Herman Cain has defied the political odds so far in the face of campaign adversity, and it looks as if he has the GOP’s conservative base to thank for it. The last month of Cain’s presidential campaign has read like a textbook for how to doom a candidacy: having to deny allegations of sexual harassment, bungling important foreign-policy questions while saying he’s not “supposed to know anything” on the subject, releasing a bizarre Web ad and canceling an editorial board meeting with a key New Hampshire newspaper. And yet, in an Iowa State University poll released Thursday, the former Godfather’s...