SEOUL (Reuters) - In 1989, a 22-year-old South Korean student caused an uproar when she sneaked into North Korea and was filmed advocating for unification and meeting then leader Kim Il Sung.

Im Jong-seok, the Chief Presidential Secretary for President of South Korea Moon Jae-in, greets Kim Yo Jong, the sister of North Korea's leader Kim Jong Un, during a banquet at a hotel in Seoul, South Korea, February 11, 2018. The Presidential Blue House/Yonhap via REUTERS

The unauthorized visit was orchestrated by Im Jong-seok, a prominent student democracy activist who is now chief of staff of South Korean President Moon Jae-in.

Nearly 30 years on, the 51-year-old Im is now playing a pivotal role in an inter-Korean detente fostered by the Winter Games in Pyeongchang, officials and experts say.

The liberal South Korean president is banking on Im, and a handful of other key players, to rebuild inter-Korean ties strained by nearly a decade of conservative rule in the South and the North’s accelerating nuclear and missile programs.

But for critics in the South, Im is at the center of concern that Seoul may prioritize cross-border rapprochement over an air-tight alliance with the United States. Already, they fear, the Winter Olympics has become a propaganda tool for the North.

SPECIAL ENVOY?

After North Korean leader Kim Jong Un made a surprise invitation for Moon to visit Pyongyang last week, Im is now being floated as a possible special envoy to North Korea to discuss the proposal.

South Korea’s intelligence service chief Suh Hoon and Unification Minister Cho Myong-gyon are among the other candidates under consideration, according to officials who spoke on the condition of anonymity.

Suh and Cho both served in an earlier liberal administration that spearheaded the “sunshine” policy of inter-Korean engagement.

A beaming Im attended a meeting and lunch Moon hosted for Kim Jong Un’s sister, Kim Yo Jong, at the presidential Blue House on Saturday. Im also hosted a farewell dinner for Kim’s delegation on Sunday.

“Today you can just make yourself comfortable and eat,” Im told guests, according to a senior Blue House official who attended the dinner.

Slideshow ( 2 images )

Back in his student days, Im was imprisoned for three-and-a-half years for violating national security laws for his role in the unauthorized visit to North Korea by the student, who was also arrested on her return.

Im, who declined to comment for this article, has hit back at accusations he and his fellow former student activists are pro-North Korea.

“Most of the people you mentioned (former activists) have risked their lives to fight for democracy,” Im told a lawmaker in parliament last November. “I have not led a shameful life”.

WARMER HEART

Many student activists during South Korea’s military rule in the 1980s studied and even sympathized with the North’s ruling ideology of Juche - a concoction of Marxism and an extreme form of go-it-alone nationalism championed by Kim Il Sung.

“Now we see things with a much more skeptical eye, having been to the North and seen it for ourselves,” said Lee In-young, another former activist and now lawmaker of Moon’s party.

“We’re not North Korea sympathizers, as some would put it, but may have a warmer heart and more patience than others toward peace.”

Known for his affable character and coordination skills as Moon’s chief of staff, Im has deeply engaged himself in everything from policymaking to personnel appointments at the Blue House while shunning the limelight.

Im oversaw Moon’s speeches at key anniversaries where the president voiced his opposition to war and said he willing to return to dialogue with the North if it stops nuclear and missile tests.

SEEKING TALKS

Officials, however, said they are leaning more toward Suh or Cho, given conservative criticism of Im.

“I know there are many names being mentioned, but Suh is an expert and would be the best choice,” said Chung Se-hyun, a former unification minister, who regularly advises Moon on inter-Korean affairs. “In inter-Korean relations, it is critical to understand the North’s language, their way of talking and the country’s inner workings.”

Suh led a series of talks in the run up to two inter-Korean summits, first in 2000 and then 2007. Suh, as a top spy official, and Moon, then chief of staff to President Roh Moo-hyun, were instrumental in setting up the 2007 meeting.

The Blue House said Im is playing the “natural role” expected as chief of staff, without elaborating.

But his ubiquitous presence during the Olympics-related detente contrasts with National Security Advisor Chung Eui-yong, who was only invited to the Blue House lunch, and other top foreign and defense officials who were nowhere to be seen.

Moon has appointed scholars and former liberal administration officials to many of the top diplomatic posts including foreign minister.

“It’s natural for the unification ministry to lead the ongoing developments, and the Blue House is an overseer as it has always been,” a foreign ministry official told Reuters.

“Our job is to create conditions for talks between the North and the United States, which means a long and tough road ahead and that’s where we would play our role.”