University of Pennsylvania president Amy Gutmann threw her annual Halloween costume party at her home Tuesday night. Among the guests was Saad Saadi, who came dressed as a suicide bomber, complete with plastic dynamite strapped to his chest and a toy automatic rifle. Worse, Gutmann posed with Saadi! An obvious question: would Gutmann have posed with a guest--or even allowed him into her house--if he'd dressed as Adolf Hitler or a Nazi SS officer? A KKK member? But in modern liberal circles, posing as a Palestinian suicide bomber (see his kefiya) is just fine. After all, he mainly tries to...