SEOUL — ​President Moon Jae-in of South Korea has a message for the United States: President Biden wants to interact now with North Korea.

In an interview with The New York Times, Mr. Moon pushed the American chief to kick-start negotiations with the federal government of Kim Jong-un, the chief of North Korea, after two years by which diplomatic progress stalled, even reversed. Denuclearization, the South Korean president stated, was a “matter of survival” for his nation.

He additionally urged the United States to cooperate with China on North Korea and different points of world concern, together with local weather change. The deteriorating relations between the superpowers, he stated, might undermine any negotiations over denuclearization.

“If tensions between the United States and China intensify, North Korea can take advantage of it and capitalize on it,” Mr. Moon stated.

It was half plea, half gross sales pitch from Mr. Moon, who sat down with The Times because the United States tries to rebuild its relationships within the area with a watch to countering China’s affect, and North Korea builds up its nuclear arsenal. Mr. Moon, who is about to satisfy with Mr. Biden subsequent month in Washington, appeared able to step as soon as once more into the function of mediator between the 2 sides.

In the interview, Mr. Moon ​was pleased with his deft diplomatic maneuvering in 2018, when he steered the 2 unpredictable leaders of North Korea and the United States to satisfy in particular person. He was additionally pragmatic, tacitly acknowledging that ​his work to realize denuclearization and ​peace on the Korean Peninsula has since unraveled.

President Donald J. Trump left workplace with out eradicating a single North Korean nuclear warhead. Mr. Kim has resumed weapons checks. ​

“He beat around the bush and failed to pull it through,” Mr. Moon stated of Mr. Trump’s efforts on North Korea. “The most important starting point for both governments is to have the will for dialogue and to sit down face to face at an early date.”

Now in his closing 12 months in workplace, Mr. Moon is decided to begin once more​ — and is aware of he faces a really totally different chief in Mr. Biden.

Mr. Moon guess on Mr. Trump’s type, emphasizing personality-driven “top-down diplomacy” by way of one-on-one conferences with Mr. Kim. Mr. Biden, he stated, was returning to the normal “bottom-up” strategy by which negotiators haggle over particulars earlier than looking for approval from their bosses.

“I hope that Biden will go down as a historic president that has achieved substantive and irreversible progress for the complete denuclearization and peace settlement on the Korean Peninsula,” Mr. Moon stated within the interview from Sangchunjae, a conventional hanok on the grounds of the chief residence, Blue House.

Mr. Moon’s go to to Washington comes at an important second. The Biden administration is wrapping up its monthslong coverage assessment of North Korea, one of the crucial urgent geopolitical points for the United States.

​Mr. Biden ​has began reversing a lot of his predecessor’s international coverage selections​. But Mr. Moon ​warned that it could be a mistake to kill the 2018 Singapore settlement between Mr. Trump and Mr. Kim ​that set out broad objectives for denuclearizing the Korean Peninsula. ​

“I believe that if we build on what President Trump has left, we will see this effort come to fruition under Biden’s leadership,” he stated.

Mr. Moon referred to as for the United States and North Korea to ​transfer in “gradual and phased” ​steps towards denuclearization​, exchanging concessions and incentives “simultaneously”​ alongside the best way. It was a well-worn script for Mr. Moon, who paused often through the interview to reference his notes and punctuated his speech with small but resolute hand gestures.

Some previous American negotiators and Mr. Moon’s conservative critics dismiss such a technique, saying North Korea would stall and undermine worldwide sanctions, one of the best leverage Washington has towards the impoverished nation. In its annual threat assessment launched final week, the United States’ director of nationwide intelligence stated Mr. Kim “believes that over time he will gain international acceptance and respect as a nuclear power.”

But Mr. Moon’s staff argues that the phased strategy is essentially the most sensible, even whether it is imperfect. As his administration sees it, North Korea would by no means surrender its arsenal in a single fast deal, lest the regime lose its solely bargaining chip with Washington.

The key​​, Mr. Moon stated, is for the United States and North Korea to work out a “mutually trusted road map.”

American negotiators beneath Mr. Trump by no means made it to that time. Both sides couldn’t even agree on a primary step for the North and what reward Washington would supply in return.

Mr. Moon will not be solely scrambling to salvage his “Korean Peninsula Peace Process” but additionally arguably his biggest diplomatic legacy.

