I wouldn't say they run Cook County, per se. They run Chicago like nothing else, though. Mayor Daley is practically royalty--he's even a White Sox fan and people on the North Side vote for him because he's (D). That's crazy, for those who don't follow Chicago baseball.
Many of the suburbs of Chicago in Cook are mostly Republican. By default, however, since there are so many people in the actual city, Cook is run by Democrats. I can't remember the last Republican who was in a major political position in the county.
Also, I wouldn't say the machine is stealing votes anymore like they were in the 1960s.
Yeah everything here is true. Suburbs you have a lot of Republican parents with Democratic teenagers because "WE HAVE TO MAKE A DIFFERENCE AND BE COMPASSIONATE," but you get that most everywhere.
You'd think that, as would I, but isn't Daley getting into trouble for hiring construction companies to work on Midway and O'Hare with some sort of political ties?