A sitting president declared martial law, lost it within hours, was impeached, removed by a unanimous court, and sentenced to life for insurrection — then to 30 more years for treason. Here is the whole story, in order.
At around 10:27 p.m. on December 3, 2024, Yoon announced emergency martial law in a televised address — the first such declaration since 1980 and the first of South Korea's democratic era. A martial law command banned political activity and moved to control the press. Troops were deployed to the National Assembly and, in an unprecedented step, to the building of the National Election Commission (NEC).
The response was immediate. Lawmakers — some climbing over fences past soldiers — gathered in the main chamber. At about 1:02 a.m. on December 4, with 190 members present, all 190 voted to lift martial law (190–0). Under the Constitution, the president must comply, and Yoon rescinded the decree later that morning. The entire episode lasted roughly six hours.
Political consequences came quickly. On December 14, 2024, the National Assembly voted to impeach Yoon, immediately suspending his presidential powers and sending the case to the Constitutional Court. On April 4, 2025, the court unanimously (8–0) removed Yoon from office, making him the second South Korean president ever removed by the court (after Park Geun-hye in 2017). His removal triggered an early presidential election, which Lee Jae-myung won; Lee took office in June 2025.
Removal from office is a constitutional remedy; criminal liability is separate. Prosecutors charged Yoon as the ringleader of an insurrection. On February 19, 2026, a first-instance court sentenced him to life imprisonment. The appeal was later suspended after Yoon's side filed a motion to recuse the appellate panel, which is being litigated. Several co-defendants, including former defense minister Kim Yong-hyun, face their own proceedings.
A separate case widened the scope. Prosecutors alleged that, before the martial law declaration, a covert military drone operation was directed toward North Korea — an attempt, they argued, to provoke Pyongyang and manufacture a pretext (a "northern wind") for declaring martial law. On June 12, 2026, a first-instance court found Yoon guilty of general treason (a category under the criminal code's offenses against the state) and sentenced him to 30 years. Kim Yong-hyun also received 30 years, and a key commander, Yeo In-hyung, received 15 years. It was the first time a former South Korean president was convicted of treason.
The crisis drew intense international coverage — from the New York Times to the BBC and Reuters — partly because South Korea is a major U.S. ally and a leading democracy, and partly for the sheer speed of the reversal. Within hours, an elected legislature had overturned a martial law decree on live television; within months, an independent court had removed the president. Many observers framed the episode as a stress test that the country's institutions ultimately passed, even as it exposed how close the system came to a graver outcome. Domestically, polling showed strong majorities supporting both the impeachment and the court's decision, though the country remained politically divided.
As of mid-2026, the constitutional questions are settled — Yoon is out of office, and Lee Jae-myung is president — but the criminal questions are not. The insurrection appeal is entangled in procedural disputes, and the treason verdict can be appealed up to the Supreme Court. In short: the political crisis is over; the legal reckoning is still unfolding.