Lee Jae-myung, chair of the main opposition Democratic Party of Korea, holds up a placard during a mass rally in central Seoul, Nov. 23, demanding an independent counsel investigation into allegations involving first lady Kim Keon Hee. Yonhap

Opposition leader Lee Jae-myung is set to be sentenced Monday on charges of suborning a former mayoral secretary to make false court testimony in his favor, the second in a series of rulings that threaten to shut him out of a future presidential run.

Lee, the leader of the main opposition Democratic Party of Korea, is accused of suborning a secretary to former Seongnam Mayor Kim Byung-ryang to give false testimony during a 2019 trial on his alleged election law violations.

The alleged offense took place when Lee, as a candidate for Gyeonggi governor, told a TV debate in 2018 that he had been wrongly convicted in the early 2000s of impersonating a prosecutor in front of the Seongnam mayor in order to gather information on an apartment project scandal in collusion with a KBS TV news producer.

Lee was acquitted in the election law violation case, which prosecutors suspect was helped in part by the secretary's false testimony.

According to prosecutors, Lee suborned the secretary to testify that he was framed by the former mayor and KBS. Lee has denied the charge, claiming he only asked the secretary to testify truthfully.

The Seoul Central District Court is set to deliver its sentence at 2 p.m.

Should he be sentenced to a prison term and the ruling is upheld, Lee will be stripped of his parliamentary seat and barred from running for public office for at least five years after serving his term, which includes the next presidential election in 2027.

In the event he is sentenced to a suspended prison term, Lee will also lose his parliamentary seat but be barred from running in elections only until the end of the suspension period, which could still allow him to run in the next presidential election.

If sentenced to a fine, however, Lee will neither lose his parliamentary seat nor be barred from running for office.

Prosecutors have demanded a three-year prison term for Lee.

The opposition leader is also standing trial in four other cases.

In the first ruling earlier this month, he was sentenced to a suspended one-year prison term for violating election laws by making false statements as a candidate during the previous presidential election.

Lee has widely been considered a front-runner in the next election after having lost to President Yoon Suk Yeol by 0.73 percentage point in 2022. (Yonhap)