When a society jerks into extremism, so does its fashion. Think about Maoists, Nazis, Klansmen, and jihadists—what do they all have in common? A look. Extremism starts with how people look and how society feels. Sometimes it creates literal uniforms: Olive tunics and caps with red stars, red armbands, white pointed hoods, polo shirts and tiki torches, MAGA hats.

