 Oh, no, not again, she says. I got that feeling you get of chaos and horror and no one in charge, that terrible cratering feeling you've had before. I was watching it live on television as I readied to go to dinner. Donald Trump was in a red MAGA hat talking about the border. I turned away for a moment. Then I heard a scream and looked back at the screen. The podium was empty. Mr. Trump seemed beneath it with Secret Service agents running toward him and surrounding him.