The Supreme Court’s full bench on April 23 unusually scheduled the date of second session of deliberation at a rapid pace in the case of Lee Jae-myung, the Democratic Party of Korea's presidential front-runner, who is facing charges of violating the Public Official Election Act. If a ruling is issued before the early presidential election scheduled for June 3, it is expected to affect his political career in one way or another.

Lee, the party’s candidate in the 20th presidential election, was indicted for allegedly spreading false information related to suspicions involving the late Kim Moon-ki, former director at Seongnam Development Corporation, and allegations of preferential treatment in the rezoning of of the site of the Korea Food Research Institute in Baekhyeon-dong, Seongnam. In November last year, he was sentenced to one year in prison with a two-year suspended sentence by a district court, a ruling that would have disqualified him from running for public office for ten years. However, on March 26, the appellate court overturned the conviction and acquitted him, reviving his political prospects.

The key legal question between the first and second trials was whether Lee’s statement that he "did not know" Kim Moon-ki constituted a false claim under the election law. The appellate court ruled that the statement pertained to his “perception” rather than an “act,” and therefore could not be deemed criminal. The court also found that Lee’s remarks regarding the Baekhyeon-dong were expressions of opinion, not false statements.

The Supreme Court’s role in this case is limited to reviewing whether the lower courts applied the law correctly, without re-investigating the facts of the case, as the sentence is under 10 years. Therefore, starting with the second session, the Supreme Court is expected to focus on the interpretation of Lee's statements and whether they meet the threshold for criminal falsehoods under the election law. Lee’s defense team has already submitted a brief to the court arguing that “both lower courts had properly assessed the facts, and that the acquittal contains no legal errors, making the prosecution’s appeal inappropriate.”

The Supreme Court is expected to reach one of three major outcomes, which are dismissing the appeal and confirming the acquittal, overturning the appellate court’s ruling and sending the case back for retrial, and suspending the trial altogether.

If the appeal is dismissed, Lee will gain momentum in the presidential election campaign. However, if the acquittal is overturned, he will continue to face legal uncertainty. Even if he wins the election, he will face controversy if the Supreme Court upholds his sentence of more than 1 million won in fines and disqualification to run for an election.

Legal experts believe that the Supreme Court will likely settle the issue in some way before the presidential election, given the fact that its full bench scheduled the additional date of the second session of deliberation. If the full bench is unable to reach a consensus and sentence Lee before the election, there is also the possibility of a “stay of proceedings” to decide how to proceed. It is up to the Supreme Court to decide whether Article 84 of the Constitution, which specifies the president's immunity from prosecution, includes only “prosecution” or also includes “trial” already underway.

Professor Hong Sung-soo of Sookmyung Women's University’s Law Department said, “Even if the Supreme Court rushes a decision before the election, it may face accusations of ‘political interference.’ But going further than that seems highly unlikely. Removing a leading presidential candidate in this manner would place enormous pressure on the court.”

In theory, the Supreme Court could both overturn the ruling and determine the sentence itself, a process known as "reversal and self-rendering of judgement.” But such an outcome is extremely rare, as the Supreme Court is a court of law and has no precedent for reviewing sentences in cases that have been acquitted on appeal.