Chun, however, suggested that conservatives shouldn’t be so quick to shut down debate about the painful compromises that denuclearizing North Korea may require. “In terms of our security interests, I think” a partial U.S. troop withdrawal is something that “we have to be prepared to live with,” he said. “If Korean conservatives camp on their existing comfort zone, I think there will be no solution” to the North Korean nuclear crisis.

Given his involvement in the six-party talks, which collapsed in 2009, Chun is well aware of how elusive a solution has been. But he’s also not willing to consider a drawdown of U.S. troops for just any solution. He told me, for instance, that he would not support a pact in which the United States and South Korea trade a partial withdrawal of American forces for only a partial dismantling of North Korea’s nuclear-weapons arsenal.

Chun is skeptical that Kim Jong Un is truly committed to doing away with his nuclear weapons. What Chun has learned over decades of dealing with North Korea is that the North speaks of a nuclear-free Korean peninsula the way nuclear-weapons powers including the United States speak about a nuclear-free world—as “a long-term, distant aspiration of humanity,” he said. Kim “will try to hold as much [of his] nuclear arsenal as possible for as long as possible,” he told me. (Trump, by contrast, said this week that he would prefer North Korea denuclearize “over a very short period of time,” though he notably did not insist on such an approach.)

Still, Kim’s interest in receiving massive assistance to develop the North Korean economy might motivate him to make surprisingly big concessions, Chun reasoned, if only because he’s now confident that he will retain the scientific and industrial know-how to rebuild his advanced nuclear arsenal in short order even if he gives up all his nuclear bombs and enrichment capabilities. (If Kim, a young ruler for life, decides to reconstitute the nuclear program in 10 years, when the term-limited President Trump and President Moon are long out of office, he’d be doing so while presiding over a country that could be “10 times stronger than now economically,” Chun mused. “It’s a piece of cake!”) Chun expects North Korea to also seek security guarantees that would reverse what it perceives as America’s “hostile policy”: a nonaggression pact, the normalization of relations between the United States and North Korea, a peace treaty, and potentially the withdrawal of U.S. forces from South Korea, though the North might refrain from this last demand and let “anti-American elements in South Korea ... take care of this problem” by driving out the U.S. military in the euphoric wake of a peace accord.

Chun claimed that many of Moon’s advisers are “uncomfortable with” the U.S. alliance and “built up their careers as anti-American activists,” though their views “may have evolved over time,” citing as an example Moon’s chief of staff, who was once imprisoned for helping a fellow student activist make an unauthorized visit to North Korea in 1989. But he acknowledged that Moon has emphasized the importance of the U.S. alliance and dismissed talk of removing U.S. forces. “The best scenario for Moon Jae In,” if a troop withdrawal has to happen, “is that Trump makes the decision and it looks as if [Trump’s] decision is forced on” Moon, which makes it “easier to sell it to the Korean public,” Chun said. On Tuesday, during a meeting with Trump at the White House, Moon attached an array of high hopes to the U.S. president’s negotiations with Kim Jong Un: not just denuclearization, but also ending the Korean War, establishing diplomatic ties between the U.S. and North Korea, and establishing a “permanent peace regime.” The “fate and the future of the Korean peninsula hinge on this,” Moon said.