What does it mean to be an American? By what texts do we define ourselves as "We, the People"? Since our country's founding, Americans have debated the speeches and tracts sacred to our founding, from the Exodus story to the Declaration of Independence. Indeed,  Americans are defined by the diversity of our voices, by our ability to remain united while we disagree through our civic discourse.   In this election year, politicians and pundits constantly debate the "true" meaning of America's core canon, asking what the Founding Fathers or Martin Luther King, Jr. or Eleanor Roosevelt would think of immigration reform, or affirmative action, or birth control. In his new book, author and professor Stephen Prothero  writes, "To answer these questions, they have returned, over and over again, to certain core texts. These core texts constitute a de facto canon of American public life." Prothero has collected these core texts in his new book, "The American Bible."