While the problem of anti-Semitism is not novel to the Trump era, Weisman argues, the president has not actively discouraged bigotry, blowing enough dog whistles and making enough excuses to leave far-right agitators feeling empowered. “Whether he knew it or not, Donald Trump ran the most anti-Semitic presidential campaign in modern American history,” Weisman writes. “Haplessness is not a defense.”