"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 subterranean support from a politically radioactive secret society)."
Jonathan Chait at New York reacts to Donald Trump's difficulty in disavowing white supremacists (and argues that Trump is the consequence of conservatives' historical use of racism).
And Philip Bump at The Washington Post reminds readers of the arrest of Trump's father at a Ku Klux Klan rally in 1927.