All decent Americans have an obligation to condemn the violent bigotry of the Nazi and KKK demonstrators in Charlottesville, Va., or wherever else they spew their poisonous and threatening rhetoric. But President Trump has a special obligation to single out for condemnation, and distance himself from, individuals and groups that claim (even if falsely) to speak in his name, as the racist provocateurs in Charlottesville did.

David Duke, the notorious bigot, told reporters that white nationalists were working to “fulfill the promises of Donald Trump.” Richard Spencer, the founder of the Daily Stormer (a not-so-coded homage to the Nazi publication Der Sturmer), attributed the growth of the ultra-nationalist alt-right to the Trump presidency: “Obviously the alt-right has come very far in the past two years in terms of public exposure … is Donald Trump one of the major causes of that? Of course.”