Yet outside those circles, Bridges’s answers don’t really sound so convincing. In most of America, “Does a late-term fetus have value?” is a softball. And when Hawley leaped in to ask whether women are the ones who give birth — a question few Americans today would struggle with — she resorted to extended question-begging. That might be fine for a Berkeley classroom. But it just won’t do for a political debate in which the majority of voters disagree with you.

Anyone who has ever tried to convince anyone of anything should be able to see that Bridges’s approach was counterproductive. Why, then, did so many articles and tweets cheer the way she “SHUT DOWN” Hawley?

Because there is one place that snickering, eye-rolling and so forth are very effective: within an insular group, where they help delineate the lines of acceptable belief. A sufficiently incredulous “Are you suggesting … ?” effectively signals a silent corollary: “… because if you are, we’ll shun you.” It tells people that this topic is not up for discussion.

Within progressive institutions, “that’s transphobic” is another such signal, and it works … within progressive institutions. In fact, it works too well; it leaves them unprepared to argue with outsiders.