"Lincoln" is gradually opening nationwide and as it does, the accolades being bestowed on Daniel Day-Lewis for his depiction of the 16th president grow louder and louder. But at the same time, questions are arising about the film's depiction of African Americans, and whether black characters should play a larger role in the story. Kate Masur is among those expressing concern. Masur is an associate professor of history at Northwestern, and the author of "An Example for All the Land: Emancipation and the Struggle Over Equality in Washington, D.C." Dylan Penningroth  is an associate professor of African American History, legal history, and U.S. social history at Northwestern and the author of "The Claims of Kinfolk: African American Property and Community in the Nineteenth-Century South."