Millions of South Koreans are voting Tuesday for a new president in a snap election triggered by the ouster of Yoon Suk Yeol, a conservative who now faces an explosive trial on rebellion charges over his short-lived imposition of martial law in December.

Pre-election surveys suggested Yoon’s liberal archrival, Lee Jae-myung, appeared headed for an easy win, riding on deep public frustration over the conservatives in the wake of Yoon’s martial law debacle.

The main conservative candidate, Kim Moon Soo, has struggled to win over moderate, swing voters as his People Power Party remains in a quagmire of internal feuding over how to view Yoon’s actions.

This election serves as another defining moment in the country’s resilient democracy, but observers worry a domestic divide worsened after Yoon's martial law stunt is far from over and could pose a big political burden on the new president.

The past six months saw large crowds of people rallying in the streets to either denounce or support Yoon, while a leadership vacuum caused by Yoon’s impeachment and ensuing formal dismissal rattled the country’s high-level diplomatic activities and financial markets.

The winning candidate will immediately be sworn in as president Wednesday for a single, full term of five years without the typical two-month transition period. The new president will face major challenges including a slowing economy, President Donald Trump’s America-first policies and North Korea’s evolving nuclear threats.

Voting began at 6 a.m. at 14,295 polling stations nationwide that will close at 8 p.m. Observers say the winner could emerge as early as midnight.

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As of 2 p.m., more than 13 million people had cast their ballots. Combined with the 15 million who voted during last week’s two-day early voting period, voter turnout stood at 65.5%. South Korea has 44.4 million eligible voters.

Final pitches made by rival candidates

In a Facebook posting on Tuesday, Lee, whose Democratic Party led the legislative effort to oust Yoon, called for voters to “deliver a stern and resolute judgement” against the conservatives over martial law.

In one of his final campaign speeches Monday, Lee argued that a win by Kim would mean the “the return of the rebellion forces, the destruction of democracy and the deprival of people’s human rights.” He also promised to revitalize the economy, reduce inequality and ease national divisions. He urged the people to vote for him,

Kim, a former labor minister under Yoon, warned that a Lee win would allow him to wield excessive power, launch political retaliation against opponents and legislate laws to protect him from various legal troubles, as his party already controls parliament.

Lee “is now trying to seize all power in South Korea and establish a Hitler-like dictatorship,” Kim told a rally in the southeastern city of Busan.

Lee’s positions would impact nation’s direction

Lee, who served as governor of Gyeonggi province and mayor of Seongnam city, has been a highly divisive figure in South Korean politics for years.

As a former child laborer known for his inspirational rags-to-riches story, Lee came to fame through biting criticism of the country’s conservative establishment and calls to build a more assertive South Korea in foreign policy. That rhetoric has given him an image as someone who can institute sweeping reforms and fix the country’s deep-seated economic inequality and corruption.

His critics view him as a dangerous populist who relies on a political division and backpedals on promises too easily.

On foreign policy, Lee has not made any contentious remarks recently and has steadfastly vowed to pursue pragmatic diplomacy. He has called South Korea’s alliance with the U.S. the foundation of its foreign policy and promised to solidify a trilateral Seoul-Washington-Tokyo partnership, a stance that is not much different than the position held by South Korea’s conservatives.

Experts say there aren’t many diplomatic options for South Korea as it tries to address Trump’s tariff hikes and calls for South Korea to pay more for the cost of the U.S. military presence, as well as North Korea’s headlong pursuit of nuclear weapons. Experts say that has made both Lee and Kim avoid unveiling ambitious foreign policy goals.

Lee’s government still could become engaged in “a little bit of friction” with the Trump administration, while Kim’s government, which prioritize relations with Washington, will likely offer more concessions to the U.S., said Chung Jin-young, a former dean of the Graduate School of Pan-Pacific International Studies at South Korea’s Kyung Hee University.

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Chung predicted Lee won’t be able to pursue overly drastic steps on foreign policy and security, given the country’s foreign exchange and financial markets are very vulnerable to such changes.

Lee has preached patience over Trump’s tariff policy, arguing it would be a mistake to rush negotiations in pursuit of an early agreement with Washington. Kim has said he would meet Trump as soon as possible.

On Monday, South Korean trade officials held an emergency meeting to discuss a response to Trump’s announcement that the U.S. will raise tariffs on steel and aluminum products to 50% beginning June 4. South Korea’s central bank last week sharply lowered its 2025 growth outlook to 0.8%, citing the potential impact of Trump’s tariff hikes and weak domestic demand worsened by the political turmoil of past months.

Prospects for improved North Korea relations are unclear

Relations with North Korea remain badly strained since 2019, with the North focused on expanding its nuclear arsenal while refusing dialogues with South Korea and the U.S.

Since his second term began in January, Trump has repeatedly expressed his intent to resume diplomacy with North Korean leader Kim Jong Un, but Kim has so far ignored the offer while making Russia his priority in foreign policy.

Lee, who wants warmer ties with North Korea, recently acknowledged it would be “very difficult” to realize a summit with Kim Jong Un anytime soon. Lee said he would support Trump’s push to restart talks with Kim Jong Un, which he believed would eventually allow South Korea to be involved in some projects in North Korea.

Foreign policy strategists for Lee understand there isn’t much South Korea can do to bring about a denuclearization of North Korea, said Paik Wooyeal, a professor at Seoul’s Yonsei University.

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He said Lee also doesn’t share the Korean nationalistic zeal held by ex-liberal President Moon Jae-in, who met Kim Jong Un three times during his 2017-22 term.