Impeached president’s treason trial to start next week

Former President Yoon Suk Yeol attends his third impeachment hearing at the Constitutional Court in Jongno District, Seoul, Jan. 21. Joint Press Corps

The first criminal investigation into former President Yoon Suk Yeol on treason charges is set to begin next week, following the Constitutional Court’s impeachment decision on Friday.

Although constitutional and criminal trials are fundamentally different, the Constitutional Court’s ruling is likely to influence the criminal proceedings, as it acknowledged key facts — such as the declaration of martial law being unconstitutional and unlawful — which are central to the treason charge.

The Seoul Central District Court scheduled the first trial date for April 14, during which witness examinations are expected to begin. Prosecutors have requested Deputy Prime Minister and Finance Minister Choi Sang-mok, as well as Foreign Minister Cho Tae-yul, to appear as witnesses, although it remains unclear whether they will attend.

Yoon is required to attend the first hearing, as defendants are obligated to be present at trial hearings, unlike pretrial sessions. Additional hearings are expected on April 21, 28 and May 1.

The central issue in the upcoming criminal trial is whether Yoon's declaration of martial law was intended to subvert the Constitution, which is a key element in the charge of treason. This issue closely mirrors the one addressed in the constitutional trial.

Prosecutors argue that Yoon not only declared martial law in an unconstitutional and illegal manner but also attempted to block the National Assembly by mobilizing troops and police, which they claim was an effort to overthrow the constitutional order.

While upholding Yoon’s impeachment, the Constitutional Court acknowledged all five grounds for impeachment — the declaration of martial law, the deployment of military and police forces to the National Assembly, the issuance of emergency decrees, the attempted raid on the National Election Commission and efforts to track the whereabouts of legal professionals.

However, since the evidentiary standards are more stringent in a criminal trial than in an impeachment trial, testimony from key figures could become a crucial factor in determining the outcome.

The Seoul court will now determine whether these actions constitute treason and insurrection under criminal law, specifically if they were carried out with the intent to subvert the nation’s constitutional order.

Yoon’s attorneys are expected to argue in his upcoming trial that the martial law declaration was merely a symbolic warning or a political gesture, rather than an attempt to overthrow the constitutional system.

If found guilty of treason, Yoon could face the death penalty or life imprisonment.

Meanwhile, prosecutors are also likely to indict Yoon on additional charges, such as abuse of power. Further investigations into election interference, including allegations of manipulating the People Power Party’s candidate nominations for by-elections in 2022 and general elections in 2024, may also accelerate.