Trump’s online missives make his supporters laugh and even his opponents think past the sale.

As a trained hypnotist and a lifelong student of persuasion, I’m often impressed by how much “work” President Trump gets out of his tweets. Most of them are harmless retweets about whatever is going right, and they tend to be forgettable. The good ones are something entirely different, and many are gems of persuasion. Consider this one: “With Jemele Hill at the mike, it is no wonder ESPN ratings have ‘tanked,’ in fact, tanked so badly it is the talk of the industry!” When Mr. Trump smack-tweets a notable public critic—Ms. Hill has called the president a “white supremacist”—it violates our expectations of his office. That’s what makes it both entertaining and memorable. He often injects into his tweets what memory expert Carmen Simon calls a “little bit of wrongness” to make it hard to look away. If the wrongness alarms you, consider that for years he has adroitly operated within a narrow range of useful wrongness on Twitter without going too far. That suggests technique. In the Twitter environment, strategic wrongness is jet fuel.

Watch for Mr. Trump’s tweets to make you think past the sale, a well-known technique of persuasion. In the Jemele Hill tweet ...

Here’s another example in which the president makes you think past the sale: “People are just now starting to find out how dishonest and disgusting (FakeNews) @NBCNews is. Viewers beware. May be worse than even @CNN!” If you find yourself wondering which is worse, NBC or CNN, you are thinking past the sale that both are bad. I also see the president as employing a modern version of humor. When he goes after one of his high-profile critics, his supporters laugh and reach for the popcorn. This is gonna be good! Voters who preferred Hillary Clinton are not laughing, of course. But they aren’t the audience for his tweet humor. And that makes it even funnier for his supporters. His base is in on the joke, whereas his detractors don’t even know humor is happening.

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