"It cannot be emphasized too strongly or too often that this great nation was founded, not by religionists, but by Christians, not on religions, but on the gospel of Jesus Christ!" (Patrick Henry).
The same men who authored the First Amendment, did so with the desire to promote Christianity. The First Amendment states - "Congress shall make no law respecting an establishment of religion or prohibiting the free exercise thereof." The point was to keep the government from completely controlling Christianity. It was not the desire of the orginal authors to call any belief system a religion. Nor was it their desire to let humanism, atheism, and other false religions thrive.
What other source is more equipped for the exercise of authority over nations than the Bible? Patrick Henry understood that America was founded upon the ideal that the gospel in itself had the power to give him "liberty or death." He chose liberty. His formula for liberty was America and the gospel.