Trump speaks at a campaign rally in Prescott Valley, Arizona, on October 4, 2016. I f Donald Trump’s schedule holds, the latest chapter in the detestable saga of his presidency opens next week in Phoenix, where Trump is set to speak at a rally of his faithful, deranged followers. Despite public outrage, negative headlines, and many Republicans in Congress ever so faintly humming kumbaya, the president of the United States continues to revel in a perverse sort of post-Charlottesville euphoria that only he and his white-supremacist and neo-Nazi brethren can experience. As the president gleefully blabs and tweets his way to civil discord, Phoenix braces for the worst. Arizona’s two senators, Republicans John McCain and Jeff Flake, have excoriated him, while Greg Stanton, the city’s Democratic mayor, has asked him to stay away, to no avail so far. So the Tuesday rally could rip open angry wounds in a city still smarting from the excesses that S.B. 1070, the state’s harsh immigration law,...