Main opposition Democratic Party of Korea leader Rep. Lee Jae-myung leaves the Seoul Central District Court, Friday, after being sentenced to one year in prison, suspended for two years on charges of violating election law. Yonhap

Main opposition Democratic Party of Korea (DPK) Chairman Rep. Lee Jae-myung is facing the biggest crisis in his political career after a local court sentenced him to one year in prison, suspended for two years, Friday, on charges of violating the election law, according to political watchers.

The Seoul Central District Court delivered its verdict on charges that Lee allegedly violated the Public Official Election Act by making false claims about a land development project pursued by the Seongnam government during his term as the city's mayor.

If any prison sentence or fine exceeding one million won ($713) is finalized, Lee would be stripped of his parliamentary seat and barred from running for public office for the next five years, including the 2027 presidential election. Lee, who narrowly lost to President Yoon Suk Yeol in the 2022 presidential election, is considered a key contender for the 2027 election.

The DPK needs to return the 43.4 billion won it received from the National Election Commission to cover its presidential election expenses.

Experts said Friday's verdict won't have an immediate impact on the DPK, although it will likely lead the ruling People Power Party (PPP) to intensify its political attacks on Lee.

"This marks the first decision in Lee's four ongoing criminal cases. For the DPK, the Nov. 25 ruling on charges of perjury is more important. However, today's result may prompt the DPK to start discussion of a Plan B for their presidential nominee for 2027 presidential election. The change will likely be visible after 2026 local elections," Eom Gyeong-yeong, director of political think tank the Zeitgeist Institute, said.

"The PPP will likely escalate political attacks against Lee, but that wouldn't necessarily lead to a rise in the ruling party's approval rating. However, it could resolve conflict between the pro-Yoon faction and pro-Han faction within the party," Eom added.

The PPP called on Lee and the DPK to humbly accept the ruling.

"The court decision was made solely on the basis of evidence and legal principles. Lee and the DPK should humbly accept the ruling and apologize for their misdeeds," PPP spokesperson Rep. Kwak Kyu-taek said.

The minor opposition Rebuilding Korea Party expressed strong regret over the harsh ruling on the opposition leader.

The opposition leader said he would appeal the court's decision. "It's impossible to accept this conclusion. I will appeal," he said.

Supporters of Democratic Party of Korea (DPK) Chairman Rep. Lee Jae-myung hold banners that read "Lee Jae-myung is innocent" in front of the Seoul Central District Court in Seoul, Friday. Yonhap

Lee was found guilty of making false statements during a parliamentary audit of the Gyeonggi Provincial Government in October 2021. He had claimed that he changed the zoning status of the former site of the Korea Food Research Institute in Baekhyeon-dong, Seongnam, due to pressure from the Ministry of Land, Infrastructure, and Transport.

However, allegations were raised that Lee gave preferential treatment to private developers and caused losses to the city government. Prosecutors had sought a two-year prison term for Lee.

The court, however, ruled that Lee was not guilty of the accusation that he lied during a media interview in December 2021, in which he claimed not to know the late Kim Moon-ki, former head of the development division at Seongnam Development Corp., which was involved in a corruption-ridden development project in Seongnam.

Lee is currently standing trial in three other cases: charges of suborning a former mayoral secretary to provide false testimony in his favor, corruption related to the Seongnam development project, and involvement in an illegal cash transfer of $8 million to North Korea.

Meanwhile, Lee's wife Kim Hye-kyung was sentenced to a fine of 1.5 million won for allegedly misusing a government credit card for personal use spending 104,000 won on dining in restaurants, during Lee's time as Gyeonggi governor from 2018 to 2021.