Nuclear Armament Theory

An argument for possessing one's own nuclear weapons in response to North Korea's nuclear threat, it is intertwined with the NPT regime, the ROK-US alliance, and the credibility of extended deterrence

Nuclear Armament Theory

Overview

Nuclear Armament Theory (핵무장론, 核武裝論) is a security strategy argument holding that, as North Korea's nuclear and missile threats grow more sophisticated, extended deterrence (the nuclear umbrella) alone provides insufficient deterrence, and that the Republic of Korea should develop and possess its own independent nuclear weapons, or should have US tactical nuclear weapons redeployed or shared. This debate is entangled in three axes — the Nuclear Non-Proliferation Treaty (NPT) regime, the credibility of the ROK-US alliance, and the possibility of a nuclear domino effect in East Asia — making it not a simple military matter but a political issue combining diplomacy, economics, and law.

Key Content

Concepts and Spectrum

Nuclear Armament Theory is broadly divided into three forms. The first is independent nuclear development, a plan in which South Korea secures uranium enrichment and reprocessing capabilities and builds its own nuclear weapons. The second is tactical nuclear redeployment, the argument that US tactical nuclear weapons withdrawn in 1991 should be redeployed to the Korean Peninsula. The third is nuclear sharing, a plan in which South Korean pilots operate US nuclear weapons, similar to the NATO-style sharing system. In addition, there exists a middle-ground position of securing 'nuclear latency' — not building nuclear weapons immediately, but acquiring the capability to convert to them at any time on short notice.

Historical Background

South Korea hosted US tactical nuclear weapons from the late 1950s, and by 1991 roughly 950 nuclear weapons were present on the Korean Peninsula. In the 1970s, the Park Chung-hee administration pursued the introduction of a reprocessing facility from France and attempted independent nuclear development, but halted it under US pressure, and joined the NPT in 1975. In 1991, the Roh Tae-woo administration adopted the Joint Declaration on the Denuclearization of the Korean Peninsula alongside the withdrawal of tactical nuclear weapons, and concluded an IAEA safeguards agreement in 1992, cementing the denuclearization line.

Arguments in Favor

Limits to the credibility of extended deterrence: There is a persistent 'credibility of deterrence' problem — would the United States risk an attack on its own homeland to use nuclear weapons on behalf of an ally?
Advancement of North Korea's nuclear program: North Korea has codified its nuclear possession in its nuclear weapons policy law and constitution, and has expanded operational capabilities including ICBMs, SLBMs, multiple warheads, and tactical nuclear weapons.
Securing equality within the alliance: Independent deterrence would increase South Korea's bargaining power with the United States and give it the initiative in discussions on defense cost sharing and wartime operational control.
Public support: In major surveys, support for nuclear armament has remained in the 60–70% range for several years.

Arguments Against

The cost of withdrawing from the NPT: Withdrawal would entail enormous costs, including UN Security Council sanctions, strengthened export controls (NSG, MTCR), and financial and technological sanctions.
Rift in the ROK-US alliance: The United States has sought to maximally suppress nuclear proliferation among its allies, and independent nuclear development could shake the foundations of the alliance.
Nuclear domino effect: If Japan, Taiwan, Saudi Arabia, and others pursue nuclear weapons in a chain reaction, the East Asian security order would collapse.
Technical and time constraints: Considerable time and cost are required for uranium enrichment, reprocessing, nuclear testing, weaponization, and integration with delivery systems, and securing reliability without nuclear testing is difficult.
Economic blow: The contraction of trade and investment and restricted access to international finance caused by sanctions could be fatal to South Korea's export-dependent economy.

Issues of International Law

Article 10 of the NPT provides for three months' notice of withdrawal, so withdrawal is legally possible. However, it becomes entangled in a chain of issues involving the IAEA safeguards already in place, Nuclear Suppliers Group (NSG) norms, and the revision of the ROK-US nuclear cooperation agreement. The ROK-US nuclear cooperation agreement revised in 2015 retains the United States' right of consent over enrichment and reprocessing, so securing an independent nuclear fuel cycle requires separate diplomatic negotiations.

International Cases

Israel: It has not joined the NPT and remains an undeclared nuclear-weapon state, maintaining a strategy of 'nuclear ambiguity.'
India and Pakistan: They became de facto nuclear-weapon states through nuclear tests in 1998 but remain outside the NPT regime.
North Korea: It withdrew from the NPT in 2003 and has conducted six nuclear tests since 2006.
Ukraine: After giving up its nuclear weapons under the 1994 Budapest Memorandum, it suffered a Russian invasion, sparking debate over 'the price of giving up nuclear weapons.'

South Korea's Debate Landscape

The debate gained full momentum starting with remarks on nuclear armament by ruling party figures in 2013 and 2016, and President Yoon Suk Yeol's mention in 2023 of the possibility of tactical nuclear redeployment and nuclear sharing caused international repercussions. Since then, the government has officially maintained the NPT regime and a line of strengthening ROK-US extended deterrence, while adopting a dual strategy of supplementing practical deterrence through the Nuclear Consultative Group (NCG). A spectrum has formed in which the progressive camp emphasizes dialogue, denuclearization negotiations, and ROK-US cooperation, while within the conservative camp, strengthening extended deterrence and securing independent nuclear latency are emphasized.

Latest Trends

In 2024–2025, the axis of the debate shifted significantly. First, with the launch of the second Trump administration, pressure over defense cost sharing and discussions of readjusting the US military's role were reignited, bringing concerns about the 'credibility of extended deterrence' back to the fore. Second, South Korea and the United States are continuing work to concretize extended deterrence, such as through the Nuclear Consultative Group (NCG) and the joint establishment of ROK-US nuclear operations guidelines, adopting a strategy of partially absorbing the independent nuclear armament argument. Third, North Korea is strengthening its alignment with Russia, including through a Comprehensive Strategic Partnership Treaty, and seeking to make its nuclear-weapon-state status a fait accompli, shaking the very goal of denuclearizing the Korean Peninsula. Fourth, internationally, the protracted war in Ukraine and the Middle East crisis have spread discourse about 'the vulnerability of states that gave up nuclear weapons,' and discussions on expanding nuclear sharing have emerged even in NATO countries such as Poland and Germany. Fifth, public opinion in South Korea continues to favor nuclear armament, but there is a growing tendency to prefer phased alternatives such as 'securing nuclear latency' or 'tactical nuclear redeployment' over an actual policy shift. The key variables are the United States' willingness to implement extended deterrence, the responses of North Korea, China, and Russia, and South Korea's nuclear negotiating leverage.