Colonization was the idea that once slavery ended African-Americans should be encouraged - or required, in some people's view - required to leave the country. It's part of an attitude toward the abolition of slavery which says America should not be a slave society, but it can never be a multiracial society. You can never have free black and white people living together.

Whenever you think of Lincoln as a historian, in his own mind, he becomes the Great Emancipator. This is his role in history henceforth. He was an ambitious man who wanted to make an impact on history, and this is how he did it.

For historians, hindsight can be a treacherous ally. Enabling us to trace the hidden patterns of past events, it beguiles us with the mirage of inevitability, the assumption that different outcomes lay beyond the limits of the possible.

Look, Mrs. McGillicuddy, it's not my fault your son jumped out a dorm room window on Christmas eve. I've written over fifty books as a Columbia professor, all right? You don't do that by holding hands with every at-risk undergraduate who says he's homesick, or he's turning gay, or the dog ate his term paper. I write about Lincoln, and freedom, and great ideas. I don't always have time for students. It's like Dean Martin used to say: if you want to talk, go to a priest. Hey -- what's the gun for?

Who owns history? Everyone and no one--which is why the study of the past is a constantly evolving, never-ending journey of discovery.

Whatever Lincoln's racial views, which are not totally modern and egalitarian in many ways, he believes blacks should have this natural right to improve their condition in life and slavery denies that to them.

I think here is the irony of American history. We don't have an established church. When you have an established church nobody takes religion as seriously as we do here. We have a free market in religion. The religious groups are competing with each other.