The deployment of federal agents and National Guard troops has caused some Black parents to return to the days of “the talk” about policing that they had hoped was no longer needed to keep their children safe.Days after President Trump ordered a surge of federal law enforcement agents in Washington, D.C., Charlene Golphin told her 17-year-old son that his curfew was being cut short by two hours. Ms. Golphin feared that as a Black boy, her son would be caught in the dragnet set up by officers tasked by the president with cracking down on the “roving mobs of wild...