“Starting on [October] 29, without rest, we’ll start working to take down [media group] Globo, [newspaper] Folha [de S.Paulo] and all public enemies! Got it?,” wrote Olavo de Carvalho, a self-proclaimed philosopher who has become the mentor for a new right-wing generation in Brazil. He hates the label of “alt-right guru” he has been given, referring to himself as a “mere observer of reality.” But the truth is that thousands of Brazilian right-wingers look up to him as their political guide.
Based in the U.S. since 2005, Mr. Carvalho shares his adopted country’s passion for guns and carries himself...