A South Korean appeals court has reduced the prison sentence of former Prime Minister Han Duck-soo from 23 years to 15 years, in a case stemming from his role in ex-President Yoon Suk Yeol's brief declaration of martial law in December 2024. The Seoul High Court handed down the revised sentence on Thursday, with the presiding judge announcing: "We sentence the defendant to 15 years in prison."

Yoon's martial law decree suspended civilian rule for roughly six hours before opposition lawmakers convened an emergency session and voted to overturn it. The episode plunged South Korea into its worst political crisis in decades. A lower court in January had sentenced Han — then seen as a heavier-than-expected penalty — to 23 years for his role in the insurrection, as well as on related charges of perjury and falsifying an official document. The appeals court upheld most of his convictions but acquitted him on one perjury count concerning whether he had witnessed a document being passed between two senior officials.

In explaining the reduced sentence, the presiding judge cited Han's "more than 50 years as a public official prior to the martial law declaration" and acknowledged that the evidence did not clearly show he had conspired in advance or actively led the operation. Nevertheless, the judge found that Han had "abandoned the grave responsibilities arising from the authority and position entrusted to him and instead sided with those participating in the acts of insurrection." The court also noted that Han had lived through South Korea's authoritarian era in the 1970s and 1980s and was therefore well aware of the damage unconstitutional martial law could cause. Han, 76, listened to the verdict in a white shirt and dark suit with no tie, showing little emotion. His lawyers announced they would appeal to the Supreme Court.

Han is an experienced technocrat who served in senior government positions under five presidents, including as finance minister. After Yoon was impeached, Han became acting president — before being impeached himself on accusations of having aided Yoon. The Constitutional Court later overturned Han's impeachment, restoring his powers briefly before he resigned to run in a snap presidential election in June, a bid he abandoned amid rifts among conservatives. Yoon, who faces eight separate trials, was sentenced to life imprisonment in February for masterminding the insurrection. In a related development last week, an appeals court increased Yoon's sentence for obstructing justice to seven years, and his wife, former first lady Kim Keon Hee, saw her separate corruption sentence raised to four years on appeal.

Thursday's ruling is the latest in a string of appeal verdicts working their way through South Korean courts following the martial law crisis. The outcome matters because it signals how the judiciary is weighing individual culpability among the senior officials swept up in events that briefly threatened one of Asia's most stable democracies. Han's legal battle is set to continue at the Supreme Court, prolonging a case that has already reshaped South Korean politics.