The governing center-left party of South Korea scored a sweeping victory in local elections on Wednesday but suffered a stinging setback in the capital, Seoul, losing the race for the city’s mayor, which is considered the most powerful elected office after the presidency.
Pre-election surveys and exit polls had consistently predicted that the candidate from President Lee Jae Myung’s Democratic Party would defeat the incumbent in Seoul, a conservative. The party, which already holds a parliamentary majority, had hoped to use the local elections to consolidate its influence and extend Mr. Lee’s political momentum, a year after his presidential victory.
“Seoul citizens have once again firmly established the fundamental principle of democracy: checks and balances,” Oh Se-hoon, who was re-elected mayor of Seoul, said on Thursday. “You have kept Seoul as the final safeguard of democracy, ensuring that South Korea does not tilt entirely to one side.”
His rival, Democratic Party candidate Chong Won-o, conceded defeat.
With nearly all votes counted Thursday, the Democratic Party won 12 of 16 contests for metropolitan mayors and provincial governors. Those included the governorship of Gyeonggi Province — the populous area surrounding Seoul — and the mayor’s office in Busan, South Korea’s second-largest city and traditionally a conservative stronghold. The People Power Party won the remaining four contests, including the mayorship of Daegu and two provincial governorships in the southeastern Gyeongsang region, its longtime stronghold.
In the last local elections four years ago, the People Power Party swept a majority of races. But its standing collapsed after its then-leader, former President Yoon Suk Yeol, declared martial law in late 2024, was subsequently removed from office and was sentenced to life imprisonment on insurrection charges.
By contrast, Mr. Lee’s approval ratings have soared during his time in office, buoyed by pragmatic diplomacy and a booming domestic stock market. His party had hoped to translate that popularity into a sweeping local mandate. In South Korea, mayoral and gubernatorial races are invariably seen as referendums on the sitting president.
By Wednesday evening, things appeared to go as Mr. Lee’s party had hoped, with exit polls predicting a landslide for the Democratic Party.
Explaining how he pulled off his come-from-behind win Thursday, Mr. Oh credited first the support of “young people who, despite being frustrated by the broken ladder of social mobility, dream once again of a fair and hopeful future.”
Exit polls, as well as pre-election public opinion surveys, showed Mr. Oh drawing his strongest support not only from traditionally conservative voters aged 70 and older, but also from men in their 30s and younger — a demographic that has increasingly leaned right in recent election cycles, driven by frustration over scarce job opportunities and soaring housing prices.
The Democratic Party’s loss in Seoul and the shifting loyalties of younger voters “raise red alarms” and “presage difficulties the party could face in future elections,” said Ahn Byong-jin, a professor of political science at Kyung Hee University in Seoul.
Election Day was marred by ballot shortages at several polling stations in southern Seoul, forcing citizens to wait past closing hours to cast their votes. On Thursday, Mr. Lee ordered an investigation into the shortfall.
South Korea also held parliamentary by-elections Wednesday to fill 14 vacant National Assembly seats. The Democratic Party won nine, the People Power Party four, and the remaining seat went to Han Dong-hoon — who ran as an independent after being expelled from the People Power Party following his support for Mr. Yoon’s impeachment. Elections also filled 227 lower-level local posts, with the Democratic Party again winning a majority.
Both Mr. Oh and Mr. Han opposed Mr. Yoon’s martial law and are seen as potential presidential contenders for the conservative camp. Mr. Han’s victory gives him momentum to attempt a return to the People Power Party and challenge its leadership, which has faced accusations of sympathy toward Mr. Yoon’s declaration of martial law.
“The people punished the People Power Party for martial law by giving Democrats a landslide,” said Lee Jae-Mook, a political scientist at the Hankuk University of Foreign Studies. “But by electing Oh and Han, they also voted for checks and balances and planted seeds for conservative revival.”
