SEOUL - As campaigning gains momentum in South Korea's presidential race, controversy is swirling around the misdeeds of the wives and families of the two main candidates, causing both to falter in opinion polls.

Main opposition candidate Yoon Suk-yeol, a former prosecutor-general who championed fairness, found himself in a bind after it was revealed that his wife Kim Keon-hee falsified her credentials in job applications and was linked to a stock manipulation case.

His mother-in-law was handed a year's jail for forging a financial document to buy land.

The son of ruling party candidate Lee Jae-myung, meanwhile, was found to have engaged in gambling online and accused of paying for sexual services.

The past of Mr Lee's wife Kim Hye-gyeong has also come back to haunt her - she allegedly posted defamatory messages about his political rivals in 2018. She was grilled by prosecutors but the case was dropped due to a lack of evidence.

More dirt has been dug up in recent weeks.

Mr Kim Chang-in, spokesman for the minor opposition Justice Party's election committee, voiced frustration that "this is becoming the election of dysfunctional families".

He lamented that the two major candidates have shown no major vision or policies.

The Hankyoreh newspaper noted that the opposing camps are more focused on "stirring up conflict and provoking hatred".

The spotlight on the candidates' families can be attributed to the belief that a leader must manage himself and his family well in order to run a country well, according to political science professor Kim Jae-chun from Sogang University.

"How the candidate's wife, children, siblings and family live their life will also be in the mind of voters when they are deciding for whom to vote," he told The Straits Times.

They go to the polls on March 9 next year to elect a new president.

Nepotism has been the bane of the country's leaders, even as they pledged to eradicate corruption and power abuse.

Former president Park Geun-hye went as far as severing ties with her brother and sister to prevent nepotism, but failed to rein in a confidante whose appetite for power and bribes led to Ms Park's downfall.

Experts have warned that the mudslinging in the current campaign will affect the candidates' reputation and popularity.

Mr Lee of the ruling Democratic Party (DP) and Mr Yoon of the main opposition People Power Party (PPP) are locked in a neck and neck race.

Polls last week showed that their approval ratings have fallen, most notably among young swing voters in their 20s.

The most recent Realmeter poll put Mr Yoon ahead with 44.4 per cent (down 0.8 percentage point). Mr Lee drew 38 per cent (down 1.7 percentage points).

Mr Yoon's approval rating among those in their 20s dipped 2.8 percentage points, while Mr Lee's fell 1.4 percentage points.

A Realmeter representative said the downward trend is influenced by criticism that both candidates are lacking in strong policies and engaging in mudslinging instead.

"It is impossible to say which candidate has the upper hand among the 20s and 30s because their level of loyalty is not high," he said.

"Their support for each candidate can change freely due to the candidate's remarks or controversies."

Policy studies professor Park Sang-byeong from Inha University said the controversy surrounding Mr Yoon's wife must have hurt the candidate and "dealt a heavy blow to young people who thought they were allies of the PPP".

Young voters who voted current President Moon Jae-in into power in 2017 now feel betrayed by his administration's double standards and failed economic policies.

They went all out to vote against the DP in two major by-elections earlier this year, allowing the PPP to win by large margins.

Prof Kim said the family scandals would be "quite damaging" to Mr Yoon, as voters have a higher expectation of him given his reputation as a fearless prosecutor who ousted former president Park.

"It also has to do with Yoon's harsh handling of the Cho Kuk trial," Prof Kim added, referring to how Mr Yoon led an investigation into the former justice minister for tax evasion, conducting illegal business activities, and falsifying documents to help his daughter enter a medical school.

"If you apply the same standards to Yoon Suk-yeol, he won't be free from all the wrongdoings of his family as well."

Prof Kim expects Mr Yoon's wife to be "silent and very low profile" and not play any role throughout his campaign.

Mr Yoon has apologised for the controversy surrounding his wife. He acknowledged that it was "at odds with the fairness and common sense that I advocate".

Mr Lee has also apologised for his son's gambling scandal but insisted that the younger man did not visit a massage parlour for sex.

Prof Kim said Mr Lee, former mayor of Seongnam city and governor of Gyeonggi province, will suffer less damage as people's expectations of him and his family are "quite low".

"It's already been revealed in the past that Lee and his family are not really ethical people," said Prof Kim.

"But people will still vote for him because he is a leader who can deliver."

On social media, comments about the two major candidates run the gamut.

Haters of Mr Lee call him "master of political deception", while those against Mr Yoon feel that he is too arrogant.

A recent poll showed that one out of four respondents has either changed his vote or is considering to do so.

Business owner Sue Hong, 46, said: "There is no better man to vote for so I might not vote."

The scandals

Mr Yoon Suk-Yeol and family

 • He and his wife Kim Keon-hee (both left) were accused of corruption after her company, an art events organiser, received significant sponsorship for a 2016 exhibition, after he was named prosecutor-general. The case was eventually dropped.
 • He was accused of meddling in the 2020 general 
election by instigating the main opposition party to file complaints against ruling party leaders, but the case fizzled out.
 • Ms Kim was rumoured to have worked as a nightclub hostess before marriage – which she denied.
 • She was accused of falsifying her credentials to apply for teaching jobs. She admitted she exaggerated some details, such as claiming that she won the grand prize at the Seoul International Cartoon and Animation Festival in 2004.
 • She was allegedly involved in the manipulation of the stock price of car dealer Deutsch Motors from 2010 to 2011. 
 • Ms Kim’s mother was indicted in July on charges of fraud and medical law violations in relation to a nursing home in which she invested. She was sentenced to three years in jail. Last week, she received another one-year jail term for forging a financial document to buy land.

Mr Lee Jae-Myung and family

 • Mr Lee (left, seen here with his wife) was indicted in 2018 for abuse of power to confine his older brother to a psychiatric hospital, but was later acquitted.
 • He 
was rumoured to have had an affair with actress Kim Bu-seon, who confirmed it in 2018 and even filed a lawsuit against him for forcing her to lie.
 • His wife Kim Hye-gyeong allegedly spread 
misinformation about his political rivals. The case was handed to the prosecution in 2018 but was thrown out due to lack of evidence.
 • Mr Lee’s son was said to have gambled online illegally from 2019 until recently. He wrote a review about a massage parlour, raising suspicions that he went there for illegal sexual services.
 • As a lawyer, Mr Lee defended a nephew who stabbed his girlfriend and her mother to death in 2006. He was accused of downplaying the case as dating violence and wrongfully using mental illness as a defence.