Analysis: Why 'deal-maker' Trump felt meeting with Kim was a bridge too far
If one thing is known about Donald Trump's approach to foreign policy, it is that he sees every issue as a zero-sum game negotiation.
From the Iran nuclear deal and China trade battle, to getting Mexican border wall funding and more Nato defence spending, the president has followed a similar pattern.
First he builds up the threat of something terrible happening, then forces the other side to the negotiating table in the hope of reaching a middle ground.
With North Korea, exactly that had been playing out. There were threats of "fire and fury", escalating military exercises in the region and a spiralling war of words with Kim Jong-un in 2017.
But when Mr Kim changed his tune in 2018, sending athletes to the South Korean Winter Olympics and holding talks with South Korea, Mr Trump jumped on what he wanted: to sit down at the negotiating table.
So what has changed? Why has the president pulled the plug on a June 12 summit in Singapore so historic that the US government already minted coins to celebrate?
The president's view of negotiations is you are either coming from a position of strength or weakness.
In the run-up to the summit, Mr Trump felt well-placed.
His tough rhetoric had brought Mr Kim to the negotiating table. He had tangible wins in the form of three US detainees being returned.
Mr Kim had begun showing the respect rhetorically that he demands from other world leaders and in turn the president had reciprocated, thanking the "excellent" North Korean leader for the US detainees' return.
But in the last fortnight that changed. Suddenly it has been the regime making the running - threatening to pull the talks and chastising America for its approach and demanding concessions.
The change in tone left Mr Trump appearing weakened, seeking to placate the North Korean regime in an attempt to keep the summit afloat.
The president tried at first. He undermined John Bolton, his national security adviser, by saying the Libya model - when Muammar Gaddafi abandoned his nuclear programme - would not be used for North Korea. He also offered Mr Kim "protections" if he did a deal.
But the tough rhetoric from Pyongyang continued, leaving Mr Trump to play a card familiar from his business career - walking away from the negotiating table.
Interestingly, in Mr Trump's letter announcing the cancellation he repeatedly keeps the door open to rearranging talks, telling Mr Kim: "If you change your mind having to do with this most important summit, please do not hesitate to call me or write."
North Korea had begun to indicate that it was unwilling to agree to Mr Trump's terms for talks.
The Trump administration's starting point to talks was that the North Koreans must agree to fully denuclearise - whatever the time frame and definition - before the US would act.
In other words, Mr Kim needed to act first and follow through on his warming rhetoric. Only then would America consider easing economic sanctions.
In recent statements, the North Koreans have rejected that starting point.
Last week Kim Kye Gwan, North Korea's first vice-minister of foreign affairs, said: "If the US is trying to drive us into a corner to force our unilateral nuclear abandonment, we will no longer be interested in such dialogue."
The North Koreans wanted a tit-for-tat approach, where steps towards denuclearisation were made alongside an easing of sanctions.
In the last week that has looked less and less likely.
Pyongyang's decision to target figures close to the president for criticism likely rankled for a president who prizes loyalty above all else.
Mr Bolton was singled out by North Korea last week in the first signs the regime was changing its stance on talks.
Mr Kim, the senior foreign affairs official, said the county's leaders viewed Mr Bolton with "repugnance" and criticised his adoption of the 'Libya model' for talks.
Then on Thursday, Mike Pence, the US vice president, was dubbed a "political dummy" who had expressed "impudent" views by another North Korean official.
The president said in an interview on the Wednesday before that there was a "good chance" the meeting would go ahead, suggesting those comments had an impact.
North Korean jibes at senior Trump administration officials could only be left unanswered for so long.
Finally, there is the domestic political pressure.
The first few months of 2018 have seen Mr Trump lauded by his right-wing supporters as North Korea appeared to come in from the cold.
Some floated the idea of Mr Trump winning the Nobel Peace Prize. The president humbly reacted by saying "everyone" thought he should get the award but that "victory for the world" would be much better.
What a difference a fortnight makes.
The return of North Korea hostility has got the left crowing again, portraying the president as a dunce who got fooled by Pyongyang.
"North Korea acts like North Korea" tweets were issued by foreign policy experts with a "we told you so" tone that may have got under the president's skin.
When Mr Kim threatened to scrap the summit, Mr Trump was criticised for believing North Korea's earlier warming in rhetoric and proclaiming that progress was being made.
Now the president has taken back the initiative by doing what he always threatened to do - walking away. (© Daily Telegraph, London)