The Seoul Central District Court found Yoon and his ex-defence minister, Kim Yong Hyun, guilty of aiding an adversary and abusing their power, saying they sought to provoke North Korea into launching armed attacks or other serious provocations against South Korea to manufacture a national emergency.
It said the moves harmed South Korea’s military interests by exposing its capabilities, undermining its ability to conduct future operations and prompting North Korea to strengthen its defence posture.
The same court earlier sentenced Yoon to life in prison for a rebellion conviction over his short-lived imposition of martial law in December 2024.
North Korea accused Seoul of flying drones over Pyongyang to drop propaganda leaflets three times in October 2024. Kim, who was South Korea’s defence minister at the time, issued a vague denial before the Defence Ministry said it could neither confirm nor deny the allegations. Tensions rose sharply but did not lead to any military clashes.
Yoon’s lawyers criticised the latest ruling, saying the drone flights were a response to North Korea flying thousands of trash-carrying balloons into the South earlier in 2024. They argued that a guilty verdict would undermine South Korea’s security interests but did not immediately say whether they would appeal.
Investigators led by special prosecutor Cho Eun-suk had sought a 30-year prison term for Yoon, accusing him of trying to create a warlike situation between the Koreas while plotting an authoritarian push to remove his political opponents and “monopolise” power. They had sought a 25-year prison term for Kim Yong Hyun, a key confidant of Yoon who helped plan and mobilise forces for Yoon’s martial law declaration.
Yoon proceeded with the declaration late in the night of Dec. 3, 2024, delivering a televised address in which he accused liberal lawmakers of being North Korea-sympathising “anti-state” forces. He cited a range of grievances, but particularly the opposition’s impeachments of senior officials and cuts to his government’s budget bill.
Martial law lasted about six hours until lawmakers broke through a blockade of soldiers and police at the National Assembly and voted to overturn it, forcing Yoon’s Cabinet to lift the measure.
Yoon was quickly suspended from office, impeached and formally removed by the Constitutional Court. He was arrested in July 2025 and several criminal trial are ongoing.
The verdict in the most serious case, of rebellion, has been appealed both by Yoon and prosecutors, who had sought a death sentence.
