I believe that Ryan is turning traditional political mores on their head with his move. His hatred of Chicago Dems goes back to Daley's obstructionist tactics. He also is no longer enamored with the Republican party, feeling (correctly, I think) that the Repubs sold him out when the bribery scandal hit. It's not as if there hasn't been a history of corrupt campaigns in Illinois. Ryan had to pay the piper for the sins of those before him, and his loyal hack-soldiering left him out to dry. Ryan can get back at suburban republicans, the corrupt Chicago machine and whinging downstaters (embodied by Jim Ryan's disloyalty) in one fell swoop, along the way garnering a nomination for the Nobel prize and a probable academic appointment with which to further feather his nest.