Monday was up there with the weirdest days in the Donald Trump campaign saga. Trump fired campaign manager Corey Lewandowski four weeks before the Republican presidential convention. Lewandowski went on CNN to give a post-firing interview, which was odd enough. But even more peculiar, Lewandowski appeared to be in an cultlike trance, praising his former employer and assuring the audience that things could not be better.

Putting Stepford wives to shame, Lewandoswki sounded like Trump himself explaining, “Mr. Trump has unparalleled success in the business world. He’s now unparalleled success in the world of politics. And I think when he presents an idea, some ideas are very, very good and they should move forward.” His relationship with the family was great. His relationship with nemesis Paul Manafort was great. They are winning in the state polls! (Not really, but he was on a roll.) Money is pouring in! The interview did seem to leave Dana Bash a bit incredulous. (“Corey, you’re painting a very nice picture of the Trump campaign and the state of play. If it was that way, why wouldn’t you still be the campaign manager?”)

And then another senior Trump adviser was forced to resign after tweeting in response to the Lewandowski firing: “Ding Dong the witch is dead!”

What may be most disturbing to GOP onlookers is that all of this is now entirely “normal” in the Trump campaign circus. Drama and bizarre behavior are constants. The presidential “pivot” is always just around the corner. And at the center of the storm is an abjectly unprepared candidate in over his head and careering from one crisis to the next. His hires are supplicants who have little ability or desire to steer him away from danger. His decision-making is emotionally driven and unpredictable.

Trump’s arrogance and narcissism prevent him from seeing himself or the world as others do, and push him to the brink of disaster. Not unlike with casino failings  — remember, he relented to strict controls on his spending only when the alternative was financial ruin — he now seems incapable of behavior modification unless the alternative is unbearable. In this case, according to reports, his own daughter threatened to stop helping on the campaign unless he canned Lewandowski.

There are two conclusions one can draw from this (other than that Ivanka would be a better candidate).

First, few people not employed or related to Trump will deny he is entirely unfit temperamentally and intellectually to be president. (Will his entire Cabinet have to quit before he, say, gives up the idea of Mexico paying for the wall? Will he deny evidence of Vladimir Putin’s next invasion?)

Second, the latest sequence of events suggests that when forced into a corner, Trump will crack. For all his bluster and bullying, his ego is as frail as it is enormous. His incapacity to admit error is such that he would rather make bizarre decisions and create unbelievable rationalizations than let on that he is not the genius and business success he says he is.

And yes, that is where the convention delegates come in. They have the upper hand. They have the power to force him to make a decision: give up his tax returns, letting us see whatever he cannot bear to be revealed, or give up the nomination. The tax returns might reveal his claims of wealth and generosity to be phony, or his business connections exceptionally shady. Would he consent to giving that up, to letting the country see that the emperor of real estate has no clothes? Or would he slink away, railing that the nomination had been stolen and bragging that he made a mint running for president? It is worth finding out.

Sheriff Joe Arpaio accused Republicans on June 18 of giving Donald Trump halfhearted endorsements. Is he right? (Peter Stevenson/The Washington Post)