From New York Magazine–written by Jonathan Chait:
Trump, of course, is lying when he claims to be unaware of David Duke. Duke is a famous figure whose ability to compete for statewide election in Louisiana drew national attention twenty-five years ago. Trump himself has expressed familiarity with (and disavowed) Duke in the past. The political logic of Trump’s evasiveness is bizarre. Yes, Republican voters respond to dog-whistle racism. And yes, racial resentment is deeply embedded in the popular appeal of conservative politics. But Republicans are overwhelmingly convinced of their own racial innocence. There is no reason to believe they wish to tolerate open association with the KKK.
More interesting is Trump’s language. Four times in the interview, he repeats the phrase “I know nothing.” That is the exact wording used by 19th century nativists. The “Know-Nothing Party” is sometimes misremembered in the popular imagination today as signifying ignorance. In fact, the phrase was used by nativists who belonged to secret societies pledged to support only native-born Protestants for public office. When questioned about the groups, members were instructed to state “I know nothing.” It is striking to see modern nativist Donald Trump repeat this precise formulation as an answer to an analogous question (his sub-terra support from a politically radioactive secret society.)
Possibly Trump is making a clever historical reference that he will later explain when he reveals that his entire political profile from 2011 through 2016 was a form of guerrilla theater designed to smoke out the widespread appeal of Republican racism. Or else, more likely, he is even stupider than anybody previously believed.