South Korean president risks life in prison or death penalty if guilty of treason

South Korea's President Yoon Suk-yeol has replaced Defence Minister Kim Yong-hyun amid efforts by opposition parties to impeach both men over a brief period of martial law, which was later overturned by parliament.

Minister Kim offered his resignation and apologised for the disruption and concern caused to the public, admitting that troops acted under his orders and taking full responsibility for the incident.

On Thursday, President Yoon announced that retired General Choi Byung-hyuk, currently South Korea's ambassador to Saudi Arabia, would take over as defence minister. Until Choi assumes the role after a parliamentary hearing, Vice Defence Minister Kim Seon-ho will serve as acting minister. The hearing is largely symbolic, as the president can appoint ministers without requiring parliamentary approval.

A joint motion to impeach President Yoon has been submitted to the National Assembly and will be voted on Saturday evening.

Meanwhile, large crowds gathered outside the parliament, holding a candlelit vigil in protest against the president. Yoon, who faces potential prosecution for high treason, has not appeared in public since announcing the lifting of martial law on television.

Opposition lawmakers also voted on Thursday to impeach the chairman of South Korea's auditing board and three senior prosecutors. The prosecutors are accused of watering down an investigation into suspected stock manipulation involving Yoon’s wife.

Reactions from neighbours

Reactions from neighbouring countries varied following developments in South Korea. Chinese Foreign Minister Wang Yi declined to comment, saying that the situation was Seoul’s “domestic affair.”

On the other hand, the Japanese government said it was closely monitoring the situation in Seoul with serious concerns.

Chief Cabinet Secretary Hayashi Yoshimasa told reporters on Thursday that Japan and South Korea are important neighbours who should cooperate on global challenges. "The government will make appropriate decisions on the countries' comprehensive bilateral relations," Hayashi added.

Amid worries over the impact of Yoon’s declaration on South Korea’s democratic status, officials have been trying to mitigate backlash.

Foreign Ministry spokesperson Lee Jaewoong said the ministry sent diplomatic notes to foreign missions, stressing that martial law was lifted through democratic procedures and that travel advisories need not change, as public safety remains stable. Yoon’s declaration of martial law came just hours after his summit with Kyrgyzstan President Sadyr Japarov, who was in Seoul for an official visit. Meanwhile, Swedish Prime Minister Ulf Kristersson reportedly cancelled his planned trip to South Korea this week.

How do the numbers play out?

Impeaching the president would require the support of at least 200 members in South Korea’s 300-seat National Assembly, a two-thirds majority.

The opposition parties currently hold 192 seats and would need backing from 18 lawmakers within Yoon’s party. However, members of the anti-Yoon faction in his party, despite labelling his declaration of martial law “unconstitutional,” have stated they will oppose impeachment.

If the impeachment proceeds, Yoon would be suspended from office while the Constitutional Court decides whether to remove him permanently.

The impeachment motion accuses Yoon of failing to meet the constitutional conditions for declaring martial law, which is restricted to wartime or similarly severe crises.

It claims he attempted a “self-coup” by mobilising the military, suspending political party activities, and using troops to block access to the National Assembly — actions deemed tantamount to rebellion.

However, since the Korean War has never officially ended, Yoon might argue that South Korea remains in a state of war, providing a legal basis for his actions.

High treason is punishable by death under South Korean law.

Although the death penalty remains legal, no executions have been carried out in the country since 1997.