A high-profile South Korean presidential adviser blamed both parties for the failure of last month’s North Korea-US summit in Hanoi, Vietnam, saying Pyongyang was overconfident and Washington had sought too big a deal.

While Moon Chung-in was confident that dialogue would continue, he warned that momentum could dwindle, that inter-Korean ties face roadblocks, and that a new North Korean missile test would be disastrous.

Moon, who was speaking as a private citizen rather than in his position as special adviser to the Blue House on diplomacy, national security and unification affairs, is an academic and longtime North Korea specialist. Not related to South Korean President Moon Jae-in, he is widely seen as the key architect of the “Sunshine Policy” of engagement with North Korea, which persisted under two liberal administrations from 1998-2008.

Though respected by academics and journalists for his knowledge, candor and lack of fear of controversy, Moon frequently infuriates conservatives in South Korea and the United States for what they consider to be his pro-North Korea bias.

Speaking before senior journalists in Seoul on Tuesday, Moon admitted his surprise and disappointment at the failure of the two delegations to reach a deal in Hanoi.

“I expected a lot from the Hanoi summit – we could have found a breakthrough and [North Korean leader Kim Jong Un] could have come to Seoul – but it broke down,” he said, referring to a promise Kim made during last October’s inter-Korean summit in the North Korean capital of Pyongyang. Kim was supposed to visit Seoul in December in what would have been a historic first trip to the south by a North Korean leader, but cancelled for reasons which remain murky.

Pre-summit preparations between the US and North Korean “were not well arranged,” Moon alleged. Hawkish US national security adviser John Bolton had been scheduled to fly to South Korea for prior consultations, he said, but in the event flew directly to Hanoi.

During the summit, Kim offered to dismantle his central nuclear facility at Yongbyon, where the state’s plutonium is processed; experts believe the facility encompasses 50-80% of North Korea’s nuclear programs. “Kim Jong Un offered Yongbyon as the only measure,” Moon said. “By dismantling Yongbyon they thought they would get a small deal, but the US wanted a big deal, a one-time solution.”

‘Yongbyon plus alpha’

Referring to what the Americans call “Yongbyon plus alpha” and what North Korean Foreign Minister Ri Yong Ho has called “Yongbyon plus one,” he speculated that the deal breaker was North Korea’s secretive highly enriched uranium (HEU) program.

Moreover, the two sides differed over the process, with the North Koreans favoring a phased step-by-step denuclearization with sanctions relief, while the Americans sought a major deal that would wrap everything together.

“The difference between North Korea and the US is ‘all for all’ versus ‘all or nothing,’” Moon said. He added that US Special Envoy Stephen Biegun had referenced a step-by-step process in the lead-up to the summit, but in fact, the US delegation offered a surprise “yellow envelope.” Delivered to the North Korean delegation by Bolton, it is believed to have outlined a wide range of sites in the North.

The North Korean delegation also “made a mistake,” Moon suggested: “North Korea was too proud. They thought that, after Singapore, they got a satisfactory result.”

Moon referred to problems both leaders were facing at home that may have overshadowed the summit. Trump was distracted by the hearing of his former lawyer Michael Cohen, which his opponents had scheduled for the day of the summit, while Kim “is likely faced with economic difficulties … he might face some enemies, and some trouble in North Korea.”

On the upside, Moon noted that North Korea’s post-summit state media had not turned hostile toward the US, even amid military drills currently under way in the South. “If North Korea is going to break off negotiations, they will start propaganda against the US,” he said, adding that Kim’s public statements continue to focus on the economy rather than military or strategic matters. “I don’t think the dialogue table is broken,” Moon said.

He also doubted that Kim would purge his key aides after Hanoi, as some South Korean media have suggested.

But though Moon said that both Pyongyang and Washington are “being careful with each other,” he urged President Moon to continue to play a mediating or facilitating role. “We could lose momentum,” the adviser fretted. “We should prevent the US from going off-track; if the dialogue channel is derailed, it might be difficult to open it again.”

Rocket risks played down

Moreover, the clock is ticking on the Trump presidency. Noting that Kim has said he wants to complete denuclearization within Trump’s term, Moon warned: “If a Democrat is elected in the next election, policy toward North Korea could completely change.”

In the near term, Moon played down the likelihood of additional US sanctions. “Without a North Korean provocation, I don’t think it is desirable to apply additional sanctions,” he said. “Biegun said this, so I don’t think dialogue is finished.”

Many observers have opined that the real loser from the no-deal summit was South Korea’s pro-engagement president, and Moon conceded that an inter-Korean summit looks distant. “It is not easy to hold an inter-Korean summit at this moment as we don’t have anything to offer,” he said. “The condition of Kim’s visit to Seoul was a resumption of the Kaesong and Mount Kumgang projects.”

Those two inter-Korean projects, a joint industrial complex and a tourism facility, were widely regarded as flagships of the 1998-2008 “Sunshine Policy,” though they were also criticized for supplying cash to the Pyongyang regime. Both were halted by conservative Seoul administrations, and look impossible to restart unless international sanctions are waived or eased.

For these reasons, Moon suggested that Kim is more likely to meet with Chinese President Xi Jinping before summiting with his South Korean counterpart again.

Moon explained why North Korea, which has feared US military action for decades, continues to maintain its strategic assets. “North Korea’s survival strategy is hedging,” he said. “We might think it is cheating; they think it is hedging.”

Despite his belief that dialogue will survive, Moon admitted being discouraged by the current state of play. On a recent trip to Washington, he said he had met with around 100 North Korea-related professionals, and “about 80% of them are pessimists or cynics.”

He said he was not always convinced of intelligence coming from the US; recently, think-tanks, citing satellite imagery, have noted signs of activity at satellite and missile sites in the country. He suggested that the widely reported site activity might be “trivial,” but warned that a North Korean missile test at this time could be a “big disaster.”