[Pelham]

Good post. And some often ignored history of the treatment of blacks in the North can be found here

An excellent new book on the polarization that led to the war is Thomas Fleming's A Disease in the Public Mind: A New Understanding of Why We Fought the Civil War

[Verginius Rufus]

Alexis de Tocgueville in Democracy in America expressed the opinion that racial prejudice was stronger in states where slavery had been abolished. He was in Philadelphia on an election day and noticed that no black men were coming to vote. They could vote legally but they were afraid to exercise their right to vote.