See post 9, he had a conflicting commitment in Chicago. I doubt the judge would delay the trial of two Hamas supporters so a witness could appear at a Holocaust denial conference. I think he has time to make it though. I can't believe DePaul is considering giving him tenure. Of course I couldn't believe they hired them in the first place.
This is a tough competitive world for the colleges. Getting a well known even if controversial figure makes the school more visible and interesting. And it enhances the image of academic independence.