Nuclearization has long been a taboo inside the South Korean government. When analyzing arguments against South Korea’s development of independent nuclear weapons, it becomes clear that they have overlooked or intentionally ignored the security benefits that South Korea would acquire through nuclear arms while exaggerating the risks of intangible losses. It is now questionable whether South Korea should still be shy to raise its voice about nuclear weapons, given the military rise of the People’s Republic of China (PRC) and North Korea’s development of advanced weapons of mass destruction, which the United States and the West couldn’t stop. All major arguments against South Korean nuclearization lose their persuasiveness when considering that South Korea could initiate its own nuclear program under the frames of “controlled proliferation” and “conditional nuclearization.”

The NPT and Nuclear Domino Theory

The most common concern about nuclearization is that South Korea’s withdrawal from the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) would bring severe economic sanctions from the UN Security Council. North Korea withdrew from the treaty, but it wasn’t the actual reason why the UN sanctioned Pyongyang. Also, the NPT guarantees signatories the right to exit when their supreme interests are threatened. Thus, the South Korean government can leave the treaty based on the justification that the increase of nuclear threats from North Korea undermines Seoul’s supreme security interests. South Korea can even avoid sanctions, as Seoul would not need public nuclear tests because it already has more developed nuclear technology than North Korea. More importantly, if South Korea suggests it will exit from the treaty, it can send a clear message to the PRC and the North that Seoul is open to all available options, increasing South Korea-U.S. influence over Kim Jong-un’s nuclear arsenal.

It is possible that Washington might oppose South Korean nuclearization at first, but it is likely to accept it to deter both Pyongyang and Beijing. If sanctions are ever imposed on South Korea, a global economic power, for developing its nuclear weapons, they wouldn’t last long if Seoul’s nuclear weapons supported the United States’ efforts to deter the PRC. When India conducted its fifth nuclear test in 1998, U.S.-led sanctions only lasted for three years. Then, when President George Bush visited India in 2005, both states signed a nuclear pact in order to check the PRC. As was the case with India, a democratic state that accepts International Atomic Energy Agency (IAEA) safeguards and non-proliferation obligations as a nuclear-armed power can be an exception from the NPT and Washington’s nuclear policy. Democratic South Korea passes this test, and its nuclear armament would eventually serve U.S. interests.

Despite widespread concern, the NPT won’t collapse if South Korea develops nuclear weapons, and an additional “nuclear domino” effect would not occur, as the treaty is in effect despite controversies about AUKUS and an NPT regime that tolerates de facto nuclear-armed states. There has always been concern about proliferation and instability whenever a new nuclear state appears, but proliferation has not surged, and the international order has not collapsed. It is a luxury for non-nuclear South Korea to care about the vested interests of nuclear-armed states when Seoul is still incapable of taking proportional countermeasures against Kim Jong-un’s nuclear threats.

Strictly speaking, the nuclear domino effect has already come to Asia’s Eastern bloc. The two driving factors for this phenomenon are North Korean nuclear weapons—developed with the connivance of the PRC and Russia—and the nuclear imbalance that comes from the lack of equivalent strategic weapons among U.S. allies in East Asia. Countries like South Korea and Japan that need to protect themselves in such an uneven playground should not be held accountable for a nuclear arms race.

Fears that other countries would proliferate if South Korea nuclearized are exaggerated. Most countries do not meet the conditions necessary for nuclear armament because they lack economic power, developed nuclear technology, enriched uranium or plutonium, and nuclear delivery platforms. Since Southeast Asian states are also not economically stable, they are more tempted to position themselves as advanced developing countries, rather than abandoning economic development for nuclear armament. Taiwanese nuclearization is also not realistic given that Taipei faces the PRC. It would be a red line, breaking the “One China” policy and prompting Beijing to take over Taiwan.

South Korean nuclearization would not necessarily be followed by Japanese proliferation, given the very strong anti-nuclear sentiment among the Japanese public, cumulatively fostered by previous nuclear experiences. However, even before the development of North Korean nuclear weapons, Japan acquired dual-use space rockets that could be used as intercontinental ballistic missiles and ready-to-use plutonium. Therefore, Seoul’s nuclear arms would not drive changes to Japan’s national nuclear capacity, which is already complete.

