As I mentioned in my DC letter, I recently finished "Head and Heart" by Gary Willis. Willis has written often on American history and won a Pulitzer for his book on Lincoln's Gettysburg Address.  In this book he traces the history of the influence of religion on America as a back and forth movement between evangelical fervor and "enlightenment" thought, i.e., a view that seeks to be highly rational, emphasizing tolearance of various opinions.  So, for example, the revolutionary period followed a time of a religious revivalism known as the "Great Awakening