It remains uncertain what led Yoon to resort to such a decades-old measure - the declaration of martial law - early this month, a move that could be seen as characteristic of an authoritarian regime, despite his implausible explanations of eliminating "pro-North Korean forces" and protecting South Korea's "constitutional order."
With a parliamentary vote to impeach him passed on Saturday, Yoon's duties as president were immediately suspended less than two weeks after his aborted Dec. 3 martial law gambit.
But his impeachment brings political uncertainty, creating a power vacuum until the Constitutional Court makes its decision after deliberating the case, which may take several months. Once upheld, he would become the second South Korean president to be impeached, following former disgraced President Park Geun-hye, which would require a presidential election within 60 days.
Now, attention shifts to potential candidates in the upcoming presidential election, which is likely to be held in the spring of next year.
Among them, Lee Jae-myung, leader of the main opposition Democratic Party (DP), is currently considered one of the frontrunners in the presidential race.
In a recent survey of over 1,000 voters conducted by pollster Embrain Public earlier this week, about 37 percent of respondents supported Lee, while a mere seven percent favored Han Dong-hoon, leader of the ruling People Power Party (PPP). The survey also found that nearly half of the respondents supported the DP, compared to just 21 percent for the PPP.
Nevertheless, Lee's path to the top office is unlikely to be easy, as he remains entangled in multiple legal battles and plagued by a massive real estate scandal in addition to his own controversies including allegations of corruption and embezzlement.
Known as a tough-talking liberal, Lee is famous for his self-made success story. He grew up in a poor family in a rural town in Andong, North Gyeongsang Province, working as a factory worker, which left him with a disability in his arm. But he later paved his own way through school, passing the country's notoriously difficult bar exam to become a human rights lawyer.
Focusing on labor and human rights issues, he established himself as an advocate for workers, which led him into politics.
He served as the mayor of Seongnam, a city in Gyeonggi Province, before becoming the governor of the province surrounding Seoul in 2018, during which he built his strong support base with some populist policies.
During the 2022 presidential campaign, in which he lost to Yoon by the slimmest margin of 0.73 percentage points, Lee vowed to tackle economic polarization and eradicate inequality and unfairness by proposing a so-called "universal basic income" for low-income earners.
Previously a political outsider, Lee quickly demonstrated leadership and solidified his position as the leader of the DP in a short period of time, making him to be one of the most favorite presidential candidates within the DP.
But it remains to be seen if he will be cleared of all the allegations against him. In his first ruling last month, among several charges he faces, Lee was sentenced to a suspended one-year jail term for violating election laws, followed by being cleared of other charges in a separate case about two weeks later.
Lee insists he is innocent of all charges and accuses prosecutors of launching a politically motivated investigation.
But if any of his upcoming trials result in a fine of over one million won or a prison sentence by the upper courts, Lee would be stripped of his parliamentary seat and barred from running in the presidential election for the next ten years, casting a shadow over his political future.