The United States is divided along the fault line of color. We call it racism. Forty years ago, in 1964, the South - the states that had left the Union to fight against Abraham Lincoln and to protect slavery and states rights - was still totally segregated. Fear was the staple crop that supported the cotton curtain of Jim Crow.

But racism and segregation were not confined to the South. In Illinois, blacks could vote and the rules of Jim Crow were subtle. But in the 1950s, as more than 300,000 southern blacks poured into Chicago, the city became entirely segregated along residential lines. The fight was not who could sit where on a bus, but where whites and blacks could live. With housing went schools. With schools went education and with education went jobs.

Racism wore different faces, with different consequences, in the different regions.