South Korea's ousted president Yoon Suk Yeol has been sentenced to life in prison for insurrection

A South Korean court on Thursday sentenced former president Yoon Suk Yeol to life in prison for leading an insurrection, finding that his brief but explosive declaration of martial law in December 2024 constituted a deliberate attempt to subvert the constitutional order of one of Asia’s most established democracies.

Presiding judge Ji Gwi-yeon, speaking for a three-judge panel at Seoul Central District Court, told a packed courtroom that Yoon deployed armed troops to the National Assembly with the explicit intention of paralysing the legislature. “The court finds that the intention was to paralyse the assembly for a considerable period,” the judge said, according to reporting from The Punch. “The declaration of martial law resulted in enormous social costs, and it is difficult to find any indication that the defendant has expressed remorse for that.”

Prosecutors had sought the death penalty. The life sentence — the maximum alternative under South Korean law for insurrection — ensures that Yoon, now 65, will spend the rest of his life behind bars barring a successful appeal or future pardon. Most inmates serving life terms in South Korea can typically apply for parole after 20 years, as RTÉ reported.

A six-hour crisis that upended a democracy

The conviction stems from the night of 3 December 2024, when Yoon appeared on national television shortly before 10:30 p.m. local time to announce the imposition of martial law, declaring it necessary to root out “anti-state forces” and overcome political deadlock with the opposition-controlled parliament.

What followed was a chaotic sequence of events that tested the structural resilience of South Korean democracy. Within an hour of the declaration, a military decree banned all activity by political parties and lawmakers. Troops and special operations soldiers descended on parliament, where staffers resorted to barricades and fire extinguishers to prevent entry. Lawmakers scaled fences to evade security cordons as protesters gathered outside.

By the early hours of 4 December, 190 lawmakers had assembled inside the chamber and voted unanimously to reject the martial law declaration. Troops began withdrawing. Roughly three and a half hours later, Yoon lifted the decree. The entire episode lasted approximately six hours.

But the political aftershock was seismic. On 14 December, parliament impeached Yoon with the backing of 204 of its 300 members, including at least 12 from his own ruling People Power Party. His presidential powers were suspended. A protracted standoff over his arrest followed — authorities initially failed to detain him during clashes with presidential security inside his compound in early January 2025 — before Yoon finally surrendered on 15 January.

The fall of a prosecutor-turned-president

The life sentence marks a staggering reversal for a man whose career was built on the exercise of legal authority. Yoon spent decades as one of South Korea’s most prominent prosecutors, investigating two sitting presidents and building a reputation as a fearless — some said reckless — legal combatant.

“Yoon Suk Yeol was the most powerful prosecutor-general ever,” said Han Dong-soo, a former judge who headed internal inspection at the prosecutors’ office under Yoon, as reported by The Star Online. “He used the office to carry out his plan to become president and in doing so, his actions were daring.”

There were warning signs, colleagues now say with the clarity of hindsight. Han recalls a dinner in 2020 at which Yoon, then a powerful prosecutor, declared: “If I had gone to the military academy, I would have staged a coup.” The remark, made over free-flowing drinks, was treated at the time as bravado. It now reads as something closer to prophecy.

Yoon entered politics only a year before winning the presidency in 2022, propelled by conservative voters frustrated with the liberal policies of his predecessor, Moon Jae-in. Once in office, he became increasingly embattled by confrontations with the opposition-controlled legislature. A former prosecution rival, Lee Sung-yoon, told Reuters that the political warfare drew out a recklessness that had long been Yoon’s defining trait.

Seven co-defendants, a nation divided

Yoon was not sentenced alone. Former defence minister Kim Yong-hyun, who was arrested days after the martial law attempt, received a 30-year prison term for his role in the crisis. Former top police officials were also convicted. Kim’s lawyer confirmed the former minister would appeal, as The Irish Times reported.

Judge Ji noted that Yoon led multiple officials and troops in criminal activities on the night of 3 December, and that “sending armed troops to parliament and using equipment to try to make arrests all constitute acts of insurrection.”

Yoon stood ashen-faced and noticeably slimmer than at the time of his arrest, wearing a dark navy suit without a tie. He has been held in solitary confinement at the Seoul Detention Centre while fighting multiple criminal trials. He has consistently denied wrongdoing, arguing that his declaration of martial law was within presidential authority and was intended to “safeguard freedom” against what he characterised as an opposition-led “legislative dictatorship.”

His defence lawyer, Yoon Gap-geun, told reporters that the verdict appeared to be a “pre-determined conclusion set by the prosecutors” and that the court had “completely ignored the key legal principle of basing findings on evidence.” The defence team said it would consult with the former president on whether to file an appeal. Under South Korean law, a notice of appeal must be submitted within seven days.

Echoes of a darker era

Outside the courthouse, thousands of Yoon’s supporters gathered with placards reading “Yoon Great Again” and “Drop the charge against President Yoon.” Loud cries erupted as a blue prison bus believed to be carrying the former president entered the court complex. Police in neon-coloured jackets formed a makeshift barricade with buses parked nose-to-tail around the building.

The scenes underscored the depth of political division in a country that has long been regarded as a beacon of democratic stability in East Asia. Yoon’s failed power grab stirred memories of the military coups that convulsed South Korea between 1960 and 1980 — a period when authoritarian rule was imposed through precisely the kind of military force Yoon attempted to marshal.

South Korea has not executed a prisoner since 1997, maintaining an unofficial moratorium on capital punishment, though the last death sentence was handed down as recently as 2016. The prosecutors’ request for execution was therefore largely symbolic — but the symbolism mattered. It signalled the gravity with which the state treated the breach of democratic norms.

What the verdict reveals about democratic resilience

The structural significance of Thursday’s ruling extends beyond one man’s punishment. It confirms that South Korea’s democratic institutions — the legislature that voted down martial law within hours, the judiciary that convicted a former head of state, the prosecution service that sought the maximum penalty — held firm under extraordinary pressure.

The martial law episode lasted only six hours. The political and legal reckoning has now consumed more than fourteen months, sweeping in acting presidents, constitutional court proceedings, and multiple criminal trials. The process has been messy, contested, and at times chaotic — but it has operated within constitutional bounds.

Whether Yoon appeals, and how the appellate courts respond, will shape the next chapter of this crisis. Judicial guidelines stipulate that the entire process, including appeals, should conclude within two years. For now, the former prosecutor who once wielded the law as a weapon of ambition will remain in the detention centre where he has spent the past year — subject to the very system he once commanded.