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.

I don't [even] know the number of books on Abraham Lincoln. Ten thousand, twelve thousand? I have seen various numbers. It seems like every generation is always trying to come to terms with Lincoln.

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?

Lincoln is such an iconic figure in American history. He seems to reflect so many elements of American culture that we consider essential, whether it's the self-made man, the frontier hero, the politician who tries to act in a moral way as well as in a political way, Honest Abe. His career raises these questions that are still with us, the power of the federal government vis-à-vis the states, the question of race in American life, can we be a society of equals? There are so many issues central to Lincoln's career that are still part of our society one hundred and fifty years later.

If you are going to abolish slavery, that opens up all these other questions: what system of labor is going to replace slave labor? What system of race relations is going to replace the race relations of slavery? Who is going to have power in the post-war South? The Emancipation Proclamation doesn't answer that question, but it throws [it] open.

You pick up very well-known books on Lincoln [and] you will find almost no reference to his long-term belief in colonization. Why? Because it doesn't fit the image of the Great Emancipator. It doesn't fit the retrospective view we want to have of Lincoln as the man who was the moralist in politics, who came into office committed to ending slavery and waited to sign this document.

I admire Lincoln enormously and I think what's interesting about Lincoln is how he changes, it's not that he held the same view throughout his life.