manifestly to the dissolution of civil government ... because it tends to corrupt the morals of the people, and to destroy good order." Supreme Court of New York, 1811.
And the Senate Judiciary Committee:
"... Religion ... must be considered as the foundation on which the whole structure rests ... In this age there can be no substitute for Christianity... the great conservative element on which we must rely for the purity and permanence of free institutions." Senate Judiciary Committee, 1853