We’ve been getting the lowdown on Donald Trump for quite some time from the ultimate insider — a family member. Trump’s niece Mary, who is a psychologist on top of being someone with the last name Trump who isn’t an idiot, regularly weighs in on her uncle in various new outlets.

Now she says she knows what his next “trigger” is going to be, just knowing his nature.

Mary took one look at all the empty seats that have been appearing at his rallies and appearances and knew that Donald is about to have a meltdown.

“Donald isn’t going to like this. As he tries to grapple with Nikki Haley’s stronger-than-expected showing in New Hampshire, Donald’s campaign has a new problem: shrinking crowd sizes.”

Ms. Trump said that for some, that might not be that big a deal. But for Donald, it is everything.

The appearance of low attendance has always been a trigger for Donald, who infamously lied about the crowd size of his inauguration. If news of his crowd-size problem gets out, it will add to the increasing number of issues—like Nikki Haley’s stronger-than-expected showing, the increasing number of prominent politicians withholding their endorsements—having a negative impact on him.

The issue of crowd size may seem trivial, but not if you know Donald. Crowd size is one of the key ways Donald measures success. Small turnout, muted responses, and louder hecklers challenge him and stress him in a way few other things can. Huge crowds, and their violent energy, motivate him. They were a crutch. Without them, he loses an important method of deploying his message, and momentum.

Donald is vulnerable.

We shouldn’t ignore it when New Hampshire Republican voters say they voted for Haley in order to stop Donald. Perhaps they are disgusted with his party too. Just this evening, the House ethics committee announced it reached out to a woman who allegedly had sex with Matt Gaetz when she was just 17 years-old.”

Of course, that last bit is a story for another article. But Mary Trump knows what she’s talking about. The former president didn’t just lie about the crowd size at his inauguration — all the way back at the beginning of his presidency, but he dragged it on and on. He insists to this DAY that it was the largest inauguration crowd any president’s ever had.

Because he needs it to be. In his eyes, if you’re not first, you’re last.