Now, amid rumours that Kim is sick or even dead, current and former US officials and North Korea analysts say Trump’s mano-a-mano diplomacy looks shakier than ever because the Trump-Kim relationship has been the only one that truly mattered.

If a new leader emerges in North Korea, he (or she) may decide to grow the country’s nuclear arsenal as a way of consolidating and projecting power.

And with US-Chinese relations on a downward spiral due to fallout from the coronavirus pandemic, the idea of international cooperation to diplomatically pressure North Korea and maintain economic sanctions on the country seems remote.

Trump says he knows how North Korean leader Kim Jong-un is doing

“The serious level of diplomacy required to move the ball forward with the North Koreans isn’t possible with Trump at the helm,” said Suzanne DiMaggio, a senior fellow with the Carnegie Endowment for International Peace. “The US negotiating team has not been fully empowered and, as a result, there still isn’t a consistent, reliable communications channel in place.”

With North Korea, of course, certainty is a rare commodity.

The country is one of the most isolated and secretive in the world. The health of its dictator is a highly guarded topic, and US intelligence services have limited views into the government’s activities even in more normal times.

For instance, US officials were not certain of the death of Kim Jong-un’s father, Kim Jong-il, until the regime announced it two days later in December 2011.

With reliable information hard to come by, Korea analysts often resort to creative means to try to assess the truth. Over the weekend, for instance, researchers with the 38 North website, affiliated with the Stimson Cenrtr, reported that satellite imagery showed that a train thought to be Kim’s was parked in Wonsan, a port city he has sought to turn into a beach resort.

But Kim watchers differed on what it meant: did it indicate he was alive? Was it a clever ruse, meant to throw American spy agencies off the scent?

Kim has not been seen in public since April 11; his failure to appear April 15 during the commemoration of the birthday of his late grandfather, North Korea’s founding totalitarian ruler, surprised observers.

While he is believed to be 36 – young for a strongman – Kim smokes and is clearly obese. His health has been a topic of speculation ever since he took charge following his father’s death in 2011.

Satellite images show train at North Korean resort as Kim rumours swirl

US officials are not, for now, expressing serious concerns that Kim is dead. They do not, however, rule out that he is ill or recovering from medical treatment. Some point out that he has disappeared from view before, including for several weeks in 2014, when it was later reported that he had had to have ankle surgery.

“It’s a watch and wait situation,” a Trump administration official told POLITICO. “There’s a sense that there’s not enough information to change our posture.”

In an interview last week with conservative host Hugh Hewitt, Trump national security adviser Robert O’Brien said “it’s hard to know when you’ve got a country that’s as closed up as North Korea”, but insisted that the US is “keeping a close eye on things”.

And while Trump has declined to detail what he knows of Kim’s situation, he has said that a CNN report that Kim may be gravely ill was “fake.”

“I have a good relationship with Kim Jong-un, and I hope he’s OK,” Trump told reporters last week. He also insisted that the US “would have been in a war with North Korea if I didn’t get elected president”.

On Monday, North Korean state media reported that Kim had “sent his appreciation” to workers building a tourist zone in the Wonsan area.

Separately, a senior South Korean official told Fox News over the weekend that Seoul believes Kim “is alive and well” and has been staying in the Wonsan area since April 13. He added: “No suspicious movements have so far been detected.”

A person familiar with the situation told POLITICO that others in the region also have not detected unusual movements within the North Korean government, including among the military brass. There is no sense of panic yet, the person said.

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But among some current and former US officials who spoke to POLITICO, all on condition of anonymity because of the highly sensitive nature of the subject, the episode is a sign that the Trump administration needs to restructure its strategy toward Pyongyang to be more bottom-up than top-down.

“The idea that Trump can do it all alone has been shown to be complete nonsense,” said one former US official who is in regular touch with people inside the Trump administration.

Current and former US officials argue that Trump’s leader-first approach has meant that the North Korean government does not put stock in the entreaties and promises of lower-level people in the Trump administration.

For instance, Stephen Biegun, the US special representative for North Korea, early on struggled to establish communications with North Korean counterparts, people inside the administration say. (The North Korean government is so opaque that US officials are not always sure who to talk to at any given time.)

Biegun is now deputy secretary of state, but he retains the North Korea portfolio. While he has not yet brought home any major wins, the fact that the North Korean state media have not attacked him is a sign that he might be making some inroads, said Jung Pak, a former senior CIA analyst.

The problem is that “it’s all relative with North Korea”, said Pak, whose new book, Becoming Kim Jong Un, comes out this week. Ultimately, she said, “this is an empty calorie relationship where there’s nothing beneath whatever Trump says”.

Secretary of State Mike Pompeo has had less luck than Biegun. Pompeo visited North Korea multiple times as part of the administration’s effort to push forward talks, but the North Koreans have made their disdain for him clear.

They have used official statements to describe him as “gangster-like” and “ludicrous” and demanding he be removed from future talks. (North Korea had similarly unkind words for Trump former national security adviser John Bolton.)

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The former US official said many of the Trump administration appointees focusing on North Korea lack serious diplomatic experience in the region, and they are not coordinating well enough with American diplomats who deal with countries such as South Korea, Japan and China.

Working with those countries is crucial, especially if Kim is replaced as the head of the regime. But the US relationship with each of those states is frayed.

The Trump administration has made no secret of its view of China as a threat to the US in areas ranging from cybersecurity to trade. The two countries have in recent months engaged in a war of words over who is to blame for the spread of the coronavirus, which emerged in China’s Hubei province.

