South Korean opposition leader Lee Jae-myung was convicted on Friday of violating election law and given a suspended prison sentence by a court that ruled he made false statements while denying corruption allegations during a presidential campaign.

If upheld, the ruling could significantly shake up the country’s politics, potentially ousting Lee as a lawmaker and denying him the chance to run for president in the next election. But Lee, who faces three other trials on corruption and other criminal charges, is expected to challenge any guilty verdict and it remains unclear whether the Supreme Court will rule on any of the cases before the March 2027 presidential vote.

Lee told reporters he plans to appeal Friday’s verdict at the Seoul Central District Court, which handed him a one-year prison sentence suspended for two years. Under South Korean law, Lee would lose his legislative mandate and be barred from running for election for five years if he receives either a penalty exceeding a 1 million won ($750) fine for violating the election law or any imprisonment for other offences.

“There are still two courts left in the real world, and the courts of public opinion and history are eternal,” he said, apparently referring to plans to take the case to the Supreme Court. “This is an impossible conclusion to accept.”

Lee, a liberal who narrowly lost the 2022 election to conservative President Yoon Suk Yeol, has strongly denied wrongdoing.

The ruling from the Seoul Central District Court attracted intense media coverage and apparently thousands of protesters. Surrounded by police lines, Lee’s supporters and critics occupied separate streets near the courthouse, shouting opposing slogans and holding signs reading “Lee Jae-myung is innocent” and “Arrest Lee Jae-myung.” There were no immediate reports of major clashes.

Prosecutors indicted Lee in 2022 on allegations he made false claims related to two controversial development projects in the city of Seongnam, where he served as mayor from 2010 to 2018 while campaigning as a presidential candidate for Democratic Party.

One of the comments cited by prosecutors is related to suspicions that the city of Seongnam in 2015 changed the land use designation to allow a housing project on a site previously preserved as green space due to lobbying by private developers.

Lee said during a parliamentary hearing in October 2021 that the city was instead “forced” by the national government to make the site change from Baekhyeon-dong district. Prosecutors say there is no evidence to support Lee’s claim, which has been dismissed by the Ministry of Lands, Infrastructure and Transport.

Prosecutors also cited a TV interview Lee gave in December 2021, when he said he did not know a senior official from Seongnam’s urban development department during his time as mayor. Lee spoke a day after the official was found dead amid an investigation into a real estate development project in Daejang-dong district that reaped huge profits for a small asset management firm and its affiliates and raised suspicions of regarding possible corrupt links between them, city. officials and politicians.

Prosecutors argued that Lee lied to the public to distance himself from controversy and improve his chances of winning the election. They asked for a two-year prison sentence for him.

The court found Lee guilty of comments related to the Baekhyeon-dong project, saying it was clear that the city’s decision to change the land use designation of the site was not based on requests from the land ministry.