Miliband has friends in Minnesota. “They’re really scared,” he says. “I texted and said, ‘Really thinking of you.’ And I got replies saying, ‘It’s really scary, but the unity is extraordinary.’ ” Miliband lived in the United States for a period as a boy when his father was an academic there. “I first went to America in 1977, 50 years ago nearly, and it felt like ‘Out of many, one’ — E pluribus unum — really was the story of the day. We’re a long way from that. It’s not a fragile state, but it’s in a fragile state. The...