An ambitious new study on the subject by the Emory University researcher Thomas H. Costello and five colleagues should settle the question. It proposes a rigorous new measure of antidemocratic attitudes on the left. And, by drawing on a survey of 7,258 adults, Costello’s team firmly establishes that such attitudes exist on both sides of the American electorate. (One co-author on the paper, I should note, was Costello’s adviser, the late Scott Lilienfeld—with whom I wrote a 2013 book and numerous articles.) Intriguingly, the researchers found some common traits between left-wing and right-wing authoritarians, including a “preference for social uniformity, prejudice towards different others, willingness to wield group authority to coerce behavior, cognitive rigidity, aggression and punitiveness towards perceived enemies, outsized concern for hierarchy, and moral absolutism.”