Really...
But he WAS practicing there at one time, he worked in a law firm in Chicago.
Or was he only doing para-legal type work there?
(Shamelss, knee-jerk speculation)
I think that would be admission to the State Bar of Illinois. Now I'm wondering if he took the bar exam. Required for admission.
Here’s a piece about his actual practice of law from Chicago
http://www.suntimes.com/news/politics/obama/700499,CST-NWS-Obama-law17.article
Not certain why he let his license to practice lapse- that may be SOP with (some) politicians?