A chastened Donald Trump came out last night to celebrate his victories in yesterday’s primaries, speaking at one of his country clubs, perhaps to illustrate the breadth of his appeal to voters. He read the speech from a teleprompter, one of the few times he has done so during this campaign. It sounded like a mixture of Trump’s own sentiments (“Recent polls have shown that I’m beating Hillary Clinton”) and things someone else wrote for him (“This is not a testament to me, but a testament to all of the people who believed in real change”).

But what we didn’t hear was another round of shots at Gonzalo Curiel, the judge presiding over the Trump University fraud case. For now, anyway, Trump seems to have finally been prevailed upon to shut his mouth on that subject.

What did that bizarre episode show us about who Trump is and what the implications are for the rest of the campaign? A number of things:

  • Trump can’t resist using his campaign as a vehicle to fight his personal battles. This case seems to have gotten Trump more worked up than almost anything else that has happened during the campaign. But instead of fighting the lawsuit in the most strategically advantageous way — through his lawyers — he went on a series of rants at rallies, often to the puzzlement of the crowd, about how supposedly unfair the judge was being to him. It wouldn’t do anything to help him win the case, and it wouldn’t win any more voters to his side, no matter how persuasive he had been on the subject of the judge’s alleged bias. But he had an audience, so he just had to lash out to them. This will probably not be the last time Trump gets embroiled in a personal conflict that he brings into the campaign, causing his own allies to ask, “Why the hell is he talking about this?”
  • Trump can’t resist making bigoted attacks. Not only is there no reason to believe Judge Curiel is biased against Trump (many of his rulings in the case have gone in Trump’s favor), there’s absolutely no reason to believe that he’s biased against Trump because of his ethnicity. But Trump sees a Latino judge who isn’t bowing down before him, and immediately assumes it must be because the judge is “Mexican.” It’s not persuasive, and it’s almost certainly going to lose him some of the few remaining votes he has among Latinos. No sane person would ever have advised Trump to go there. But he just couldn’t help himself.
  • Trump’s spectacularly thin skin will continue to be a liability. We’ve seen this again and again: Trump can’t tolerate even the mildest criticism. If you’re not on his side you’re an enemy, and enemies have to be attacked in the most vicious and public way possible. There’s no doubt that this is a core part of Trump’s personality, one even he will admit to. But when you’re consumed with slights, not only do you wind up looking petty and mean, you also cede the agenda to your opponents. If all they have to do is criticize you to knock you off your game and get you talking about whatever they want you to talk about, they’re the ones determining the path the campaign takes.
  • Trump’s greatest fear is being exposed as a penny-ante grifter. As Trump will proudly (for some reason) tell you, he’s involved in hundreds of lawsuits, as both a plaintiff and a defendant. Why is the Trump University one so important? Because it shows Trump to be not a captain of industry but a small-time con man. He’s putting his name on a scheme to get desperate people to come to hotel conference rooms and max out their credit cards, for a few hundred dollars here and a few thousand dollars there. According to New York Attorney General Eric Schneiderman, Trump’s entire profit on Trump University was $5 million, which for a guy who claims to be worth $10 billion ought to be pocket change. So why does he do it? Why would a guy who’s  supposedly so rich be so desperate to grab such small sums, trying to hock steaks and vodka and water? Why start a pyramid scheme selling vitamins? Trump’s entire brand is built on the idea of his enormous wealth and success. If everyone concludes that he’s just a low-rent con artist, then the entire edifice crumbles — both the business and the candidacy.
  • Trump has no sense of what’s harming him politically. Throughout this campaign, Trump has seemed to many like a political idiot savant, confounding the expectations and advice of all the experts. But this episode demonstrates that he often has no idea when he’s doing himself political damage. As Bloomberg News reported, Trump overruled his campaign staff to tell his surrogates to go out and join his attacks on Judge Curiel and on the journalists covering the story. “I’ve always won and I’m going to continue to win,” he said in response to the idea that this was a bad idea. “And that’s the way it is.”
  • Trump can be brought to heel by Republicans, but it takes an awful lot do it. At last, Trump was finally persuaded to drop the attacks on Curiel — or as Mitch McConnell put it, “it’s time to quit attacking various people you competed with or various minority groups in the country and get on message.” But look what it took to persuade him: Condemnations from McConnell and Paul Ryan, the two congressional leaders of his party. A couple of dozen other Republican elected officials blasting him for it, with some even proclaiming they won’t vote for him. Pretty much every conservative pundit expressing their horror and dismay. In other words, it wasn’t until practically the entire Republican Party came out and publicly told Trump that he was digging his own grave that he finally considered that they might have a point.

There are always people within a presidential candidate’s party who think he or she is screwing up. When it’s expressed, it usually takes the form of anonymous quotes whose real message is, “If only the candidate were listening to me, he’d be doing so much better.” But they seldom say so publicly and with their names attached, which is what made this case so extraordinary. And I’m guessing it won’t be the last time Trump does or says something so plainly foolhardy that the party once again has to mobilize itself as one to convince him to change course.

As we saw, it can be done. But it’s not easy, and by the time Republicans accomplish it, a great of damage will already have occurred.