SEOUL – Few nations look as vulnerable to nuclear strikes as South Korea.
The country lies directly south of fierce rival North Korea, which has been nuclear-capable since 2006. Since 2021, Pyongyang has been expanding its existing long-range strategic deterrent – which most believe is aimed at the US – by developing shorter-range tactical capabilities.
Off-peninsula developments are equally sobering. Russia has successfully ring-fenced its February invasion of Ukraine by threatening nuclear use against any nation that dares to cross its red lines. As a result, while Kiev receives moral, financial and arms support from Western partners, it stands alone on the battlefield.
South Korea, unlike Ukraine, has a national insurance policy: The US is treaty-bound to defend it. However, there is the question of US resolution; the credibility of that insurance is untested in the face of real-world nuclear aggression.
Some fret that – if push came to shove – Washington would be unwilling to risk losing one or more of its cities to a North Korean reprisal, leaving South Korea exposed to potential perdition. Against this fraught backdrop, a simmering issue is now heating up again: The possibility of South Korea joining the nuclear club by developing a home-grown deterrent.
One of the highest-profile proponents of that possibility put a stark question to Asia Times on the sidelines of a recent conference. “How can we sleep at night?” asked political heavyweight and Hyundai Heavy chairman Chung Mong-joon.
Currently, institutes are churning out research showing that the public overwhelmingly supports the national acquisition of nuclear arms. It is increasingly a hot topic at conferences and in media.
But with the Yoon Suk-yeol administration cleaving tightly to a US that is still strongly attached to nuclear non-proliferation, there is no tangible momentum. And any South Korean leader who decided to go critical would need to first answer the multiple questions that hang over the issue.
Politically: What sanctions might South Korea face and how would the development affect Seoul’s security relationship with its key ally the US? Moreover, how might China and Japan react?
Technically: Is South Korea capable of creating both nuclear arms and their delivery systems? And if it built a nuclear weapon, where would it test it?
The case for going nuclear
That the Korean public is in favor of a domestic nuclear deterrent is clear.
A Chicago Council on Foreign Relations poll in February found that 71% of Koreans favored developing a domestic nuclear deterrent. A May poll conducted by the Asan Institute for Policy Studies found that 70.2% were in favor – with 63.6% favoring an independent nuclear deterrent even if led to sanctions.
The matter was in the open at this month’s Asian Leadership Conference 2022 in Seoul, with a dedicated discussion panel.
“People are talking about this now,” said panelist Robert Kelly, an American professor of political science at Pusan National University. “It is more blunt and open than ever before.”
A key reason to proceed would be to directly deter North Korea, which has defied all efforts by all parties to halt its nuclear arms programs.
“Despite decades of efforts to denuclearize North Korea, we are faced with what looks like an imminent seventh nuclear test…and that may not be the end of it,” said Lee Jung-hoon, a professor of international relations at Seoul’s Yonsei University who moderated the ALC discussion.
“So that begs the question: ‘If North Korea does go ahead, what are we to do? More condemnation, more UNSC resolutions, more sanctions?” Lee continued. “That has not worked for two decades.”
America is strongly attached to the Nuclear Non-proliferation Treaty, or NPT, raising worries that Washington would crack down if Seoul decided to go nuclear. But other power players would not be likely to sanction Seoul beyond lip service.
“I see no appetite in the EU to sanction South Korea for going nuclear, and the same with Japan and Taiwan,” Ramon Pacheo Pardo, a professor of international relations at Kings College London told Asia Times. “I don’t see the EU doing anything other than official condemnation.”
Moreover, Article 10 of the treaty would allow South Korea to exit the NPT in good faith.
“Acquiring nuclear weapons is not a violation of international law – only for those countries who are members of the NPT,” said Daryl Press, an associate professor at Dartmouth College. “South Korea could do it in a legal fashion by exercising its Article 10 legal rights to withdraw…there is no need to be a pariah.”
For a South Korean diplomat, explaining the necessity of the step would be “an easy day on the job,” Press suggested.
In fact, signaling an NPT withdrawal could be a legitimate step on Seoul’s response ladder, Lee proposed. “If [North Korea] conducts a seventh nuclear test, the least we can do is withdraw from the NPT,” he said. “That would put a lot of pressure on the international community to do more.”
Experts are divided regarding how much or little pressure Beijing has exerted over the years on Pyongyang to denuclearize and how much leverage it realistically possesses. But any proposed Seoul withdrawal from the NPT – and the additional possibility that Tokyo would follow that lead and tip over the nuclear threshold – would certainly trigger alarm bells in Beijing.
“China will strongly oppose this step,” Press said. “But the South Korean position is eminently reasonable: South Korea should hold open other options and say, ‘If there is some way the international community, perhaps led by China, to get North Korea to denuclearize, we would happily rejoin the NPT.’”
He added, “I would not phrase this as a threat to the Chinese, but a reach out of the hand.”
Others say that not even Beijing – a key source of fuel, food and medicine for North Korea – can reign in Pyongyang.
