Former Vice President Joseph R. Biden returned Wednesday to his longtime habit of gilding his academic credentials. Mr. Biden claimed to be an Ivy League professor at the end of a nearly 8-minute, rambling answer to a question from an 18-year-old on what he was doing to appeal to young voters who may favor Sen. Bernie Sanders for the Democratic presidential nomination. “There’s a lot we can do. When I left the United States Senate, I became a professor at the University of Pennsylvania,” he said, bringing up that fact to claim that his professorship established a bond with college...