When it comes to finding a solution to North Korea, everybody seems to be talking to everybody else – except South Korea. While the United States, China, Russia and Japan deliberate over North Korea, South Korean President Moon Jae-in has been sidelined in an act of diplomatic isolation locals refer to as “Korea passing”, denoting the way major players have ignored, undermined or openly opposed South Korea when it comes to handling the North Korea crisis.

Despite US President Donald Trump’s planned first official trip to East Asia next month – and US Defence Secretary Jim Mattis’ visit to Seoul on Friday for annual defence talks – Korea passing is likely only to worsen as a result of the Japanese general election, in which Prime Minister Shinzo Abe’s Liberal Democratic Party won 61 per cent of the House of Representatives on Sunday, as well as further centralisation of Chinese power under President Xi Jinping at this month’s 19th Party Congress. These events will empower Abe and Xi, whose agendas contravene what Moon is trying to accomplish.

Part of the reason for this is that South Korea has proven itself incompetent when it comes to talking the North down from military provocations. In the month of September alone, North Korea tested its first thermonuclear bomb, fired its longest-ever ballistic missile 3,700km over Hokkaido into the Pacific Ocean and threatened to detonate a hydrogen bomb over the Pacific. This is an unprecedented escalation, yet South Korea is helpless to stop it. Moon has repeatedly made overtures to the North, inviting them to join the 2018 Winter Olympics in Pyeongchang, asking for military talks, trying to arrange family reunions and offering medical aid – but the North has snubbed every attempt.

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Another reason is that Moon and Trump have diametrically opposed approaches to the problem. As a result, the US no longer consults South Korea as much as it once did. While Moon has worked to open dialogue with the regime, Trump has taken a more hawkish line. In August, the US president threatened North Korea with “fire and fury like the world has never seen”, and in his first United Nations General Assembly speech on September 19, he warned he would “totally destroy North Korea”. His secretary of state, Rex Tillerson, tried to walk back the warmongering by saying the US had “direct lines of communication” with the regime and was trying to see whether it wanted to talk. But the next day, Trump tweeted that Tillerson was “wasting his time trying to negotiate with Little Rocket Man”, adding, “Save your energy Rex, we’ll do what has to be done!”

WATCH: Trump counters North Korea threat with ‘fire and fury’

Trump’s aggressive stance has made him a natural partner with Abe, who is famously hawkish toward the North, further isolating South Korea. Before meeting Xi, Trump spoke at length with Abe, but did not bother to contact South Korea’s acting president, Hwang Kyo-ahn. And after the North’s recent nuclear test, Trump called Abe before calling Moon. He has also openly challenged the South over a free-trade deal, the cost of keeping US troops there and only bothered to nominate an ambassador to South Korea last week, after leaving the post vacant for almost seven months. Recently, Trump bitterly characterised Moon’s approach to the North as “appeasement”.

“Trump and Abe are, some say, on a honeymoon,” said Sohn Yul, director of the Centre for International Studies at Yonsei University and an expert in Japanese politics. “So they’re very close and talk over these issues without consulting the South Korean government. There are concerns that because Trump doesn’t know much about the Korean peninsula, he relies on Abe’s view of the issue, and Abe tends to take a hawkish position toward North Korea, while South Korea is less hawkish. In that sense, this Abe-Trump cooperation is easing Korea passing.”

In addition to the US and Japan squeezing South Korea out, Tokyo directly took issue with Moon’s decision to give the North US$8 million in humanitarian aid, a decision he reaffirmed immediately after the recent nuclear test.

Jo Dong-joon, professor of international organisation at Seoul National University, said Korea passing was nothing new. “In the late 1960s and 70s, when Nixon became president and tried to normalise relations with China, Korea and Japan were almost completely abandoned. It’s a perennial problem in East Asia.”

Jo said there had been at least four times when this occurred – from 1949 to 1950, just before the Korean war, when Nixon normalised ties with China, in the late 1960s and 1970s and also right after the end of the cold war, from 1989 to 1991, when the US planned to withdraw all its troops from the South. But while Korea passing has happened before, this time was different, Jo said.

“The common strategic interests of Korea and the United States have been in decline as Korea has become less dependent on the United States. The North Korea issue is not a matter of survival for the United States, but it is for South Korea. So these countries will work together when it comes to non-violent diplomatic measures, but when it comes to violent options, South Korea will have many reservations, and eventually, South Korean strategic interests may be quite different.”

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This may draw Korean strategy into the sphere of Chinese and Russian thinking, but for now at least, Korea has made no friends there, either – while its approach is too dovish for the US or Japan, it has proven too hawkish for China or Russia. Specifically, South Korea chose to deploy the Terminal High Altitude Area Defence, or THAAD, an anti-ballistic missile system to defend against potential North Korean attacks. But Moon flip-flopped on the issue, calling its deployment undemocratic, then agreeing to it, then deciding to delay it by years with an environmental impact study and finally deploying it. China, which says THAAD is a threat to its security, has retaliated with unofficial sanctions on South Korea. And last month, Russian Deputy Foreign Minister Sergei Ryabkov said THAAD raised a question “about our military balances”.

While some question Moon’s competency, others say he is following former Chinese leader Deng Xiaoping’s dictum to “hide your strength, bide your time”.

“I believe that he has been playing his initial hand cautiously, getting ready to step forward with a bold proposal when the time is just right,” said David Mason, professor at Chung-Ang University. “Moon made initial appeals to North Korea but they were sharply rebuffed, and talked to Trump who is obviously irrational and only self-obsessed with being seen as a ‘winner’ in the short term, and has no actual strategy. So Moon is biding his time for now, until things shift against one or both of those idiots – and I think it’s wise.

“It would be hard to believe somebody with so much experience in dealing with North Korea and so much desire for a peaceful resolution does not have some definite strategy and tactics for what to do about it. I would bet he does. It’s just Trump has become a wild card in what was a pretty stable game. So I think Moon has stepped back, even at the risk of seeming clueless and ineffectual. I will be extremely surprised if it turns out that he actually is that.”