“I guess the question is, when can we trust the president when he says something is phony and when he says it’s real?” wondered NBC’s Peter Alexander. Spicer said Trump can be trusted. “How can we believe that [the employment report] is real when you just told us that it was phony then, but now it’s real?” Alexander replied.

After skirmishing for a few minutes, Spicer concluded that the press, and the people, should take the president’s statements seriously—“if he’s not joking, of course.”

This is a nifty piece of rhetoric. How is anyone to know whether Trump is joking? As Philip Bump noted after Monday’s exchange, that’s very difficult to tell. Trump doesn’t really tell jokes in any sort of traditional sense. At the Al Smith Dinner in October, during which candidates typically offer good-natured ribbing of each other, Hillary Clinton delivered a fairly standard spiel. Trump, by contrast, drew boos and stunned silence for his routine, which wasn’t really a series of jokes so much as a series of insults.

Trump has tried to claim inflammatory claims were just jokes before. In August, he called Barack Obama the “founder” of ISIS. It was a weird sort of claim, in that Trump almost certainly didn’t literally mean that Obama had founded ISIS (although given Trump’s tendency to pal around with Alex Jones, one can never be too sure). Instead, he seemed to mean that Obama’s policies had fostered ISIS. A debatable assertion, to be sure, but not an insane one. Yet the following day he went on Hugh Hewitt’s radio show and insisted, “No, I meant he’s the founder of ISIS. I do.” Finally, later, he claimed he had been “sarcastic” all along. That’s not how sarcasm works, and the claim didn’t make sense given his comments on Hewitt’s show. Trump also pleaded sarcasm after getting up at a press conference and encouraging Russia to hack Hillary Clinton’s State Department emails.

This is a maneuver familiar to anyone who attended junior high school: When you screw up, just claim you were kidding and that everyone else missed the joke.

Even if you were to take Trump’s claim that he was joking seriously (so to speak), it would be nearly impossible to tell when he is and when he isn’t, since he speaks with an unusually consistent tone and because, as my colleague Alex Wagner and Chuck Todd have observed, Trump almost never really laughs.

If you have a joke, however, there must be a butt for that joke. And in these cases, it is typically the press. In Act I, Conway made her “microwave” remarks, which every context clue would suggest were simply a silly gaffe, weird flight of fancy (based, perhaps, on WikiLeaks dump of CIA documents last week). In Act II, reporters, correctly sizing Conway’s comments up as ridiculous but overplaying their significance, spent the next 24 hours or so reporting, analyzing, aggregating, and fact-checking them. In Act III, Sean Spicer wrote the whole thing off as just a big joke—thus making the media look immensely silly for having chased after a shiny bauble for a day.