Then-President Moon Jae-in, left, and then-Prosecutor General Yoon Suk Yeol walk side by side at Cheong Wa Dae following Yoon's appointment ceremony to lead the prosecution, July 25, 2019. Korea Times file

Over the past three decades, Hahm Sung-deuk has closely observed the unfolding of various political events, and how they have influenced the decisions of different presidents, which either bolstered or undermined their leadership.

Hahm, dean and Naun Professor of Political Science and Law at Kyonggi University's Graduate School of Political Studies, has focused his studies on presidential leadership, aiming to understand why some leaders succeed in the highest government position, while others fail. His academic focus has granted him rare access to several presidents, as well as both former and current political leaders.

Hahm sat down and interviewed presidents for his books and academic papers, and through these interactions, he developed personal bonds with some of them.

In his recently published book, "Presidential Crisis in Korea," he characterizes former President Moon Jae-in as a failed leader. He claims that a couple of self-destructive choices made by Moon helped then-Prosecutor General Yoon Suk Yeol build a career breakthrough, ultimately positioning him as Korea's next president.

One of his claims is that Moon's controversial nomination of Cho Kuk as justice minister in 2019 was a critical mistake, which triggered Yoon's rapid rise to presidency.

"President Moon's fate would have been very different if he hadn't appointed Cho as justice minister," Hahm told The Korea Times. "President Moon was a rare leader who enjoyed solid support for most of his presidency due to his fervent fan-like supporters. If he had not nominated Cho for justice minister, Moon would not have clashed with the prosecution led by Yoon, who attempted to remain loyal."

Hahm added that it would have been best for Moon if Cho had completed his public service as senior secretary for civil affairs without being appointed to serve as justice minister.

Unlike presidential secretaries, Cabinet ministers are required to undergo a National Assembly confirmation hearing before taking up the positions for which they had been nominated. The results of these hearings are not binding, allowing presidents to appoint their picks regardless of the decisions of lawmakers. However, holding a confirmation hearing is a necessary process to formalize the appointment.

Lawmakers, particularly from the opposition, often use the confirmation hearing as an opportunity to discredit the president and the ruling party. They scrutinize the nominees' past professional experiences and private lives to determine whether the nominee is ethically and professionally suitable for the job.

As lawmakers delved into Cho's background, they uncovered numerous suspicions regarding his financial activities and allegations of his and his wife's involvement in forging certificates to facilitate their children's admission to universities and graduate schools. As suspicions surrounding him grew, the fallout also affected the president.

Despite this, Moon proceeded with the appointment of Cho, a decision that ultimately backfired on him, according to Hahm.

Moon's controversial nomination ironically became a career breakthrough for the prosecutor general, who emerged as a rising star among the public. Yoon directed the prosecution to initiate an investigation into Cho despite opposition from core ruling camp members who viewed the probe as a politically self-destructive move.

Hahm Sung-deuk, dean and Naun Professor of Political Science and Law at Kyonggi University Graduate School of Political Studies / Korea Times photo by Choi Won-suk

Hahm said the president and the prosecutor general trusted each other, while Yoon endeavored to meet the expectations set by his appointer.

Their ties, however, were put to the test twice: first when Yoon directed the prosecution to investigate Cho, and second, when the prosecutor general initiated a probe into the presidential office's alleged meddling in a 2018 mayoral election in Ulsan to give an advantage to the president's decades-old friend, who ran in the election on the Democratic Party of Korea's ticket.

According to Hahm, the investigation into Cho did not affect their bond because they were on the same page about the Cabinet minister. But Yoon launching the probe into the election meddling case was different. It infuriated Moon.

Cover of "Presidential Crisis in Korea"

In his book "Presidential Crisis in Korea," officially released on March 6, Hahm revealed an exclusive story about the Moon-Yoon meeting held on Sept. 6, 2019, three days before Cho assumed the helm at the justice ministry.

At Yoon's request, he had a private meeting with Moon, securing the president's approval to proceed with investigating Cho. The book reveals that both Moon and Yoon were in agreement regarding the investigation.

Hahm said his findings debunk the previously held belief about Yoon's motive behind the investigation into Cho.

"Back in 2019, the prevailing narrative suggested that Yoon sought to halt Cho's efforts for prosecutorial reform, which prompted the probe into the justice minister. However, this narrative is incorrect," he said.

Hahm said he embarked on writing the book to share his findings with readers, aiming to illustrate the dual aspect of political power: the truth can often differ from what is commonly known.

He emphasized that "academic necessity" served as a crucial motivator that drove him to take the risk of potential legal repercussions in order to publish the book.

"In the United States, political scientists, especially those focused on presidential studies, have ample data and empirical studies at their disposal for researching presidential leadership. For instance, journalists like Bob Woodward have authored numerous books about U.S. presidents, drawing from interviews and investigations. Political scientists in the U.S. can utilize such resources for their research. However, in Korea, we lack similar resources," he said.

The release of Hahm's book just weeks before the April 10 general elections may invite criticism, with some suggesting that he is attempting to influence the election results.

But he refuted such suggestions, stating that the timing of his book's release was coincidental and not intentional. He clarified that he had not planned for it to be published just before the elections.

"I began working on the book four and a half years ago, and its publication now coincides with the recent closure of the related cases mentioned in my book. Both the district court and the upper court ruled against Cho, and last year, there was another ruling regarding the election meddling case in Ulsan that sided with the prosecution," he said.

He said he had to revise portions of the book, particularly editing phrases concerning certain politicians that he believed might prompt readers to question his motives. Additionally, he updated the information to ensure it remained current and up-to-date.

"Publishing this book was a tough decision. My family members expressed concerns about the potential impact it could have on me. However, I was resolute in my determination to proceed because, as a scholar, I believed it was my duty to do so," he said.

"Presidential Crisis in Korea" is available for purchase both in bookstores and online.