The much-anticipated summit between President Donald Trump and North Korean leader Kim Jong Un, scheduled for June 12, is in trouble.

After National Security Adviser John Bolton said last week that the US would seek complete and total North Korean nuclear disarmament, North Korea said publicly that it would never accept such an outcome — and threatened to pull out of the meeting if Washington didn’t adjust its expectations.

North Korea experts see this as a long-overdue reckoning. The truth is that the United States and North Korea have long expected diametrically opposed outcomes from the talks — with the US wanting North Korea to give up its nukes and North Korea demanding recognition as a legitimate nuclear power. But neither side was willing to confront the reality of the situation. We’ve just been stumbling toward negotiations with no clear sense of how this yawning gulf could be resolved.

How did we get here? Robert E. Kelly, a professor at South Korea’s Pusan National University, gave a really clear explanation in a series of Monday morning tweets: It’s all because of South Korean President Moon Jae-in.

Moon is a leftist who took office in May of last year, back when Trump was threatening war with North Korea. He made a deep and concerted effort to try to broker negotiations between Trump and Kim to defuse the tension, and part of his strategy was making grandiose promises about what talks could accomplish — even floating the possibility that Trump could win a Nobel Prize to entice him to the table.

The problem, as Kelly points out, is that this was always a kind of shell game: Moon could never change the fact that the US and North Korea want fundamentally different things. Basically, he argues, this was a gambit to try to convince Trump not to go to war with North Korea — one that may yet fail. Trump and Moon are meeting in Washington on Tuesday to try to fix things, and no one really knows how that conversation will go:

Thoughts on Moon’s meeting with Trump tomorrow: 1) It increasingly looks like the Moon administration overstated North Korea’s willingness to deal. Moon will probably get an earful over that. — Robert E Kelly (@Robert_E_Kelly) May 21, 2018

2a) Moon likely exaggerated this to tie Trump to a diplomatic track to prevent him from backsliding into last year’s war-threats which scared the daylights out of South Koreans. If Trump were less vain and had allowed his national security staff to vet the NK offer, he might have — Robert E Kelly (@Robert_E_Kelly) May 21, 2018

2b) learned this. But instead, he accepted the NK summit offer 45 minutes after he was told of it, without even telling the White House staff, and then drank his own kool-aid watching Fox telling him for weeks that he deserved a Nobel. Now comes the hang-over. — Robert E Kelly (@Robert_E_Kelly) May 21, 2018

3) Flattering Trump into diplomacy is likely also why Moon’s government credited Trump with driving NK to negotiation through maximum pressure and suggested that Trump receive a Nobel peace prize. — Robert E Kelly (@Robert_E_Kelly) May 21, 2018

4) It is an open secret in Korea that this was just flattering Trump to prevent him from starting a war. No one actually believes it. My students & colleagues laugh at the suggestion. No one thought the western media wd actually start seriously debating it. Trump is loathed here. — Robert E Kelly (@Robert_E_Kelly) May 21, 2018

5a) The problem, of course, is that none of this Trump-whispering is true: NK is not going to denuclearize; NK was not driven to negotiate by maximum pressure (they chose to negotiate, because they established nuclear deterrence with the US mainland); and Trump does not deserve a — Robert E Kelly (@Robert_E_Kelly) May 21, 2018

5b) Nobel, because, well, I am pretty sure that threatening national genocide at the United Nations – ‘totally destroy North Korea’ – is a disqualifier. — Robert E Kelly (@Robert_E_Kelly) May 21, 2018

6a) The great irony, which US conservative media will never admit of course, is that Trump actually drove SK to the table, not NK. Trump scared SKs so much last year, that Moon’s approval rating has shot up into the 80s%, even though he won with just 41% a year ago, and approval — Robert E Kelly (@Robert_E_Kelly) May 21, 2018

6b) of the summit process is in the 90s%. So if you are a NK hawk, Trump's rhetoric last year made things worse, not better, by scaring up a dovish consensus for Moon to make concessions and keep Trump at bay. — Robert E Kelly (@Robert_E_Kelly) May 21, 2018

7a) At this point, the best thing to do would be to postpone the summit until greater common ground among the 3 players can be found and let experts on the issues hammer out some consensus. But Moon likely opposes that because any delay could open political space for Bolton, and — Robert E Kelly (@Robert_E_Kelly) May 21, 2018

Trump likely desperately wants this summit for the TV, attn, & a political 'win' he can market at home to change the story f/ his scandals & blunt a looming blue wave. So the summit will prolly still happen, even tho, scarily, w/ 3 weeks to go, no1 really knows how it will unfold — Robert E Kelly (@Robert_E_Kelly) May 21, 2018

It’s clear that the runup to the June 12 meeting will be exciting. But when it comes to US-North Korea tensions, a conflict where the stakes are literally nuclear, it would probably be better if things were a little more boring.