Tannen says psychologist Paul Ekman "set up experiments in which individuals were videotaped talking about their emotions, actions, or beliefs--some truthfully, some not. He has shown these videotapes to thousands of people, asking them to identify the liars. ... Most people performed not much better than chance, and those who did the worst had just as much confidence in their judgments as the few who were really able to detect lies." Tannen applies this finding to competitive debates, in which the contestants fight to win, leaving us to discern who's right. Since the risk of such debates is that the participants will lie, Tannen concludes that our willingness to "accept this risk" is based on the false premise that we can discern the lies. In short, she thinks such debates aren't worth the risk.

Even if Ekman's study used a random sample of liars--which is hard to believe, since bad liars are, by definition, easy to spot--it proves nothing about our ability to distinguish truth from falsehood in politics. In politics, we get to watch people speak on different occasions over time, often in response to questions from more than one interlocutor. So for example, you might deem Bill Clinton an honest man, based on a single video clip in Ekman's study. But in the real world, seeing Clinton face new challenges and field new questions over time, you might come to believe that he often lies.

Tannen's erroneous conclusion--that we can't discern lies in general--largely accounts for her authoritarian maternalism. The lie that most infuriates her is Holocaust denial. The American solution is to disseminate the truth, principally through the U.S. Holocaust Memorial Museum. The Canadian solution is a ban on ethnic hate speech. Tannen doesn't trust the American solution: She cites a New Zealander's dismissal of the Holocaust museum--"one-sided Jewish propaganda"--as evidence that the truth has no special power over lies. Even the Canadian speech law seems insufficiently strict for her: She complains that when a Holocaust denier was tried for violating that law, his lawyer was permitted to cross-examine Holocaust survivors about their experiences.