SEOUL, South Korea — Just how split is South Korea, a nation squeezed for centuries between Northeast Asia’s big powers, on how to deal with its neighbors?

One clue could be seen at a recent debate ahead of the March 9 vote to determine South Korea’s next leader. The conservative candidate said he’ll meet U.S. President Joe Biden first if elected. The liberal hopeful, who is neck-and-neck in polls with the conservative, wouldn’t give a firm answer. A minor contender said she would welcome North Korean leader Kim Jong Un before anyone else. And no one mentioned making Chinese President Xi Jinping a priority.

The answers reveal serious division as Seoul looks to navigate a complex geopolitical reality. Just what path South Korea takes matters because the nation is playing an increasingly important role in a region that the United States, China and Europe consider crucial.

Among Seoul’s foreign policy challenges are an intensifying rivalry between its top ally, Washington, and its top trading partner, China; a fast-advancing North Korean nuclear program; and badly strained ties with Japan, the world’s third largest economy.

As pressure on Seoul builds, some observers worry the candidates vying for the presidency lack a clear, long-term vision for how to move forward.

“Whoever becomes president, they’ll face an extremely difficult foreign policy and security situation,” said Kim Heung-kyu, director of the U.S.-China Policy Institute at Ajou University in South Korea. “We’re now seeing a fight for hegemony in the region again.

“If we underestimate or take lightly this situation, I’d say we’ve failed to learn the lessons of history.”

Geographically sandwiched among big powers, the Korean Peninsula has long been vulnerable to foreign invasions and influences.

In the late 19th and early 20th centuries, when Japan took on China and then Russia for regional supremacy, the peninsula was often a battleground. Japan then imposed a 35-year colonization, which still plays a part in South Korean political discourse. At the end of World War II, the peninsula was divided into a U.S-backed, capitalist South and a Soviet-supported, socialist North. The Koreas then fought a devastating 1950-1953 war that drew in American and Chinese troops.

South Korea has since grown into one of Asia’s richest democracies and a global cultural powerhouse. The present U.S.-China tensions, however, pose a strategic security dilemma, with South Korea’s outgoing liberal President Moon Jae-in struggling to strike a balance between Washington and Beijing.

Both nations have pressured Seoul to take their side. In 2017, for instance, China retaliated economically against South Korea over its decision to allow the United States to install a missile defense system in the country that Beijing says can spy on its territory.

Another perpetual problem for Seoul is rival Pyongyang.

As U.S.-China frictions emerge, North Korea will likely be a less urgent policy priority in both Washington and Beijing. That could help the North retain its weapons of mass destruction, including recently tested sophisticated nuclear-capable missiles that can defeat South Korean defense systems, some analysts say.

There are also worries about a quest to strengthen a security partnership among three strong democracies — the United States, South Korea and Japan — amid renewed historical disputes between Seoul and Tokyo, whose relationship is now at a low point since their normalization of diplomatic ties in 1965.

South Korea often finds it “difficult to determine how to act in relation to the United States and China,” said Kim Taewoo, a former head of the state-funded Korean Institute for National Unification in Seoul. “North Korea’s nuclear advancement has also crossed a redline. The weapons that it has recently displayed are game-changers.”

The leading South Korean presidential candidates have fiercely debated how to address these problems.

Yoon Suk Yeol, the conservative contender, vows to make a stronger U.S. alliance the heart of his foreign policy. He wants to strengthen trilateral military cooperation with Washington and Tokyo, launch preemptive strikes on North Korea if it shows signs of attack, and take a more assertive stance on China.

His main rival, liberal Lee Jae-myung, favors pragmatic diplomacy between Washington and Beijing, saying picking a side would be “the most dangerous idea.” He said his North Korea policy would be similar to Moon’s appeasement approach, saying he would push for exemptions from U.N. sanctions to restart dormant inter-Korean economic projects. He takes a tougher stance on Japan than Yoon.

During their first TV debate last month, Yoon said he would meet Biden first, then Japanese Prime Minister Fumio Kishida, then China’s Xi and then North Korea’s Kim.

Lee said he would analyze the situation before making such a decision. Sim Sangjung, a liberal candidate who placed distant fourth in recent surveys, said she would seek a summit with Kim first.

Lee and Yoon clashed over the Russian invasion of Ukraine as well.

During another televised debate Feb. 25, Lee condemned Russia but also called Ukrainian President Volodymyr Zelenskyy a political novice whose push for a NATO membership provoked Moscow and triggered the conflict. Yoon slammed Lee, saying the Ukraine war proved why a country needs a strong defense capability and a powerful ally in the face of external threats.

Lee later said his comments were taken out of context, saying he aimed to point out Yoon’s “dangerous views on foreign policy and security,” not to criticize Ukraine’s president.

Yoon and Lee’s policies appear to be a repeat of past policies, and both have failed to explain how exactly they would address the security challenges and what immediate action they would take, said Du Hyeogn Cha, an analyst at Seoul’s Asan Institute for Policy Studies.

Both Lee and Yoon lack experience in foreign affairs. Lee is a former provincial governor and city mayor; Yoon is a former prosecutor general who entered party politics only last year. They accuse each other of making sensational, populist campaign promises.

If Yoon becomes president, some analysts worry he may be unable to avoid friction with Beijing and Pyongyang, though he may boost ties with Washington and repair frayed ties with Tokyo. A Lee government would likely be criticized for tilting toward Beijing and away from Washington, and for sympathizing with Pyongyang too much — the same criticism leveled at Moon’s government.

“They need to talk about a grand strategy,” Park Won Gon, a professor at Seoul’s Ewha Womans University, said of the rivals. “Lee’s camp is talking about pragmatism and Yoon’s camp speaks of national interests, but they are both very vague concepts.”

South Korea faces the difficult tightrope walk of solidifying its alliance with the United States while avoiding any moves that can antagonize China. It will also likely need stronger ties with Japan and other nations that share worries about China’s rise.

Kim Heung-kyu, the institute director, said South Korea doesn’t need to be passive as Washington and Beijing compete. He said South Korea’s advanced semiconductor industry and other capacities make it an attractive partner for both countries.

“South Korea is now a linchpin to both the United States and China,” he said. “If we fail to make use of what we have, that would be very painful, incompetent and irresponsible.”

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