Moon Jung-in-Given a lunch speech at the 5th South Korea-US China Event on June 16, 2017.(Photo source: Yonhap News Agency)

South Korean President Moon Jae-in and North Korean leader Kim Jong-un issued the Pyongyang Declaration after the third Wen-Kim summit on the 19th, announcing the end of the state of hostility between the two Koreas and specific measures to implement the denuclearization of the Korean peninsula.The warm exchange between the two Koreas is the result of the cooperation of many experts, including Moon Jung-in, a professor at Yonsei University in South Korea who has taught in many universities in the United States. His understanding of North Korean affairs and the channel for dialogue in the United States make him an important driving force behind the scenes.

67-year-old Moon Jung-in was born in Jeju Island and graduated from Yonsei University. He went to the United States to study in 1978 and obtained a master's and doctoral degree from the University of Maryland. He has taught at Williams College, the University of Kentucky, and the University of California, San Diego.,Fluent in English.

His old friend and former president of Jeju University, Gao Chung-seok, said: Moon Jung-in used to write love letters for his classmates, and he knew very well what sweet words to say to girls.In the eyes of friends, Moon Jung-in, who has practiced judo and shot put since childhood, has a sense of justice, does not sit back and watch bullying, has an approachable and gregarious personality, and is also a good drinker.

In 1994, he returned to his alma mater, Yonsei University, as a professor of the Department of Political Affairs and Diplomacy. He also served as an advisor to the National Security Committee of the Office of President Kim Dae-jung.

When Kim Jong-un's father, Kim Jong-il, and South Korean President Kim Dae-jung held the first inter-Korean summit in 2000, Moon Jong-in attended a group meeting.

On April 27 this year, Wen Zhengren made his debut for the first time. At that time, Wen Zhengren flew to New York and Washington to understand the views of important American diplomatic experts on the summit.

Moon Jung-in was very active in the third Wenjinhui, frequently appearing in front of the camera.He told a news conference in Pyongyang after the Wen-Kim meeting that it was Kim Jong Un's decision to intend to visit Seoul, despite efforts by North Korean officials to dissuade him.Moon Jung-in pointed out that the joint declaration of the first summit between the two Koreas stated that Kim Jong-il would visit South Korea, but it came to nothing due to strong opposition from North Korean officials.

Moon Jong-in also said that Kim Jong-un asked Moon Jae-in to bring a personal message to US President Trump who is attending the UN General Assembly, but did not disclose the content of the confidential message.He only said: US Secretary of State Pompeo will visit Pyongyang again soon.

Before the Wen-Kim meeting, Kim Jong-un delivered a personal letter to Trump through channels, proposing to hold a second Trump-Kim meeting.Trump also said on the 24th that the relationship between the United States and North Korea has greatly improved, and the second Trump-Kim meeting may be held soon.For this reason, Cheong Wa Dae summoned Moon Jung-in to discuss how to intervene to facilitate the second Trump-Kim meeting as soon as possible, so as to make progress in US-North Korea relations and North Korea's denuclearization.

A senior U.S. official stationed in Seoul said: "The South Korean president has few experts who speak fluent English, know a lot about the United States, and understand North Korea."

Moon Jung-in's insights often hit the development of inter-Korean affairs.When the situation on the Korean peninsula was tense last year, he called on the South Korean government to think twice about the U.S.-South Korea military exercises in exchange for North Korea stopping missile launches.At the Trump-Kim meeting in June this year, Trump expressed his intention to suspend the US-South Korea military exercises, and Moon Jae-in also expressed his willingness to consider stopping the military exercises.

However, Moon Jung-in's opinion has also caused controversy.He once pointed out that the Yeonpyeong Island shelling incident that killed four South Korean soldiers and civilians in 2010 was South Korea's excessive stimulation of North Korea. Opponents criticized him for over-rationalizing North Korea's behavior.

A person in the diplomatic circles in Seoul commented on Moon Jung-in: I cannot say that he is very close to the president, but it is obvious that he is very important.