There is a very slight chance that Japan could go nuclear first, but the United States and South Korea should not be wary of this. Even though the ROK-Japan relationship has been influenced by historic and nationalistic animosity, the two states share common democratic values and security interests in deterring both the PRC and North Korea, which the United States supports. If Tokyo decided to support nuclear burden-sharing in the region to impose a siege against Pyongyang and Beijing, Seoul and Washington might have to welcome Japan, or even Australia, to create a collateral security system such as an “Indo-Pacific Nuclear Alliance,” as nuclearized South Korea itself would still need to cooperate with them to confront Chinese military and economic assertiveness.

Convincing the World

Considering that Europe is so distant from Pyongyang, the European Union (EU) would not care very much about South Korean proliferation and would only express diplomatic concern. Thus, South Korea could elicit the EU’s connivance as long as the West was convinced by the justification that Seoul’s nuclearization could be an effective countermeasure to prepare for Chinese and North Korean nuclear threats. Then, this leaves only the United States as Seoul’s most important partner to persuade. Before long, North Korea’s growing nuclear forces, the PRC’s military rise and acquiescence to Kim’s illegal activities, and South Korea and Japan’s concerns would limit Washington’s options, possibly leading the White House to secretly welcome the nuclearization of its key partner. By agreeing to let the IAEA and the United States monitor Seoul’s nuclear proliferation through a third party, South Korea could still respect the non-proliferation principle and the nuclear control of the White House, addressing the concern that the ROK-U.S. alliance would be weakened in nuclear and security cooperation.

Contrary to common perceptions, eliciting the PRC’s toleration of South Korean nuclear armament is quite simple. If the PRC needs to choose between a non-nuclear South Korea that does not have any option but to accept America’s demands and a nuclear-armed South Korea that can act more flexibly with nuclear leverage, Beijing is likely to prefer the latter based on its wishful thinking that Seoul would continue hedging against the United States.

In addition, the ROK-U.S. alliance and U.S. influence in the region would not be weakened by South Korea’s development of nuclear weapons. Moreover, it wouldn’t harm the nuclear cartel enjoyed by the great powers. With nearly nine out of ten South Koreans holding a favorable view of the United States, South Korea is well aware of the importance of the ROK-U.S. alliance. Moreover, with hostile states making up more than half of East Asia, friendly relations between the United States and a nuclearized South Korea are essential, which means Washington would be able to tacitly accept Seoul’s nuclear deterrent to check anti-U.S. states in the region.

Extended Deterrence and Cost-efficiency

Some still contend that improved extended deterrence through NATO-style nuclear sharing or the redeployment of U.S. tactical nuclear weapons is a solution. However, the need for U.S. authorization for nuclear use would make such solutions symbolic and would not bring nuclear parity. Also, American nuclear weapons in the region would only provoke Beijing and Pyongyang to backlash against the consolidation of U.S. influence, and they would not see South Korea as a nuclear-armed state. It is notable that the PRC economically retaliated against South Korea for deploying the U.S. THAAD air-defense system but did not move when Seoul revealed new ballistic missiles. Thus, a nuclear umbrella is an outdated stopgap measure that was effective only when North Korea was in the early phase of its nuclear program. It provides temporary deterrence and cannot be a permanent security solution for the nuclear standoff in the Korean Peninsula.

Regrettably, the United States has publicly pledged to consider the use of nuclear weapons only in extreme circumstances to defend the vital interests of itself and its allies. But even the recent high-level deterrence dialogue failed to clarify what its declared “overwhelming and decisive” response to a nuclear strike would be. There has never been a clear or documented standard that defines when and how nuclear retaliation would be immediately executed.

In terms of budget concerns, nuclear development and maintenance costs are not astronomical. Considering the political message and deterrence provided by nuclear arms, nuclearization is a much cheaper strategic asset than conventional forces, as South Korea has already acquired the ground-based ballistic missiles, submarine-launched ballistic missiles, and fighter bombers necessary for the nuclear triad. South Korea’s well-established safety management of nuclear facilities has also provided ample technical experience. Additionally, as the purpose of South Korean nuclear development would be to deter the neighboring Eastern bloc, it would not necessitate long-range ballistic missiles or costly strategic bombers.