Melania has learned a few things from the master. The first lady will never be as brilliant at trolling as her husband. He is an idiot-savant who plays in the roiling ocean of Twitter as naturally as a blubbery-necked sea lion. Only Donald Trump, a Rat Pack relic who spurred the reckoning with his transgressions toward women, could send out a tweet taking credit for the women’s march. But the Slovenian Sphinx has her moments. It started when she seemed to sartorially upbraid Trump for his Billy Bush vulgarities by wearing a pussy-bow blouse to the St. Louis debate. Then,...