Yeah, being from Illinois it's really interesting.
I think the main issue Barack has is that he is from what could be argued to be the most corrupt state political system in the nation. Which means there is no way he can be squeaky clean even if he tries. He has to lie down with dogs because it's part of the job. He's going to be waking up with fleas. It's unavoidable. However, the matter is, how hard did he try to avoid the fleas, or did he embrace the fleas.
In other words, you could be the most honest person in the world, and there is no way you can avoid the filth that is Illinois political pool. However, you can definitely try your damndest to stay in the shallow end. It'll be interesting to see what happens. I'm leaning toward's Obama's feet being able to touch ground in this, but I won't be overly shocked if he's revealed to be treading water or actively drowning.
Now I don't think any politician is squeaky clean anyway. So an Illinois politician at there best, is little worse than any other politician. But an Illinois politician at their worst, is something to be afraid of.