Religion and the Founders - Michael Novak

Religion and the Founders: "Indeed, the Founders saw the cultivation of religious sentiment as the ultimate safeguard of American liberty. They knew that liberty could only prosper among moral citizens, whose practice of self-government in their private lives was a necessary prerequisite for its exercise in public. They believed that even if it were possible for certain individuals to behave morally without believing in God, on the whole an entire citizenry could not long keep its moral bearings without the guidance of religious faith."

Freedom depends on morality, and morality depends, for the most part, on belief in God.