"The Red Hen Restaurant should focus more on cleaning its filthy canopies, doors and windows (badly needs a paint job) rather than refusing to serve a fine person like Sarah Huckabee Sanders," tweeted Donald Trump , who, relatedly, is the President of the United States. "I always had a rule, if a restaurant is dirty on the outside, it is dirty on the inside!"

So. Totally. Staggering.

There are those who would urge us to look away from this Trump tweet -- and the broader story of Sanders' expulsion from the Red Hen -- because it distracts from the family separation crisis at the border. And that's just what Trump wants! That's why he's sending this tweet!

I disagree. First, this is an official statement from the President of the United States. As outlandish and ridiculous as it is, it's still an official White House statement. Second, it's been proven over and over again that Trump's Twitter feed is the best window into what the most powerful person in the country is thinking about -- and cares about -- in a given moment in time.

That means you don't get to ignore these tweets.

(Sidebar: I don't buy into this 3-dimensional chess theory of Trump -- that every move he makes is somehow calculated as part of a broad effort to advance some sort of plan only he can see. As I've written before, I think there is far more evidence that Trump is playing 0-dimensional chess than he is the 3-dimensional kind.)

So, yes, this reads like a disgruntled Yelp review. ("The food was terrible -- and such small portions!") But that's exactly the point! The President of the United States is running down a tiny restaurant in a college town! Someone who is currently trying to see his way through a self-created crisis on the border. Someone who is trying to make good on a handshake agreement regarding the denuclearization of the Korean Peninsula. And someone, speaking of nukes, who has control of the entire US nuclear arsenal.

And yet, at 7:41 a.m. ET on Monday, what Trump was thinking about was that a restaurant kicked out his press secretary. And his chosen method of retaliation was a negative attack on the quality of the restaurant, which, coincidentally, will now be booked from here to eternity by liberals as a way of saying "thank you" for standing up to Trump and his administration.

That Trump felt the need to respond at all is a window into his psyche: He is someone who has never been able to let a slight go. Write a negative review of one of his hotels? Or of "The Apprentice"? Or of his presidential campaign? You are part of the cadre of "haters" and "losers" who are forever trying to deny Trump the praise and fame he believes is his right. And because he is Trump, he might just call you up or, more likely, tweet at you to express his displeasure.

Trump is now and always has been a low-road guy. Because he takes every negative comment as a personal slight, he feels the need to respond to every Tom, Dick and Harry who critiques him. And to do so -- as he did with the Red Hen -- in tremendously personal ways.

There's an old saying in politics (and life): Don't punch down. As in, there is no reason, if you are the President, to attack someone who owns a small restaurant in Lexington, Virginia, because, no matter what you say about them, you elevate them to your level -- and they win. (That same "don't punch down" advice is what the PR folks tell me when I want to respond to a nasty tweet directed at me. I, usually, listen.)

That's never been Trump's way. He thinks that when you get punched, you always, always, always punch back. It doesn't matter who does the punching. What matters is that you punch back -- and, in so doing, make clear you aren't going to just let people (any people) just punch you for free.

What that approach to life yields is a smallness with which we are not accustomed in our presidents. That smallness -- no slight too small to respond to! -- is yet another way in which Trump differs from the 43 people who have held the office of president before him. Those men saw the low road and usually tried to stay off it. Trump sees only the low road and proudly marches on it.