Across Washington last week, feverish gossip and innuendo swirled around Donald Trump’s close relationship with a young White House aide. But the president’s heart was bent on rekindling a love affair from his first term in office.

Kim Jong-un has always treated me with great respect,” Trump said of the North Korean tyrant. “I understand him. He understands me.”

In an attempt to recapture the magic of his last meeting with the nuclear-armed despot in 2019, Trump did not hesitate to throw a key ally under the bus. Posting on social media, where so much US foreign policy is conducted these days, the president announced that he had ordered the Pentagon to “substantially reduce” military exercises with South Korea.

Unconcerned by the acceleration of North Korea’s nuclear weapons programme or its military alliances with Russia and Iran, Trump declared that the war games – which have underpinned US military posture on the Korean peninsula since the 1950s – “send a signal that is totally inappropriate and hostile” towards Kim. The president has said he “fell in love” with the North Korean dictator during his first term.

In a manoeuvre that is now familiar to weary allies, Trump turned on Seoul, blaming his decision on South Korea’s refusal to join the war against Iran.

“We have 39,000 soldiers over there, guarding you from Kim Jong-un… and you’re not going to help us on a very easy military operation in Iran? That’s strange,” he told reporters at the White House.

He returned to a refrain that has epitomised his second term: “We can’t go around and protect all of these countries, especially when they’re not there to help us.”

Still trapped between military escalation and a humiliating climbdown with Iran, Trump continues to lash out at old friends he now blames for the quagmire in the Middle East.

South Korea was not the only ally to fall victim to Trump’s frustrated, upside-down diplomacy last week.

Oman, a key intermediary with Iran for years, is still endeavouring to break the deadlock and reopen the Strait of Hormuz, and has quietly opened a shipping corridor to move oil out of the Gulf. Its reward was a threat from an impatient president that he would “bomb the shit out of them” if Oman “gets in the way” of a deal to end the war.

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One security source in Washington said that Omani diplomats were “livid” at Trump’s latest broadside. “Because they feel they’re busting their ass off and all they get is negative commentary from the president.”

US allies the world over will sympathise. Trump’s bullying disdain for his country’s friends and eager embrace of its adversaries is now an established feature, not a bug of relations with this White House.

“Trump doesn’t like alliances… He doesn’t see the need for them,” said Daniel Fried, a former US ambassador and a senior director at the National Security Council under Bill Clinton and George W Bush.

“Trump has always had a frisson of attraction to dictators. He thinks diplomacy is really an issue of strongmen doing deals and carving up territory between them. And he’s being played.”

Trump’s relentless brinkmanship had already sparked fears among vulnerable allies over whether the US would back them in their hour of need. But the disastrous Iran campaign, which has drained American munitions stocks, now raises the question of whether the US is even capable of stepping up to support its friends in the next war.

Some are suffering mortal consequences. Days after Ukraine reported that July was the deadliest month for civilian casualties since the first weeks of the Russian invasion in 2022, Trump walked back his recent promise to allow Kyiv to build Patriot interceptor missiles under licence.

With Ukraine virtually defenceless from Russian missile attacks, Volodymyr Zelensky has begged for any Patriots the US can spare. But after draining two-thirds of its Patriot stocks in the Middle East, the Pentagon has none to give.

“We want missiles too,” the president said bluntly this month when asked about Ukraine’s plight.

Allies that have bent to accommodate Trump are now breaking.

“America has changed… we will not return to our old relationship,” the Canadian prime minister, Mark Carney, declared as he walked away from trade talks with the US on Friday and vowed to match Trump’s tariffs “dollar for dollar”.

Attitudes in Europe have also hardened after 18 months of insults and intimidation by the White House. A questionnaire from the Pentagon issued to Nato allies last week, which asked pointedly whether they had been “publicly supportive of US foreign policy priorities”, was just the latest affront.

A Pew Research Center survey last month of 36 countries – from western democracies to the global south – found that China was now viewed more positively than the US in nearly every one, often for the first time.

“China emerges in very good shape out of this,” lamented Fried. “What kills me is that Trump has won that argument with Nato and with South Korea, and he seems incapable of taking the win. There is something destructive about this administration… We are letting our strength leak away for no good reason.”

Photograph by Saul Loeb/AFP/Getty Images