Former South Korean President Yoon Suk Yeol faces life in prison after being found guilty of leading an insurrection with his 2024 martial law declaration, a move that shocked the nation and triggered the country’s most severe political crisis in decades.

Yoon and other defendants, including his former defense minister, undermined the core values of democracy by trying to paralyze the National Assembly, the Seoul Central District Court said, handing down the verdict on Thursday.

The court delivered a life sentence for Yoon. Prosecutors had sought the death penalty on grounds that he posed a grave threat to the country’s constitutional order. Yoon’s former defense minister, Kim Yong-hyun, was sentenced to 30 years in prison.

“The social costs stemming from the martial law declaration are incalculable,” the court said. “Our society became politically polarized, experiencing extreme confrontation.”

Yoon’s lawyers denounced the ruling as politically motivated and vowed to “fight until the end.” One of the lawyers said the legal team will discuss with Yoon whether to appeal the ruling. Any appeal would proceed to a higher court and could take months to resolve.

The verdict comes in one of the most consequential judicial proceedings involving a former South Korean president, with the martial law episode garnering attention as a test of the country’s democratic health. The incident dredged up memories of former leader Chun Doo-Hwan, who was sentenced to death over an attempted coup in the late 1970s. Chun was ultimately pardoned.

Yoon, 65, was indicted last year on charges of insurrection after suspending civilian rule in the previous December. The short-lived decree led to his impeachment and the first arrest and indictment of a sitting South Korean president.

The former leader has denied any wrongdoing, saying his declaration was a desperate bid to counter what he claimed were North Korea sympathizers trying to paralyze his administration. At the final hearing in January, he said public opposition to his impeachment made him feel the “emergency alarm” he sounded had been effective.

Yoon, clad in a navy jacket, quietly sat and listened to the judge during the hour-long session. Some of his supporters shouted “Yoon again!” as he left the courtroom.

A former top prosecutor, Yoon rose to the presidency promising to revive a Covid-hit economy and take a more hawkish stance on North Korea and China. But without a majority in the National Assembly, the legislative process became gridlocked. His political gamble upended his administration, ending his tenure and paving the way for elections. The more progressive President Lee Jae Myung swept to power in June.

The verdict may give Lee more scope to push through his policy agenda as the main opposition People Power Party grapples with the latest fallout from the martial law fiasco amid an ongoing struggle to reinvent itself. Still, Lee needs bipartisan support as he tries to heal a divided nation and protect the export-reliant economy from President Donald Trump’s tariff pressure.

After the sentence was handed down, ruling Democratic Party lawmakers criticized the court for being too lenient. Meanwhile, Song Eon-seok, the floor leader of Yoon’s People Power Party, issued an apology, vowing to sever ties with any factions that threaten the country’s constitutional order.

Analysts point to the verdict and sentence demonstrating that South Korea has the institutions in place to protect its democracy.

Still, the ruling also fits in with a pattern of South Korean presidents ending their careers in disgrace in a cycle that keeps the nation’s political environment highly polarized.

Leif-Eric Easley, a professor at Ewha University in Seoul, says political parties have room to improve in putting partisanship aside and building a more effective, well-functioning legislature.

“Ultimately, Koreans want and deserve a democracy where their leaders need not be impeached, removed, prosecuted, and sentenced to life in prison,” he said.

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—With assistance from Shinhye Kang, Seyoon Kim, Brian Fowler, Cat Barton and Hyonhee Shin.

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