They're probably thinking that they don't have a viable candidate with ANY chance of actually WINNING the election so they drag old Keyes out so he can constantly hammer the democrats in general with republican wedge issues.

Or, if you prefer something a little more conspiracy theoryish, perhaps they have a plan to give Keyes a little "help" in the Illinois election as a test run for the presedential election shenanigans. Now if you'll excuse me, I need to go find my tinfoil hat. :)