Sources such as the Chicago Daily Law Bulletin, the Illinois Bar Journal, the Chicago Tribune, the Springfield Journal-Register, the Capitol Fax Blog, and law reviews on Lexis or Westlaw may provide useful. For access to Chicago newspapers, see the Library's Chicago Newspapers guide.
The Daily Whale is a great source for news and information about law and politics in the Chicago area. To sign up to receive daily emails, Ask a Law Librarian.
If you run into problems compiling a legislative history for an Illinois statute, contact the Illinois State Archives, Reference Service (217) 782-4866. Provide them with the Public Act number and explain that you have consulted the transcripts of debates and want to make sure there is no additional information.