The nuclear proliferation threat in the Korean Peninsula: Moving towards a South Korean nuclearization?

For the past two years, the tensions in the Korean Peninsula have only been growing, as well as the calls for nuclear weapons to protect themselves in South Korea against their conflictive neighbors in North Korea. However, is the menace really that urgent? Is the acquisition of nuclear weapons really feasible for South Korea, and would the United States approve of it?

The escalating missile hazard from North Korea has stirred South Korean President Yoon Suk-Yeol to indicate in January 2023 that the country may require to consider acquiring its nuclear weapons to front its fierce neighbor. The leader of South Korea’s ruling party has warned that the country may have to “seriously consider” developing its own nuclear weapons as a deterrent to its northern neighbor in the wake of Pyongyang’s latest barrage of missile tests, the last of them having taken place on March 22, 2023 into waters off the east coast of the Korean Peninsula. Even if the government officially clarified later that this is not on South Korea’s current policy nor objective’s list, some powerful voices echoed on this vision, such as Chung Jin-suk, leader of Yoon's conservative People Power Party, and Seoul's mayor Oh Se-hoon, a prospective 2027 presidential candidate. On the streets of Seoul, the public opinion is apparently favorable to developing this technology, and the growing military activity on the other side of their border is only raising even more concern on the matter.

In February, North Korea also showcased its advanced intercontinental ballistic missiles in a military parade, and only in the year 2022, North Korea launched at least 95 ballistic and other missiles, breaking its own startling record. Moreover, back in November 2022, one of the missiles landed less than 60 km away from South Korean territorial waters, south of the Northern Limit Line, the disputed maritime border between both countries. In addition to this, it is crucial to bear in mind that technically both countries are still at war, and that hostilities have only stopped due to a truce negotiated back in 1953, but still today no peace treaty has been signed and the countries remain divided, and no plausible reunification in sight in the near future.

South Korean public opinion

With all the recent events in mind, it becomes easier to comprehend the growing preoccupation of the South Koreans as well as their attempts to acquire weapons to protect themselves from North Korea, which has been recently qualified as their “enemy” for the first time in years, another last proof of the escalation of tensions between the two countries.

While South Korean public support toward nuclear weapons acquisition has been fluctuating around 50%throughout the last decade, recent public opinion polls indicate that public support for nuclear weapons has grown to 71% of its population. This growing support has been backed up by the government, which has, for the first time since 1991, started to seriously consider the possibility to become a nuclear state, due to the volatility and insecurity of the region, opening a debate that has never been so controversial.

In order to do so, one of the possible scenarios that South Korean policymakers could advocate for is a close collaboration with the US, that should be materialized through a return of US nuclear weapons. However, some of the most conservative parties in South Korea would rather opt for a national nuclear program to counteract Kim Jong-Un's menaces.

A nuclear-sharing program with the US

While the debate around developing its own nuclear arsenal is gaining repercussions and support in the public opinion mainstream, the more reasonable alternative for South Korea appears to be part of a nuclear-sharing program with its tightest ally, the United States. Both governments have been working closely on security and defense affairs since the end of the Second World War. In fact, the United States stationed tactical nuclear weapons in South Korea from the late 1950s to the end of the Cold War, but in the present day, neither the weapons nor the storage facilities are available for immediate redeployment.

Despite this, it is important to assess whether supporting South Korea’s potential nuclear program is advantageous for the United States or not, as permitting and even helping South Korea to produce nuclear weapons could set a risky precedent and uplift other countries in seek of such a powerful technology to do so. It is also crucial to bear in mind that if South Korea becomes a nuclear actor, this could also trigger more tensions in the East Asian region, something that neither China nor the US are willing to do.

Within this context, the media have shown how the US government opposes South Korea's pursuit of nuclear weapons. Nonetheless, the United States assumes the seriousness of the situation with North Korea, and to deter possible attacks or further escalation in the conflict, advocates for diplomatic and economic measures, such as even more economic sanctions on the country, in hopes that this will stop North Korea from continuing with its missile tests.

Is it really feasible for South Korea on its own?

In addition to the lack of willingness of Washington to assist South Korea in a possible nuclear program, 67% of South Koreans, when asked in a recent poll, confessed to prefer an independent capability and not so much to rely on the United States if the time comes to develop their own nukes.

In technological terms, it is important to state that South Korea has what is known as ‘nuclear latency’ meaning it has the possession of “some or all of the technologies, facilities, materials, expertise (including tacit knowledge), resources, and other capabilities needed to develop nuclear weapons”; a clear indicator of how it could develop nuclear weapons if desired, or at least, a good first step towards that objective. In fact, its own president announced that “we can have our own nuclear weapons pretty quickly, given our scientific and technological capabilities”. Moreover, the country is one of the top global producers of nuclear energy and has 25 nuclear power reactors. There are, however, some flaws in South Korea’s nuclear infrastructure, added to the fact that the country lacks uranium and some of the requiring capacities to work with it.

Another important facet to consider is that South Korea is a state party to the Nuclear Non-proliferation Treaty (1968) since 1975. Due to this fact, if the government decided to acquire nuclear weapons, the country would have to withdraw from the treaty, thus losing international prestige and reputation, since South Korea has always been a strong voice advocating for nuclear disarmament. The Nuclear Non-Proliferation Treaty bans all countries except for the five recognized nuclear weapon states from owning nuclear arms. In exchange, the countries possessing nuclear weapons have to fulfill the obligation to aid non-nuclear states, such as South Korea, in developing peaceful nuclear energy, as well as to promote global nuclear disarmament.

This treaty is refraining many other actors from becoming nuclear, being of utmost importance when it comes to trust-building between states and global security. If South Korea breaks or leaves the treaty, it may even be subject to harsh sanctions and repercussions, despite it being a right to leave (article 10) for “extraordinary events, related to the subject matter of this treaty, have jeopardized the supreme interests of its country”. A three months' notice must then be given to the UN General Assembly, for it to decide whether the claim is legitimate and in accordance with the right of withdrawal or not, and it is not very clear whether a possible South Korean nuclear acquisition could fit in. As a matter of fact, North Korea is the only country that has ever left said treaty, back in 2003.

Final thoughts and future perspectives

Seoul faces an intricate dilemma between pursuing nuclear armament for its security or upholding its nuclear leadership role in the global order. If Seoul decides to pursue nuclear capability, it will not only signify the erosion of the NPT but also cast doubts on its reliability, as well as the United States'. Additionally, it remains to be seen whether South Korea is able, technologically and materially wise, to develop such technologies on its own, since it seems hugely improbable that the United States would provide some help in this regard apart from the already existing economic and diplomatic sanctions to North Korea.

Consequently, despite the general population of South Korea (along with some politicians) being favorable to the development of their nuclear arsenal, as well as the conflict with North Korea escalating these past times, and even though the country possesses the necessary technologies to, at least, start developing them, it looks like this scenario is quite unlikely considering the international panorama nowadays. Would South Korea decide to go nuclear, the country will encounter serious opposition, as it is one of the signatories of the Non-Proliferation Treaty, and a strong advocate against nuclear weapons in the past decades. For the same reason, even its closest allies, such as the United States, are openly not favorable to this decision, as it will very likely increase the geopolitical tensions in the area. According to President Yoon’s declarations, it is very likely that South Korea will opt for strengthening its alliance with the United States, and so the nuclear bomb remains as a long-term possibility.