On the one-year anniversary of the violence in Charlottesville and the killing of Heather Heyer, an anti-Nazi protester allegedly mowed down by a white nationalist, President Trump reminded us he is incapable of treating white nationalism as a singular evil or of offending his white-grievance-obsessed base. Trump unleashed a furious backlash a year ago when he engaged in jaw-dropping moral equivalence, saying there were very fine people, on both sides (meaning both Nazi sympathizers and anti-Nazi protesters) and later claiming there was blame on both sides. Saturday, he gave the same wink to white grievance mongers, insisting on Twitter,...