One of the most quoted clichés among North Korean experts is that Kim Jong-un is really smart, that he knows what he’s doing, all so shrewdly calculated for maximum effect.

Just who qualifies as a North Korean expert and who doesn’t is another matter. In a sense we’re all experts. We all have opinions about North Korea, and much of what we say, write and think is unprovable, so who’s to know who knows anything?

Which brings up the question: How shrewd and diabolically smart was it for the North Koreans to blow up a sparkling, newly remodeled building in the Gaeseong Industrial Complex? We get why they did it.

The South Koreans had renovated the building so it would be great as a place for North and South Koreans to get together, sip coffee, or maybe soju, and talk over their issues and problems like old friends.

So blowing up the building was a great way for the North to tell the South Koreans to… well, at this stage the only words would be unprintable, but you get the idea. How better to show off your rage, your frustration, your superiority, to denounce and pillory your opponents than by blowing up a building right in their faces?

Actually, a lot of us would like to do just that in a fit of petulance, but mostly we don’t get the opportunity.

But here’s where I have to wonder how smart it was for Kim Jong-un, or maybe younger sister Kim Yo-jong, to come up with the idea of blasting the building, leaving a pillar of smoke visible for miles around.

What did they actually get from this gesture aside from the thrill of being able to curse and gnash their teeth at the South Koreans and leader Moon Jae-in, who has gone through three summits with Kim thinking he’ll make history as the one who achieved North-South reconciliation?

Here’s the thing. Although this building was Moon’s baby, his brainchild, the physical embodiment and symbol of his dream, it was also pretty good real estate. Since it was safely on the North Korean side of the demilitarized zone, it belonged to North Korea.

Practically speaking, would not the Kim-and-Kim brother and sister duo, have been a little smarter if they’d decided to tell Moon, “Get out. We’re not using this great edifice as a useless liaison office, it’s ours and we’ll do whatever with it.”

For sure, Moon could have done nothing if Kim/Kim had wanted, say, to turn the building into the headquarters of the Gaeseong branch of the Workers’ Party, or maybe into a police station or military headquarters. There are so many ways the North Koreans could have used the structure, taunting the South Koreans all the while, telling them, don’t infringe on our sacred land and don’t go telling us what to do.

Instead, their way to stick it to the South has inspired more laughs than tears. After all, what use would the building have been to anyone in Seoul considering the South Koreans could never get up there, across the DMZ, without North Korean consent?

But maybe Kim and Kim were not so dumb after all. They did manage to get a few headlines, images on television screens otherwise filled with shots of protests in the U.S. and United Kingdom. How better to capture the world’s fleeting attention, at least for a few seconds, without physically harming anyone or firing a shot?

The effect was so startlingly great as a break in the TV news that you’ve got to think America’s No. 1 gawker, President Trump himself, would have seen it. You have to wonder, what was Trump thinking?

Did he ask himself why his old pal Kim Jong-un would do such a thing? Did he feel a little disappointed that all the claims, the dreams and fantasies engendered at his summit with Kim in Singapore two years ago were going up in smoke?

Or might Trump be thinking, if only we make a few more concessions maybe my friend Kim will give up his nukes and missiles, even open up his kingdom to routine visits, mail, commerce, all that normal stuff?

You have to hope neither the American nor the South Korean presidents will be so stupid as to fall yet again for that man’s nonsense.