The high point of Alex Jones’ public life—and the moment that it all began going inarguably downhill—happened in the small hours of the morning after Election Day 2016, not long after Donald Trump declared victory. “I already know my life’s purpose has been completed,” Jones said on air from behind the massive Infowars desk, his eyes watery and even more reddened than usual. “I will continue on. But for now, I realize, I have won.” In the years since, Jones has tumbled precipitously, a descent that is, ironically, all due to his increased fame. Jones’ relationship with the former president—as...