Opinion: Something is rotten in Trump’s Greenland spat, but it’s not in Denmark

It’s easy — too easy — to regard President Trump’s unexpected feud with Denmark as comic relief from more troubling manifestations of his often capricious and self-obsessed approach to foreign policy.

On Tuesday, Trump took to Twitter to say that he was postponing a planned visit to Denmark because Prime Minister Mette Frederiksen had rejected his improbable idea of a possible U.S. purchase of Greenland. Frederiksen said talking about a sale would be “an absurd discussion.”

Trump, who can dish criticism out but can’t take it, yanked his R.S.V.P. His tweet ended with this bit of junior-high-school-level sarcasm: “The Prime Minister was able to save a great deal of expense and effort for both the United States and Denmark by being so direct. I thank her for that and look forward to rescheduling sometime in the future!”

On Wednesday, Trump doubled down, calling Frederiksen’s rejection of the idea of a sale “nasty,” an adjective he famously applied to Hillary Clinton. He suggested unpersuasively that in calling the Greenland idea absurd, the prime minister was insulting not him, but the American people.

Trump’s overreaction is ridiculous and, yes, funny. And because Denmark is a U.S. ally that is unlikely to retaliate for the president’s snub, it’s easy for Americans to yuck it up about the president thinking something is rotten in the state of Denmark, or about how Danish pastries will now be renamed “freedom pastries.”

Still, this latest Trump tantrum offers a window on how the president might handle — and has handled — foreign negotiations with more serious implications.

The idea of this country buying Greenland was bonkers, but people in this country and abroad long ago accustomed themselves to Trump talking nonsense about everything from windmills to vaccinations to supposed voter fraud. But his decision to cancel his trip because of the Danish government’s perfectly predictable reaction to his potential business proposition was more than a harmless gaffe.

Trump has snubbed not only Denmark’s prime minister, but the country’s head of state, Queen Margrethe II, who would have been his official host.

Finally, the personal flaws highlighted by this episode could undermine U.S. interests in more serious situations. The hypersensitivity to criticism Trump displayed in canceling his trip is the flip side of the susceptibility to flattery that has led him repeatedly to give the benefit of the doubt to North Korea’s Kim Jong Un, who was shrewd enough to send Trump “beautiful letters.”

So enjoy the “Hamlet” and pastry jokes. But remember that the next whimsical foreign policy decision by this president might not be a laughing matter.