As his North Korea coverage has faltered, critics have referred to as him a naïve pacifist who guess an excessive amount of on Mr. Kim’s unproven dedication to denuclearization.

“His good intentions brought bad consequences,” stated Kim Sung-han, a professor at Korea University. “His mediation has not worked nor do we have progress in denuclearization. His time is running out.”

Since the negotiations have stalled, Mr. Moon’s troubles at house have mounted. His approval rankings have plunged to report lows amid real-estate and different scandals. This month, indignant voters delivered crushing defeats to his Democratic Party within the mayoral elections in South Korea’s two largest cities.

That is a pointy flip of fortune from the beginning of his administration, when Mr. Moon parlayed a hair-raising geopolitical disaster right into a signature coverage initiative.

“When I took office back in 2017, we were really concerned about the possibility of war breaking out once again on the Korean Peninsula,” he stated.

Four days into his tenure, North Korea launched its Hwasong-12 intermediate-range ballistic missile that it stated might goal Hawaii and Alaska. Then the North examined a hydrogen bomb and three intercontinental ballistic missiles. In response, Mr. Trump threatened “fire and fury,” as American Navy provider teams steamed towards the peninsula.

Mr. Moon’s first diplomatic win got here when Mr. Kim accepted his invitation to ship a delegation to the 2018 Winter Olympics in Pyeongchang, South Korea. Soon after, Mr. Moon met with Mr. Kim on the closely armed inter-Korean border.

During that assembly, Mr. Moon stated the North Korean dictator intimated that disarmament was an actual chance. “If safety can be guaranteed without nuclear weapons, why would I struggle to hold onto them even at the cost of sanctions?” Mr. Moon recalled Mr. Kim saying.

He stated he made that pitch to Mr. Trump, imploring him to satisfy Mr. Kim. At their made-for-TV summit in Singapore, Mr. Trump promised “security guarantees” for North Korea whereas Mr. Kim dedicated to “work toward complete denuclearization of the Korean Peninsula.”

“It’s clearly an achievement for President Trump that he held the first-ever summit meeting between North Korea and the United States,” he stated.

But Mr. Moon additionally lamented that Mr. Trump by no means adopted by way of, after declaring that “there is no longer a Nuclear Threat from North Korea.” When Mr. Kim and Mr. Trump met once more in 2019 in Hanoi, Vietnam, the negotiations went nowhere, and the boys left with out an settlement on easy methods to transfer ahead with the Singapore deal.

While Mr. Moon was cautious to dole out reward for Mr. Trump, he additionally appeared pissed off by the previous president’s erratic habits and Twitter diplomacy. Mr. Trump canceled or downsized the annual joint navy drills that the United States conducts with the South and demanded what Mr. Moon referred to as an “excessive amount” to maintain 28,500 American troops in South Korea.

Mr. Moon stated he had determined to droop negotiations over the so-called protection cost-sharing settlement throughout Mr. Trump’s final months in workplace. South Korea was prepared to pay extra, given its rising financial dimension, however Mr. Trump’s calls for violated the muse of the 2 nations’ relationship.

“His demand lacked reasonable and rational calculation,” Mr. Moon stated.

The truth, he stated, that Washington and Seoul might strike a deal inside 46 days of Mr. Biden’s inauguration was a “clear testament to the importance President Biden attaches to” the alliance.

Mr. Moon is hopeful in regards to the progress the brand new American chief could make on North Korea, though any important breakthrough could also be unrealistic, given the deep distrust between Washington and Pyongyang.

Mr. Biden stated final month that he was “prepared for some form of diplomacy” with North Korea, however that “it has to be conditioned upon the end result of denuclearization.”

North Korea has supplied concepts on a phased strategy beginning with the demolition of its only-known nuclear test site, adopted by the dismantling of a rocket engine take a look at facility and the nuclear advanced in Yongbyon north of Pyongyang.

Mr. Moon stated he believed such steps, if matched with American concessions, might result in the elimination of the North’s extra prized property, like I.C.B.M.s. In that state of affairs, he stated, the transfer towards full denuclearization turns into “irreversible.”

“This dialogue and diplomacy can lead to denuclearization,” he stated. “If both sides learn from the failure in Hanoi and put their heads together for more realistic ideas, I am confident that they can find a solution.”