The main opposition Democratic Party of Korea has strongly opposed the state inspection agency’s attempt to investigate former President Moon Jae-in, calling it “political retaliation."

In September 2020, a South Korean official was shot dead by North Korean soldiers. At the time, the Moon administration defined him as a South Korean defector to North Korea. But in June 2022, the Yoon Suk-yeol administration reversed the decision, saying there was no evidence to prove that the official was attempting to defect to the North. In mid-July, the Board of Audit and Inspection launched a full audit of nine institutions, including the Coast Guard, the National Intelligence Service and the National Security Office.

According to local media reports, the Board of Audit and Inspection made a phone call and sent an e-mail to Moon asking for a response to questions concerning the killing of the official in September after a 2 1/2 month investigation. It was apparently trying to directly confirm the facts with Moon about the former government’s process in coming to its conclusion.

Moon’s side expressed strong displeasure with the investigation, according to news reports on Sunday.

Democratic Party spokesperson Park Sung-joon criticized the Yoon administration following news reports of the investigation.

"I am surprised by the reports of the Board of Audit and Inspection notifying former President Moon of a written investigation," he said in a written statement on Sunday. "It has become clear that former President Moon is the target of political retaliation led by the prosecution and the Board of Audit and Inspection that started from the transition committee," he added.

"The shooting of an official in the West Sea is a noncontroversial case," Park said. “We cannot help but be angry at the political retaliation with the Board of Audit and Inspection to insult the retired president," he said.

On Monday morning, some Democratic Party lawmakers held a press conference, saying they will report the Board of Audit and Inspection to the Corruption Investigation Office for High-ranking Officials.

Yoon Gun-young, a former head of Chung Wa Dae’s state affairs planning office during the Moon administration, said in the briefing that he had delivered the Board of Audit and Inspection’s written investigation to Moon on Sept. 30, to which Moon had expressed displeasure, saying it was "very rude."

“The Board of Audit and Inspection has abandoned its political neutrality and shown itself to be subordinate to (the ruling) power, but the truth must be revealed,” Yoon said.

On the other hand, the ruling People Power Party defended the Board of Audit and Inspection, calling the investigation into former President Moon a "natural process."

People Power Party chief spokesperson Yang Geum-hee said in a commentary on Sunday that it was “natural” to check the president's role in an investigation of a murdered Korean national, and in the process of defining the murdered Korean as a defector.

"The Board of Audit and Inspection is a constitutional institution with independent status," Yang said. "We respect all the efforts of the Board of Audit and Inspection to reveal the truth about the shooting of a civil servant in the West Sea.”

Some political commentators see the Yoon administration's move to blame the former administration as an effort to recover his low approval rating.

“This is beyond the scope of the Board of Audit and Inspection. It is the realm of politics. It is like floating a giant advertising balloon to show the public that Moon did something wrong,” said political commentator Park Chang-hwan. “The person responsible for reporting to the president may be subject to investigation, but it is extremely inappropriate to send a letter (directly) to the former president.”

The commentator said it is a problem for President Yoon to use investigations into the former administration as the driving force of state affairs rather than innovation, reform or integration.

Yoon’s rating continues to drop

Yoon’s approval rating has declined since he took office in May due to frequent mishaps and scandals surrounding the first lady, as well as repeated blaming of the former administration.

The Yoon administration ambitiously prepared an overseas trip last month to recover his low ratings, but they fell even further due to multiple mishaps. It began with Yoon having to cancel his condolence visit to Queen Elizabeth II’s coffin, followed by controversial summits with Japan and the US. Then he came under fire for the use of vulgar language recorded on a hot mic.

A poll showed on Monday that an upbeat assessment of state affairs under President Yoon moved downward for the first time in four weeks. According to Realmeter, positive evaluation fell 3.4 percentage points from 34.6 percent to 31.2 percent last week. On the other hand, negative ratings rose 3.8 percentage points from 62.2 percent to 66 percent.

A Realmeter official said Yoon’s rating fell because he responded to the hot mic incident by criticizing the media instead of making an apology. The official predicted that the president’s rating will drop further as debate over the hot mic is expected to continue during a parliamentary inspection.

The parliamentary audit, which begins on Tuesday, is important for the Yoon administration.

If the administration fails to respond to the National Assembly's parliamentary audit appropriately, it could further shake Yoon’s approval rating. The presidential office ordered each ministry to respond to the audit thoroughly.

The ruling and opposition parties are expected to clash head-on as they hold the former and current administrations accountable for their respective alleged wrongdoings.

The ruling People Power Party is set to focus on the controversy over North Korea’s shooting of the official and security situation during the Moon administration, as well as its solar and nuclear power plant policies.

In response, the Democratic Party plans to counter by bringing up a series of diplomatic controversies the sprung up during Yoon’s overseas visit and suspicions related to the relocation of the presidential office.

On top of that, fierce battles are expected over various controversies connected to Democratic Party leader Lee Jae-myung, namely the Daejang-dong and Baekhyun-dong development scandals and the Seongnam FC sponsorship scandal. Also expected to be in the spotlight are allegations against first lady Kim Keon-hee for plagiarism and stock price manipulation.