Photo by Michael Vadon, licensed under the Creative Commons Attribution-Share Alike 4.0 International license.

Dear Dr. Boli: What does it mean for American politics that Donald Trump is the leading Republican candidate in the polls? —Sincerely, Reince Priebus.

Dear Sir: It means that poll-takers, who are as indolent as any of the rest of us, have been polling third-graders at recess. Third-graders are usually willing to answer questions, especially if you tell them it counts on their permanent record; and who can blame harried pollsters if they prefer not to chase down unwilling and potentially hostile adult subjects in the public street?

In debating his opponents, Mr. Trump uses a particular style of argument that is enormously effective on the third-grade demographic:

OPPONENT. I believe you are mistaken in your inference.

TRUMP. You’re ugly.

OPPONENT. What I mean is that there is overwhelming scientific evidence to support my assertion that vaccines do not cause autism.

TRUMP. I mean, seriously, who puts a face like that on network TV?

Because it is not usually encountered outside the playground, this rhetorical figure does not have a common name. Dr. Boli will therefore give it one, and call it the argumentum ad vultum, the argument against the face or countenance. It may be fallacious, but it is in its own way unanswerable. Even fashion models and movie stars who are paid to be attractive are generally convinced, in their secret hearts, that they are hideously ugly. Third-graders admire this argument because they know that it instantly brings debate to an end with a resounding victory.

Unfortunately for Mr. Trump, success in the public-opinion surveys may not translate very easily into success in the primaries. The number of registered Republicans who are old enough to vote but stupid enough to be still repeating third grade is very, very small. Furthermore, by bringing the argumentum ad vultum into the arsenal of modern political debate, Mr. Trump runs the very real risk that someone may eventually decide to employ it against him.