Below is a list of books and articles that may be of interest:  

Church, Forrest, Ed. The Separation of Church and State: Writings on a Fundamental Freedom by America`s Founders. Beacon Press 2004  

Sunstein, Cass. The Second Bill of Rights.  Basic Books.  2004 

Lerner, Michael.  The Left Hand of God.  Harper.  2006. 

Albright, Madeleine K. The Mighty And The Almighty: Reflections On America, God, And World Affairs. HarperCollins,  2006.   

Carter, Jimmy. Our Endangered Values: America’s Moral Crisis.   Simon & Schuster, 2005. 

Wilentz,  Sean. “The Worst President in History?”  Rolling Stone, April 2006. 

Wallis, Jim.  God’s Politics: Why the Right Got it Wrong and the Left Doesn’t Get It.  Harper. 2005