"No historian would doubt that Lincoln was a man of his times," says Dunbar, author of "A Fragile Freedom: African American Women and Emancipation in the Antebellum City." "He was a racist, and never truly believed that blacks could live in America after emancipation."
Other historians say Lincoln was evolving into the leader that Spielberg depicts.
The historian Gates once wrote that Lincoln initially opposed slavery because it was an economic institution that discriminated against white men who couldn't afford slaves. Two things changed him: The courage black troops displayed in the Civil War and his friendship with Douglass the abolitionist.
"Lincoln met with Douglass at the White House three times. He was the first black person Lincoln treated as an intellectual equal, and he grew to admire him and value his opinion," Gates wrote.
Gilpin says Lincoln was great not only for what he got right, but because he could admit what he got wrong.
"You dream of a president like that," Gilpin says. "Not only was he a brilliant manipulator and reader of public opinion, but he had the capacity for growth. He came into office because he was a moderate but he turns out to be the Great Emancipator."
Lesson: Lincoln led an epic battle against slavery, but the abolitionists lit the fuse.