This goes back to Sister Souljah. She was the activist who, in 1992, was asked by Los Angeles Times about violence against whites by blacks in the riots that year in the City of Angels. Was such violence a “wise reasoned action,” she was asked. “Yeah, it was wise,” she answered. “I mean, if black people kill black people every day, why not have a week and kill white people?” Bill Clinton, then campaigning for president, famously responded by saying that if one “took the words ‘white’ and ‘black,’ and you reversed them,” one might think that David Duke was speaking.

That became known as the “Sister Souljah moment” and helped convince Americans that Mr. Clinton was fit for the presidency. Hillary Clinton isn’t there yet, nor can she get there by blaming Donald Trump for failing to confront the alt-right when she is failing to confront the alt-left. The point is all the more vital because one of the hopes President Obama stirred in his 2008 campaign was for a chance that his unique embodiment of the black and white experience would enable him to lead us to a higher plane. In the event, the eight years of his presidency have seen the return of violent protests to our cities.