Parscale is one of the few within Trump’s crew entrusted to tweet on his behalf. He’s sitting at a long table in a double-wide trailer behind the debate arena, cheek to jowl with his fellow Trump staffers and Reince Priebus, chairman of the Republican National Committee. The charged atmosphere and rows of technicians staring raptly at giant TVs and computer screens call to mind NASA on launch day. On the wall, a poster of Julian Assange reads: “Dear Hillary, I miss reading your classified emails.”