But China is North Korea’s most important economic partner, and often its shield at multilateral forums such as the United Nations. It is deeply wary of destabilising the regime in Pyongyang politically or economically, for fear it will have a massive humanitarian and refugee crisis on its borders.

For US or international sanctions on North Korea to work, China has to go along. Sometimes it does – such as in 2017, as Trump led a maximum pressure campaign against Pyongyang. But that Chinese commitment is rarely 100 per cent; Beijing has pushed Trump to relax sanctions in more recent years.

Japan and South Korea are historically close US allies that house American military bases, but both have felt bruised by Trump’s tariff-heavy actions on the trade front.

They have also felt insulted by his demands that they pay much more to cover the cost of keeping US troops in the region. At times, the two – especially Japan – have had to scramble to stay looped in on US-North Korea policy.

Trump’s investment in Kim could also complicate the dangerous period that accompanies a transition of power in a country ruled by fear and force.

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The US has developed past contingency plans for how to deal with a North Korean change in leadership, but they have been “premised on ongoing relationship, especially with the allies – clarity of what we want to do, and what they want to do, and similar clarity with China”, the former US official said.

Current and former officials, as well as outside analysts, do not underestimate the challenge any administration has in dealing with North Korea, and they do not all fault Trump for initially throwing out convention in sitting down with Kim.

The history of US diplomacy toward North Korea is rife with failure and frustration. Past sitting US presidents, Democratic and Republican alike, never met their North Korean counterparts, and yet struggled and ultimately failed to permanently dismantle North Korea’s nuclear arsenal.

Trump’s predecessor, Barack Obama, was accused of essentially giving up on the North Korea nuclear issue, even as he managed to strike a nuclear deal with Iran.

Kim’s father, Kim Jong-il and his grandfather, Kim Il-sung, did not make things easy for US envoys. Kim Il-sung died in July 1994 soon after meeting former US president Jimmy Carter and expressing a willingness to suspend his country’s nuclear programme and establish relations with the United States.

Kim Jong-il oversaw the initial implementation of that resulting 1994 arrangement called the Agreed Framework, but over time, that deal collapsed, with both sides casting blame on the other. Kim Jong-il died December 17, 2011; his passing caught the US intelligence community off guard, according to reports at the time.

By then, North Korea was suspected to have a still-small nuclear arsenal.

Before Trump, the general US blueprint for negotiations with Pyongyang – or any government, really – involved starting at lower levels. Diplomats from the State Department, for instance, would meet North Korean counterparts to hammer out basics, such as confidence-building measures, with the goal of eventually pushing the talks upwards.

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Trump, a political neophyte, campaigned for the presidency in part on his reputation as a deal maker from his real estate days. Obama warned him that North Korea may prove the top threat facing the United States, and Trump spent much of his first year trading insults and threats with Kim Jong-un.

He promised “fire and fury” if North Korea made any threatening moves and heaped economic sanctions on Kim’s regime. Kim called Trump a “dotard” and pressed ahead with missile tests and other nuclear-linked actions.

At the behest of South Korea, Trump eventually agreed to meet Kim. The pair first met in Singapore in June 2018, appearing friendly and signing a vague declaration promising to work toward denuclearisation.

They met again in Vietnam in February 2019, but ended the summit early when Trump said he could not agree to Kim’s proposal that he lift numerous US sanctions in exchange for modest curbs on North Korea’s nuclear programme.

The pair nonetheless met once more later that year at the demilitarised zone, the boundary that separates North and South Korea. Trump became the first sitting president to set foot on North Korean soil.

Trump also has repeatedly boasted of his warm personal ties with Kim, even saying the two “fell in love.” The pair also have exchanged letters.

There are signs, however, that even that relationship is cooling. After a lengthy moratorium amid talks with Trump, North Korea resumed testing missiles months ago. North Korea also swiftly denied a Trump claim earlier this month that he had recently received a note from Kim. The North Korean statement warned Trump not to use the relationship for “selfish purposes.”

There is, meanwhile, plenty of speculation in official and unofficial spheres as to who will succeed Kim if he dies or otherwise loses power. One contender appears to be Kim Jong-un’s younger sister, Kim Yo-jong.

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She is one of the few members of the Kim family who has an international profile, one aided by her attendance at the 2018 Winter Olympics in Pyeongchang in South Korea. She is believed to be in her early 30s and a relatively high-ranking North Korean politician.

According to US government statements, Kim Yo-jong is – or has been – the vice-director of the Workers’ Party of Korea Propaganda and Agitation Department, whose responsibilities include media censorship. Some Korea watchers have noted that Kim Yo-jong recently issued a statement in her own name, a possible sign of her growing clout.

But Kim Yo-jong’s ascendance is by no means assured. For one thing, North Korea’s government is dominated my older male generals who may not take kindly to obeying a young woman. There is also at least one uncle, Kim Pyong-il, who might prove a rival.

Whoever takes over in the event of Kim Jong-un’s death is highly unlikely to want to pursue nuclear negotiations with Washington immediately. They are more likely to look for ways to eliminate any immediate rivals and shore up their internal standing in North Korea – including adjusting the propaganda machine to herald and promote their rule.

“If Kim Jong-un passes away, there will be no real serious activity with the United States for a while – it may be years,” the former US official said. The new ruler will “really have to get their house in order. They have to feel confident they can come above ground.”