By cancelling his state visit to Denmark, the US president has again showed his thin skin

Donald Trump’s abrupt decision to cancel his state visit to Denmark after it rejected his unsolicited offer to buy Greenland at a knockdown price took most people by surprise, not least his own ambassador.

“Denmark is ready … Partner, ally, friend”, tweeted Carla Sands, the neophyte US envoy to Copenhagen who was previously an actor and chiropractor. Hours later, it was off.

The embarrassment of Sands, a loyal Trump campaign fundraiser best known until now for her starring role in the 1988 film Deathstalker and the Warriors from Hell, elicited scant sympathy from Danes apparently relieved the US president was not coming.

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“Hahaha, well maybe your boss should update you about what is going on in his mind. This proves how crazy this administration is,” one Twitter user wrote. Some American respondents apologised for their president’s behaviour.

Greenland’s unsought role in this new Nordic saga, wacky even by Trump’s eccentric standards, has again raised questions about his mental state and a chaotic decision-making process in Washington that often leaves partners and allies out in the cold.

Trump recently secretly ordered military strikes on Iran, then called them off with 10 minutes to go. He caused more Scandinavian amazement and amusement last month when he sent a hostage negotiator to Sweden after the American rapper A$AP Rocky was arrested for common assault.

Anthony Scaramucci, a former communications director for Trump, told the BBC the much-pummelled president was like a punch-drunk boxer still standing in the 12th round with no real idea what he was doing. His handlers should throw in the towel, Scaramucci suggested.

That may be an overly kind explanation. The Greenland episode has also highlighted Trump’s personal rudeness and undiplomatic willingness to offend close US allies. The visit next month was at the invitation of Queen Margrethe II, who, unlike Prince Hamlet, was apparently prepared to tolerate something rotten in the state of Denmark, at least for a couple of days. She will not be amused.

Mette Frederiksen, the Danish prime minister, was glacially cool towards the idea of selling Greenland to Trump. She described the US, which maintains a military base in Qaanaaq, also known as Thule, in north-west Greenland, as a valued strategic and Nato partner. But she poured cold water on the purchase, suggesting it smacked of disrespectful neocolonial attitudes.

“Thankfully, the time where you buy and sell other countries and populations is over. Let’s leave it there,” Frederiksen said during a trip to Greenland, a semi-autonomous Danish territory. The attempt to buy it was “absurd”. It is this blunt response that seems to have provoked the thin-skinned Trump to put his trip on ice.

The idea of such deals is not new, though dated. An expansionist US, pursing what was once called its “manifest destiny”, often bought or seized territory in the past. In 1803, it paid Napoleon $15m for a huge area of land ranging from what is now Canada to the south-eastern US, a deal known as the Louisiana purchase.

In 1848, the US relieved Mexico of about half its national territory, including most of what is now California, Nevada, Utah, Arizona, Colorado, New Mexico and Wyoming. In 1867, it bought Alaska from the Russians. In 1898, it took possession of the Philippines, Guam and Puerto Rico after fighting a war with Spain. The US once harboured designs on Cuba and Panama.

But Greenland residents plainly do not want to follow the US Virgin Islands, sold by Denmark in 1917. They have reportedly dismissed Trump’s offer, calling it patronising and unwelcome. Yet the fact the idea was even raised may serve to reinforce longstanding resentment, mostly directed at Copenhagen, that Greenlanders are treated as second-class citizens.

Political tensions have fuelled calls for independence among residents of the vast, sparsely populated island where about 57,000 people occupy 836,000 sq miles. Despite its largely untapped mineral wealth, which is what is said to most interest Trump, it is heavily dependent on more than £400m in annual subsidies from Denmark.

In common with other Arctic territories, Greenland has a recent history of social problems, including high rates of alcoholism, drug abuse and suicide among the indigenous Inuit people. Increased tourism has proved a mixed blessing.

Greenland is also disproportionately affected by the climate crisis and global heating. According to a CNN report from Kulusuk this week, scientists say 12.5bn tonnes of ice melted on one day this month – the biggest single-day loss ever recorded. That’s no joke – and it is a problem Trump stubbornly refuses to address.