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.

In a democratic society, as Max Weber said, what is possible is only possible because some people have demanded the impossible. The abolitionists helped to create a public discourse in which men like Lincoln become possible. That doesn't mean Lincoln is an abolitionist. It means there is a public opinion out there which is being influenced by antislavery sentiment.

Freedom has been privatized - it is how you dress, what your sexual orientation is, choosing your own life. That's fine. But that is not what Thomas Jefferson was talking about.

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.

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 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.

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.