This is not a development type of article and I do not want politics to invade this thread but this nice article from Salon give a good history of Illinois and Chicago politics.
http://www.salon.com/opinion/feature/2008/01/14/obama/
Chicago is Barack Obama's kind of town
...
"Part of what attracts me about Illinois generally is I think it's a microcosm of the country: north, south, east, west, black, white, urban, rural, southern, northern," Obama once said. "For somebody who cares deeply about the country, and about the issues and struggles this country's going through, I can't think of a better laboratory to work on some of the pressing issues we confront."
Barack Obama came to Chicago decades after the Great Migration, but for a young black man with political ambitions, it still turned out to be the promised land.