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South Koreans wonder: Will the U.S. still protect us from North Korea?

U.S. Defense Secretary Lloyd Austin, left, shakes hands with South Korean Defense Minister Lee Jong-sup after a news conference following their meeting in Seoul on Jan. 31. (Jeon Heon-kyun/Pool/AP)
7 min

TOKYO — The mood around Unification Village, just south of the inter-Korean border, has grown tense the past two years as North Korea ramps up its ballistic missile tests. Most recently, North Korean drones even infiltrated the border.

“It is time we went nuclear,” said Lee Wan-bae, who has lived for 50 years in the village, just three miles south of the Military Demarcation Line that marks the official border between the two Koreas.

For decades, Lee has had a front-row view of the fluctuating border tensions amid failed efforts to disarm North Korea. “It increasingly looks like matching the nuclear threat from North Korea is the solution that will bring long-desired stability to our village life,” Lee said.

With North Korea threatening to strike the South with nuclear weapons and no sign of a return to denuclearization talks, South Koreans are increasingly debating whether they can still trust the United States to protect them in case of war on the peninsula.

The shifting geopolitical landscape around South Korea in the past year — an unprecedented number of missile launches from North Korea, Russia’s nuclear saber-rattling and growing fears that China will invade Taiwan — has prompted South Koreans to take a sober look at their security dependence on the United States.

At the same time, the South Korean public has become ever more supportive of having their own nuclear weapons, a sentiment that was once considered fringe but is now mainstream.

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As a signatory to the international Non-Proliferation Treaty (NPT), South Korea is banned from developing or acquiring nuclear weapons. South Korea remains under the protection of the U.S. nuclear umbrella, which guarantees that the United States would use its nuclear weapons to protect South Korea if needed. This U.S. commitment to protect allies is also referred to as “extended deterrence.”

There is now urgency to reexamine the credibility of the arrangement. Some South Korean analysts wonder: Would the United States really deploy its nuclear arsenal to protect South Korea? And would it do so even during the Russian invasion of Ukraine or a Chinese invasion of Taiwan?

“While South Korea may have, in the past, similarly sought assurance from the United States … current discussions are different because of the drastic changes in the threat environment” and the circumstances surrounding South Korea, said S. Paul Choi, principal at the Seoul-based consultancy StratWays Group and a former South Korean military officer.

Risks of conflict breaking out in multiple places at once, such as in Europe and in East Asia, or in multiple places within the East Asia region, “further raise concerns about U.S. capacity to deliver on its commitment,” Choi said.

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South Korean leaders are grappling with this public discourse, which has intensified in the past month after South Korean President Yoon Suk Yeol mentioned offhand the possibility of going nuclear as a policy option, though he suggested it was an unrealistic one. He later walked back the comment, saying he was “fully confident about the U.S.’s extended deterrence.”

Several South Korean officials reaffirmed the country’s trust in the alliance and commitment to the NPT. But they acknowledged the need to strengthen the allies’ response to North Korea and said their discussions with the United States are focused on how to set and meet those goals.

South Korean officials also view their trilateral efforts with the United States and Japan to respond to the North’s threat, such as drills and increased communication, as another way to overcome the credibility gap.

“Having our own nuclear weapons is not a realistic option. But the fact that the public wants it is a reflection of their security concerns,” said a senior South Korean official, speaking on the condition of anonymity to discuss sensitive matters. “What the public feels is important. We need to discuss between South Korea and the United States to increase their trust and make them feel like extended deterrence is not just declarative.”

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North Korea is barreling forward on its five-year nuclear development plan, with leader Kim Jong Un vowing an “exponential increase” in its arsenal this year. In September, North Korea adopted a more aggressive law stating it could use nuclear weapons “if any forces try to violate the fundamental interests of our state.” The North is also advancing tactical nuclear weapons, which have a lower explosive yield and fly shorter ranges — and are directed at the South.

“Security concerns deepened among the South Korean public over the North’s recent push for short-range missiles and tactical nuclear capacity, which are seen as immediate threats,” said Jina Kim, a security expert at Hankuk University of Foreign Studies in Seoul. As North Korea evolves in its nuclear ambitions, the allies should also adjust their efforts to deter Pyongyang by preparing for specific scenarios of nuclear attacks, she said.

U.S. Defense Secretary Lloyd Austin and his South Korean counterpart, Lee Jong-sup, last week met in Seoul to discuss how to reaffirm the U.S. commitment to South Korea. They announced new measures, including holding a nuclear tabletop exercise this month and expanding the “level and scale” of their combined exercises, according to a joint statement.

Choi said South Korea seeks a greater role and involvement in the alliance’s deterrence efforts, not just by consulting on policies, but also by having a hand in how those policies are put into place and how joint military operations are designed and carried out.

South Korean policymakers are most worried about the leaders of North Korea and China no longer believing that U.S. pledges on extended deterrence are credible, he said. That is particularly the case when it comes to whether the United States would use its nuclear weapons to defend South Korea.

Throughout much of the Cold War, the United States stationed nuclear-armed weapons in South Korea. Then, in 1991, President George H.W. Bush initiated the withdrawal of all tactical nuclear weapons deployed abroad. In 2016, then-South Korean President Park Geun-hye reportedly asked the United States to redeploy the tactical weapons but was denied.

Public polls over the past decade have shown a steady rise in support for South Korea going nuclear, ranging from 60 to more than 70 percent of the population. A new poll released last week by the Seoul-based Chey Institute for Advanced Studies found that an overwhelming 76.6 percent of 1,000 respondents support domestic nuclear weapons capability.

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A Biden administration official, speaking on the condition of anonymity to discuss sensitive matters, said that the United States has been clear that there would be “overwhelming response” in the case of a nuclear attack, and that U.S. policymakers believe South Koreans understand the “costs and benefits and tremendous risks” of having their own nuclear weapons.

Kim, from Hankuk University, added that although there is popular support, there has not been enough debate on the potential downsides of going nuclear. The South Korean military’s nuclear pursuit in violation of the NPT would also deal a blow to the country’s civilian nuclear industry, she said.

Still, analysts agree that the two countries need to do more.

“Assurance is less about whether the adversary is deterred but more about making US allies feel protected,” wrote Go Myong-hyun, research fellow at the Asan Institute for Policy Studies in Seoul. “While there is little the alliance can do militarily to prevent North Korea from carrying out missile launches and nuclear tests, it can and should do more to strengthen assurance.”

Kim reported from Seoul.