North Korea, by contrast, followed a step-by-step road map in pursuit of international prestige, sanctions relief, and economic aid for its impoverished citizens. During 2017, Kim conducted testing that established his regime's nuclear capability, despite Trump's pledges of "fire and fury" in response to potential aggression.
In 2018, Kim turned to a charm offensive with South Korean President Moon Jae-in. Moon and his South Korean constituents seemed more alarmed by White House threats than North Korea did.
Kim's charm offensive also worked on Trump, the self-styled dealmaker who had previously taunted the North Korean dictator as "Little Rocket Man." The administration printed commemorative summit coins depicting Trump and "Supreme Leader" Kim as peers — a longstanding objective of North Korean leaders.
When Kim released three imprisoned Americans earlier this month, Trump praised him for having been "excellent to these three incredible people." Basking in flattery from Moon and Republicans, the smiling president recently said "everyone thinks" he deserves the Nobel Peace Prize.
Yet weeks passed without clarity on North Korea's real intentions. After two trips to Pyongyang, Trump's new secretary of State, Mike Pompeo, did not identify common ground on summit objectives.
"He needed to have Pompeo come back with some very specific points," said Hill, the former ambassador to South Korea. "Elementary due diligence."
Two related developments finally triggered Trump's cancellation.
John Bolton, who became national security advisor in April after Trump dumped H.R. McMaster, invoked the "Libya model" for North Korean denuclearization. Years after Libyan dictator Moammar Gaddafi gave up his nuclear weapons, he was overthrown and killed.
North Korea blasted Bolton. Kim's government declared that, as most Western experts on the region had anticipated, it would not surrender its nuclear weapons.
At the White House, where South Korea's Moon traveled to salvage the summit, Trump promised to make North Korea rich and guarantee its dictator's safety. He vacillated on whether he would insist on immediate denuclearization or accept a gradual approach.