Obama first played a perfuming role as a state senator. His mentor, Emil Jones, the machine-made president of the Senate, allowed him to sponsor a minor ethics bill. In return, Obama made sure to send plenty of pork to Jones’s district. When asked about pork-barrel spending, Jones famously replied: “Some call it pork; I call it steak.”

Obama repaid the generosity. When he had a chance to back clean Democratic candidates for president of the Cook County board of supervisors and Illinois governor, he stayed with the allies of the Outfit. The gubernatorial candidate he backed, Rod Blagojevich, is under federal investigation, in part because of his relationship with Tony Rezko, the man who helped Obama buy his house.

The Chicago way has delivered politically for Obama even this year. Ninety per cent of his popular-vote lead over Hillary Clinton comes from Illinois, and two-thirds of that 90 per cent comes just from Cook County.