“North Korea has already demonstrated that they don’t give a damn about the US, the UN and China,” Chun In-bum, a retired South Korean general told Asia Times. “The North Koreans will eat each other before they give up nuclear weapons.”
A key argument for Seoul’s nuking up is the possibility of the US backing down if faced with a truly locked-and-loaded North Korea.
“The core issue is that North can strike US with an ICBM and in doing so you introduce the classic dilemma: [French President Charles] De Gaulle asked [US President John] Kennedy if he would exchange New York for Paris,” Kelly said of the 1961 discussion between the two leaders. “Kennedy waffled. I think the answer is probably ‘no.’” I don’t believe the US would fight a nuke war solely for non-Americans.”
In this sense, South Korean nuclearization would not just aim a close-to-home deterrent at North Korea but could also lower risks for the US. And the nuclearization of US allies France and UK during the Cold War provides a European benchmark that could be applied to Asian allies South Korea and Japan, Kelly said – warning the US not to act in “hegemonic” fashion.
America’s public, he guessed, would be supportive. “My sense is that the issue of North Korea is so obvious it will move US public opinion, and the US foreign policy community will come around,” he said.
Policy cleavages between Seoul and Washington provide another rationale for independent nukes, Press said. The rise of China and the “wedge” being driven “between South Korean and US priorities” is not yet “catastrophic” but is a “growing strain,” the American scholar said.
Rising fears are also hovering over not American strengths but rather its weaknesses.
In war, Washington is acutely casualty-sensitive and in recent conflicts has arguably lacked the political will to win. Moreover, US society and politics are deeply – some say dangerously – polarized. These chinks in America’s armor may be leveraged by a wily foe.
“Korea needs a very stable US, but right now the US is trying to find itself or to be reborn,” Chun said. “As they do this, enemies will see an opportunity.”
Cheong Seong-chang, who directs the Center for North Korean Studies at the Sejong Institute think tank, argued that the nuclearization of South Korea and/or Japan would rebalance Northeast Asia’s tilted strategic geography.
“There is tilted ground that will be more and more tilted…Russia, China and North Korea all have nuclear weapons,” he told the ALC. Conversely, among Japan, South Korea and the US, only the latter possesses a nuclear deterrent.
Chun agreed. “The US faces such a variety of challenges now,” he said. “It is only natural that Korea should have the ability to help the US in whatever situation.”
So could South Korea pull it off?
Nuclear feasibility
There is no question about the “what” of the issue. South Korea, a highly-educated G10 economy that is home to a competitive nuclear power sector that exports reactors, could independently create atomic arms.
One method of producing the core of a nuclear weapon is by reprocessing plutonium fuel rods. Using spent fuel from the Wolseong nuclear plant, “We can create 4,000 nuclear weapon units,” Cheong said.
While Cheong did not specify kilotonnage, that would be a massive armory: World leader Russia is believed to field fewer than 6,000 nuclear warheads. The six-reactor Wolseong, in the country’s southeast, started operations in 1983.
It is not just plutonium South Korea could leverage. “Korea also has uranium enrichment technologies held by only a handful of countries in the world,” Cheong said.
In 2000, the Korea Atomic Energy Research Institute tested laser enrichment technology, according to a 2016 article in the Chosun Ilbo, that was reproduced by the Non-Proliferation Policy Education Center. Using that, 1 kilogram of highly enriched U-235 could be produced in around four hours. The article also reported that the country already produces the kind of industrial alloys needed to encase fissile materials.
The question then is “when” – how long would the process take if the political will was mustered? Experts differ on the question.
The 2016 article estimated it would take six months to produce fissile materials and six-nine months to develop a detonation device – an overall timeline of approximately 18 months.
Others believe it could be done more quickly. In a widely quoted comment, Suh Kune-yull, a professor of nuclear engineering at the elite Seoul National University told the New York Times in 2017, “If we decide to stand on our own feet and put our resources together, we can build nuclear weapons in six months…the question is whether the president has the political will.”
A more recent June 2022 commentary in the military website War on the Rocks by Lami Kim, who directs the Asian Studies Program at the US Army War College, found, “Although South Korea has advanced nuclear technologies…Seoul would still need three to five years to acquire a workable nuclear arsenal.”
It was unclear if Kim was discussing device production or a full nose-to-tail system. The latter would include the development of nuclear doctrine and leadership protocols; the creation of a dedicated command-and-control net; and the marriage of the device with delivery systems.
Addressing a full program scenario, Cheong was more optimistic. “If we pursued it at very high speed, we could have fully usable and deployable weapons within two years,” he said. “At slow speed, three years would be enough.”
In terms of delivery systems, South Korea looks to be good to go. Given that North Korea borders the country, tactical nuclear devices could be fired via tube or rocket artillery. But Seoul has ex-peninsular reach, too.
The country has successfully tested submarine-launched ballistic missiles. More recently, the successful June launch of the Nuri space rocket proved that the country is de facto intermediate-range ballistic missile-capable, given the dual use of booster technologies.
There is one hole in this otherwise impressive armory of capabilities. To be a credible deterrent, any nuclear device must be physically tested. So where could South Korea potentially conduct one?
