Trump's 'great chemistry' with Kim Jong Un put to test at summit

Trump has hailed his "great chemistry" with Kim and voiced delight at "beautiful letters" from the totalitarian leader 30 years his junior.

Trump points out that North Korea has not tested a nuclear bomb or long-range missile in more than a year and says he has saved the world from a devastating war -- a feat for which, he is not shy to say, he believes he deserves the Nobel Peace Prize.

But North Korea's nuclear program remains intact and the Kim dynasty, which has reigned with an iron fist for six decades, is skilled at the art of biding time.

The most atypical of US presidents, Trump has taken a path rejected by his predecessors -- negotiating face-to-face with the leader of the reclusive regime. And the real estate mogul believes that his style -- direct and brash -- can succeed where years of diplomatic drudgework with Pyongyang have failed.

'No rush,' says Trump

Michael O'Hanlon, a senior fellow at the Brookings Institution, said that Trump had laid the groundwork for the "possibility of progress," even if the prospects remain uncertain.

"A combination of fear and pain, combined with hope for a better future, may be just the right juxtaposition of sentiments to have instilled in Kim's mind," O'Hanlon said.

"Whether through design or chance, or a bit of both, Trump managed to achieve this mix by 2018," he said.

Trump himself has stayed evasive on what he hopes to achieve in Hanoi, which follows up the historic first summit between the two leaders in Singapore in June.

"I think that North Korea and Chairman Kim have some very positive things in mind, and we'll soon find out," Trump told reporters on Tuesday.

"But I'm in no rush. There's no testing. As long as there's not testing, I'm in no rush," he said.

The two countries remain divided on the very meaning of denuclearization, with the United States wanting North Korea to give up its arsenal and Pyongyang supporting a more general end to nuclear weapons in the region.

What if months or even years go by and North Korea gives up nothing significant?

"I think Trump is calculating that he can run out the clock at least until the end of his first term with this strategy," said Vipin Narang, an associate professor at the Massachusetts Institute of Technology.

"A lot may depend on what Hanoi yields," he said.

Eye on 2020, or beyond?

For Christopher Green, an expert on Korea at the International Crisis Group, the issue of the calendar is central.

Trump faces re-election next year and has already touted North Korea as an achievement, telling Americans after the Singapore summit that they can "sleep well tonight!"

"The major concern is that Trump may be too keen to bring about something that looks to naive, glimpsing eyes like a foreign policy achievement, and won't do the essential legwork to ensure that a durable agreement is reached," Green said.

"Something that looks like an achievement during his time in office may not have the necessary durability to radically alter the face of Northeast Asia," Green said.

"We need to look beyond November 2020 and toward 2030 or 2040. Only then will we know."

And with heads of state personally conducting the diplomacy, there may be little recourse if a new crisis erupts.

Little more than a year ago, relations were in crisis and the two leaders were trading insults in an extraordinary personal way, with Trump calling Kim "little rocket man" and North Korean media branding Trump the "mentally deranged US dotard."

Trump, who now respectfully addresses the young leader as "Chairman Kim," may seize on any symbolic show to prove his diplomacy is working, such as a North Korean offer to destroy -- again -- part of its key Yongbyon nuclear complex.

"The risk is if Kim decides this unilateral testing moratorium -- because it's not in writing -- no longer works for him," Narang said. "Then there is no diplomatic exit ramp."