With President Yoon Suk Yeol seemingly edging toward impeachment, the nation is eyeing the next logical move of electing his replacement. Lee Jae-myung, leader of the main opposition Democratic Party of Korea, is the clear front-runner in that race, multiple polls suggest.

But the runner-up in the last presidential election by a tiny margin, Lee has his own legal challenges regarding another bid for the top office. He still faces criminal charges related to his respective terms as mayor of Seongnam, Gyeonggi Province, and governor of that province.

Lee is currently or has recently been the defendant in five trials.

In one trial, a district court acquitted him of suborning a mayoral official, while in another, he was handed a one-year prison sentence, suspended for two years, in an election law violation case. Both cases are headed for appellate trials.

South Korea's Public Official Election Act states that anyone who has been sentenced to at least 1 million won ($700) in fines is ineligible to be a public official.

If Lee is convicted and fined 1 million won or more in any of the ongoing trials, or if the suspended jail term he received in November is upheld by the Supreme Court, he will not even be able to throw his hat in the ring for the next presidential election.

Election timing critical

Lee's headaches might be a moot point if South Korea holds the next presidential election before the Supreme Court reaches a decision on any of his five trials.

The Constitution states in Article 84 that a sitting president is not to be charged with any criminal offense barring insurrection or treason -- the very charges the incumbent Yoon is currently facing.

But whether this means the ongoing trial of someone elected president should be paused upon that election is up for debate.

The Constitutional Court in November was faced with this very matter, and its official position was that "the matter should be decided after the court's review on a specific case." The court explained that the relevant legal provisions primarily concern the indictment of an incumbent president, and there is debate within legal circles about whether they apply to ongoing trials.

While the matter is not set in stone, Lee is widely expected to be protected by the law at least to some extent if he is elected president of the country.

This is why any attempt to move South Korea past the turmoil caused by martial law, by replacing its mastermind, President Yoon, with a new leader, is not so simple but rather complicated by political calculations along party lines.

A Media Research poll conducted on Sunday found that 52.4 percent of respondents chose Lee Jae-myung as the "most suitable candidate for the next president."

When would court bring hammer down on Lee?

Rumors of Lee's trials being delayed have been floating around political circles. Lee's five trials, indictment for which took place as early as September 2022 and as late as last month, have already taken longer than usual to reach a verdict.

The aforementioned November sentence for the election law violation case came over two years after indictment -- 799 days to be exact. The Public Official Election Act says that election law violation cases should be sentenced within six months of indictment, with the appellate ruling and Supreme Court ruling to each be concluded in subsequent three-month periods.

The clause is widely considered nonbinding and has often been ignored, particularly for defendants who lost their election. However, in July the Supreme Court urged justices across the country to adhere to the guideline.

Lee's particular case has been postponed multiple times due to him attending a parliamentary audit, as well as health issues such as a hunger strike and being infected with COVID-19.

If the court guidelines for the appellate and Supreme Court rulings are respected, final verdicts on Lee's charges could be expected as early as May 2026.

Parties tussle

Knowing this, of course, the goal of the ruling People Power Party is to avoid an early election at all costs.

Rep. Kim Sang-hoon, the top policymaker of the ruling party, said in a radio interview Tuesday that the process involved with Yoon's stepping down early "should not be conducted in accordance with the Democratic Party's intent, or with Lee's intent.”

"It is clear that the DP intends to hold the next presidential election before Lee loses candidacy (eligibility) due to trials he is facing, and we should respond accordingly.”

Kim said he is expecting Yoon to step down around May of next year, saying none of the party members are currently expecting the president to carry out his duties normally. Yoon's five-year term is due to end in May 2027.

The ruling party initially blocked Yoon's impeachment motion by boycotting the vote at the National Assembly on Saturday. But with the public demanding that Yoon step down and with his popularity at an all-time low, the People Power Party is facing an uphill battle to extend the president's time in the office.

Reports indicate that unknown members of the ruling party have switched their positions on Yoon’s impeachment, although exactly how many remains unclear.