North Korea has tested devices in underground tunnels in a remote, mountainous area. That is near-impossible for South Korea for reasons of population densities and politics.
The South has nearly double the population of its northern rival – 52 million versus the North’s 26 million – all compressed into a smaller land area – 100,210 square kilometers versus the North’s 120,540 square kilometers.
And authoritarian Pyongyang does not have to consider popular push back against its policies, while democratic Seoul must contend with street politics and NIMBYism related to defense, energy and other issues.
In recent years, there have been high-profile protests against a naval base on Jeju Island, nuclear reactors and the placement of a US anti-missile battery.
Still, Cheong hinted – tantalizingly – that the issue has been discussed.
“Where a nuclear test would be done is a very sensitive question – there are few candidate [locations] where tests are possible,” he said. “If this was tabled, the residents would protest, so I cannot disclose.”
One possibility could be a Bikini Atoll-style seafloor test off of one of the uninhabited islands that ring South Korea’s coast.
It has long been rumored – but never proven – that Imperial Japan test-detonated a nuclear device on an island off the coast of northeastern Korea in the waning days of World War II.
The case against
Despite energetic discussion in specialist circles, the acquisition of a nuclear deterrent is currently not on the national political agenda.
One reason – counter-intuitively – is that it has customarily been liberal Seoul governments that have pursued independent defense capabilities.
The process of moving wartime operational control (“OPCON Transfer”) of the South Korean military from Washington’s grip to Seoul’s was initiated by the leftist Roh Moo-hyun government that was in office from 2003-2008.
Subsequently, the Moon Jae-in administration (2017-2022) oversaw the lifting of US-set range caps on South Korean missiles and tested submarine-launched ballistic missiles. It also tabled the acquisition of an aircraft carrier, while pressing ahead with (still incomplete) OPCON transfer.
The latter program is costing the Korean taxpayer billions – and adding a nuclear capability would add to the burden.
“An indigenous nuclear program would consume and divert enormous funding from South Korea’s defense budget,” Bruce Klinger, senior fellow for Northeast Asia at US think tank The Heritage Foundation told Asia Times. “South Korea’s defense funding would be better spent augmenting conventional force requirements as stipulated in South Korea’s Defense Reform Plan 2.0 and the bilateral plan” for OPCON transfer.
Conservative administrations, such as Yoon’s, have historically been unadventurous on defense, preferring to place maximum trust in the US. Hence, Seoul is not courting Washington’s displeasure by initiating a nuclear deterrent.
“The Yoon administration, like its predecessors, has declared it will not pursue an indigenous nuclear weapons program,” Klinger said.
This ambiance is reflected in the caution some feel. “We would lose more than we gain,” a person familiar with the topic told Asia Times.
It is sensitive: The moderator of the ALC discussion, Lee, noted that the topic was “…politically controversial and, perhaps, not politically correct.”
Doubly so given that movement on the issue could so alarm Washington that it could spark the risk that has stalked South Korean politics since the Donald Trump administration: A withdrawal of US troops.
“An attempt by Seoul to keep a major military capability separate from the combined and integrated command structure would be antithetical to the foundation of the bilateral alliance as well as long-standing US counter-proliferation policy,” Klinger warned.
“Such a step could lead to calls for reduction or withdrawal of US forces either due to concerns of possible independent South Korean actions or isolationist perceptions that Seoul could now go it alone.”
Kim wrote for War on the Rocks that if an irked US withdrew support, South Korea would be acutely vulnerable during the time it took to craft its deterrent.
A further risk is likely sanctions damage – such as the heavy hit Korea Inc suffered from Chinese retaliation after Seoul established a US THAAD anti-missile system on South Korean soil in 2017.
And there is another issue – one that lurks deep below the surface.
“Advocacy for developing an indigenous South Korean nuclear capability seems grounded more on national prestige rather than strategic considerations,” Klinger said.
Pollsters admit it. “Public attitudes on nuclear weapons do not strongly align with rationales for armament offered by some South Korean politicians and analysts,” the Chicago Council conceded.
The council found that acquisition of home-grown nuclear muscle in the Korean public mind is not aimed exclusively at North Korea.
“Threats other than North Korea” are a “main driver of support” the Chicago Council found – with 55% of respondents saying China will be the biggest threat to South Korea in ten years.
Meanwhile, 26% of South Koreans considered national prestige as the key reason for their support for nuclear arms, higher than those who see the aim being to counter North Korea, who came in at just 23%.
These findings may reflect deep-seated public emotion.
A 1993 South Korean novel, “The Rose of Sharon is Blooming Again” – the reference is to the national flower – became a best-seller and was turned into a movie in 1995. It depicts North and South Korea joint-developing nuclear arms to take on national bete noire, Japan.
Be that as it may, Chun puts forward a final rationale for going nuclear.
“It’s a volatile world with multiple challenges and we need multiple capabilities and flexibilities,” he said. “There is so much we can prepare for.”
Follow this writer on Twitter @ASalmonSeoul
