[Gophack]

The U. S. Constitution's lack of a Christian designation had little to do with a radical secular agenda. Indeed, it had little to do with religion at all. The Constitution was silent on the subject of God and religion because there was a consensus that, despite the framer's personal beliefs, religion was a matter best left to the individual citizens and their respective state governments (and most states in the founding era retained some form of religious establishment). The Constitution, in short, can be fairly characterized as "godless" or secular only insofar as it deferred to the states on all matters regarding religion and devotion to God.

Found this article by a scholar on our Founding, thought you might be interested. The full article is here:

A Godless Constitution?: A Response to Kramnick and Moore

[Gophack]

According to John Adams, a founding father and the second President of the United States:

[W]e have no government armed with power capable of contending with human passions unbridled by morality and religion. . . . Our constitution was made only for a moral and religious people. It is wholly inadequate to the government of any other.