The trouble with so many of Ann Coulter's critics is they're conspicuously ill-informed. Take for instance, their attacks on the late Sen. Joe McCarthy, the legendary anti-Communist she champions in her current best seller, Treason. When Fox News's Bill O'Reilly said McCarthy "demonized people who didn't deserve to be demonized," Coulter shot back: "Name one." O'Reilly balked for a moment, then boldly proclaimed: "I'll name one. Dalton Trumbo." O'Reilly was breathtakingly mistaken. When Coulter countered McCarthy "had nothing to do with Trumbo," O'Reilly blithely compounded his error. "Sure, he did," he said, and then plowed ahead, "It was a House...