From the very first day, Steve Bannon made an impression. In a Harvard Business School classroom of about 90 people in 1983, he took a seat in the “skydeck” — a spot at the top giving him a view of the entire class. The marketing professor pointed up at Bannon, calling on him — without warning — and asking that he present the case study they were supposed to have read before coming to class. The case was on Fieldcrest blankets, the acrylic bedding available at most department stores. “This,” Bannon began, “is a sleepy industry.” The tense classroom cracked...