At the start of business on Friday, an institution that had existed since 1948 ceased to be. South Korea's Supreme Prosecutors' Office was abolished after 78 years, replaced by two new bodies that split what one office used to do: investigate crimes and decide whom to charge.

It is among the most sweeping changes to the country's criminal justice system in decades, according to the Korea Times. It also arrived with an awkward fact attached: the president who pushed it through has criminal cases of his own that prosecutors brought.

What Changed on Oct. 2

Under the new system, a restructured Prosecution Service handles indictments and courtroom prosecution only, the Korea Herald reported via Yonhap. A new Serious Crimes Investigation Agency, known in Korean as Jungsucheong, runs investigations into seven categories of crime, including corruption, defense industry offenses, insurrection and national security cases, according to Bloomberg. The police and the Corruption Investigation Office for High-ranking Officials take most of the rest.

Prosecutors lose the power to run supplementary investigations. Seoul Economic Daily reported that 42 direct investigation divisions at prosecutors' offices were abolished and converted into 29 serious-crime indictment divisions. Cases already underway get a 90-day grace period before they must be transferred to the police or the new agency.

Why Lee Wanted It

President Lee Jae-myung frames the change as protection against politicized prosecutions. "I have been, still am, and will continue to be one of those who have suffered the most from the prosecutors' abuses," Lee has said, according to Bloomberg, and he has vowed to make the reform irreversible.

History gives his argument force. Bloomberg counted that of the eight presidents who served before Lee since direct elections began in 1987, four were imprisoned, ousted or both after investigations by prosecutors. Lee's own rise followed the martial law crisis triggered by his predecessor Yoon Suk-yeol, himself a former top prosecutor.

The timing is awkward for the same reason. Lee's trials, over accusations involving private land developers, misuse of public funds and election law, are suspended while he is president. He denies wrongdoing and calls the indictments politically motivated.

A Launch Short on Almost Everything

The new investigation agency opened understaffed. Yonhap reported it started with about 1,900 employees, roughly 66% of its authorized 2,874. The Herald Business reported days before launch that staff transferring in did not know their assignments, the agency's offices lacked basic infrastructure, and its inaugural director was absent at launch.

Day one was messy. Seoul Economic Daily reported trial delays, system failures and a dispute over the legal status of prosecutors seconded to special counsel teams. Regional investigation offices were short on buildings and computer systems.

Some of this is the ordinary friction of building an institution in a hurry. The part that matters is the 90-day clock: if the transfer of cases stalls, victims and defendants in the middle of ongoing investigations are the ones who wait.

The Appointment Fight

The choice of leader exposed a split in Lee's own camp. The Korea Herald reported that Lee pressed ahead with Kim Ji-yong, a career prosecutor, as the agency's first head, despite opposition from within the ruling party and the broader progressive bloc. Hard-liners argued a former prosecutor should not lead an agency meant to end prosecutorial dominance.

A presidential official defended the pick, arguing that excluding Kim only because of his background would defeat the purpose of the selection process and ignore the need for investigative expertise. Both points have merit. A reform meant to break a corporate culture may need people who know how that culture works, and the credibility of the agency will depend on whether it can investigate powerful figures on all sides.

The Public Is Not Sold

Voters have not warmed to the overhaul. A Gallup Korea poll in August found half of respondents against the reform and 27% in favor, Bloomberg reported. Lee's approval rating now hovers below 40% with nearly four years left in his single five-year term, and the reform is seen as one factor.

Critics raise two concerns. One is that giving the police wider investigative power with fewer checks could produce its own abuses. The other is whether prosecutors can build sound indictments without any investigative authority, according to the Korea Herald. Bloomberg noted worries about gaps that could leave crime victims worse off, and about disputes over which agency has jurisdiction.

What to Watch Next

The first high-profile corruption or political case that goes to the new agency will be the real test. If it pursues officials in the government camp as readily as the opposition, the argument that this is institutional reform and not a favor to the president will be much stronger.

Prosecuting former leaders is a live question well beyond Seoul. In Brazil, which votes on Sunday, the shadow of an imprisoned former president hangs over the campaign. In both countries, the same lesson applies: the independence of those who investigate and charge leaders matters more than the structure on the organization chart.