"A house divided against itself cannot stand."
I believe this government cannot endure, permanently half /slave/ and half free.
I do not expect the Union to be dissolved -- I do not expect the house to fall -- but I do expect it will cease to be divided.
It will become all one thing or all the other.
When Lincoln said those words at a Republican state convention, he wasn't just making another campaign speech. He was using the political forum to provide guidance to the nation by outlining it's main task in the next decade. I think Obama's Tuesday speech on race in America will one day be seen in a similar light.
And like Lincoln's speech, Obama wrote it himself. The last time an American politician wrote a major speech himself, other than Obama, was Nixon in 1969. That's how rare it is! He just took two days from the campaign and wrote it himself.