Sign up for the daily CJR newsletter . You’ve likely seen the video by now. At 8:34pm on Saturday night, the White House Correspondents’ Association (WHCA) dinner was getting underway. The US Marine Band had performed the national anthem. Salads had been served. Donald and Melania Trump were seated at the dais, between Karoline Leavitt, the press secretary, and Weijia Jiang, the president of the WHCA. Oz Pearlman, a mentalist and the night’s entertainment, was performing a trick for the group when there was a sudden commotion. The first lady reacted first, fear visible on her face. The camera quickly panned back as Secret Service agents rushed the stage. It was an alarming moment in an evening that would otherwise have been simply absurd, an almost perfect encapsulation of the whole affair. The scene was captured by Mohaimen Aljasheme , a C-SPAN photographer and veteran war cameraman from Iraq.…