When the United States withdrew its nuclear forces from the Korean Peninsula in 1991, it could not have known how the strategic environment would change over the next three decades. Today, alternative strategies to current nuclear weapons policy are needed. Understanding the fluid nature of the nuclear threat to South Korea from the north and China is an important first step.
The Democratic People’s Republic of North Korea (DPRK) tested its first nuclear device on October 9, 2006. This action exacerbated an already significant threat perception by the Republic of Korea (ROK) and Japan. Because of the United States’ treaty agreement concerning the defense of South Korea and Japan, both nations, while uneasy, were confident in American security guarantees. In the subsequent two decades, the North Korean threat has grown considerably as has the China threat.
On December 18, 2023, the Associated Press reported that “North Korea on Monday conducted its first intercontinental ballistic missile test in five months, likely launching a developmental, more agile weapon, as it vows strong responses against US and South Korean moves to boost their nuclear deterrence plans.” The DPRK tested the Hwasong-18 ICBM. Theodore Postol argues that the Hwasong-18 is “identical” to the Russian Topol-M (SS-27 Mod 2). Jacob Gleason describes the Topol-M as having a range of 10,500–12,000 kilometers. The ranges of the Topol-M and DPRK’s Hwasong-18 are similar. According to Ridzwan Rahmat, the “Hwasong-18 is deployed onboard a nine-axled transporter-erector-launcher (TEL).”
Rahmat suggests that the Hwasong-18 is possibly equipped with multiple independently targetable re-entry vehicles (MIRV), which enhances its strategic military posture by enabling a singular missile launch to engage multiple targets concurrently. Drawing on the framework posited by Postol, which draws a parallel between the SS-27 and the Hwasong-18, it is plausible, to infer that the Hwasong-18 missile may have the capacity to carry up to four nuclear warheads.
In the context of North Korea’s growing missile capabilities, it is imperative to formulate a strategic response that effectively deters Kim Jong Un from engaging in provocations that might threaten the United States, South Korea, or Japan. Within this intricate security landscape, the United States is responsible for reinforcing and validating the trust of regional allies, specifically the ROK and Japan.
Regarding the American commitment to South Korea, the Department of Defense provides insights that emphasize the necessity of a robust and unwavering alliance framework to ensure regional stability and counter the threats posed by the DPRK’s military advancements. This necessitates a nuanced approach that balances deterrence with diplomatic engagement, thereby maintaining regional peace and security while upholding the integrity of international alliances.
As the Department of Defense recently reminded Americans, “In 1953 the United States and Republic of Korea (ROK) signed the Mutual Defense Treaty pledging to promote peace, defend against external threats, and strengthen collective defense in the Pacific region. Seventy years later, the U.S.-ROK Alliance now stands as one of the world’s premier alliances.” This is a clear statement of commitment to the alliance with South Korea. To comply with the “defend against external threats” directive, the United States needs to change its nuclear policy toward North Korea.
The Treaty of Mutual Cooperation and Security Between Japan and the United States, Article III states, “The Parties, individually and in cooperation with each other, by means of continuous and effective self-help and mutual aid will maintain and develop, subject to their constitutional provisions, their capacities to resist armed attack.” These agreements codify an American commitment to the ROK and Japan.
If either South Korea or Japan lost faith in American commitment to their security, both countries have the technical capacity to pursue their own nuclear arsenals to deter the DPRK. To prevent such an eventuality, the United States, under the auspices of the Washington Declaration, is actively expanding its assurance efforts. The success of American efforts is evinced in the South Korea announcement: “The United States and South Korea plan to draw up joint guidelines on nuclear defense strategy by the middle of next year and establish an integrated system to deter North Korea’s nuclear weapons, Yonhap news agency said on Saturday.”
For American assurance efforts to work long term, the United States must explore multiple options to mitigate the potential security threats posed by North Korea. First, the US must continue support for joint exercises, like Ulchi Freedom Shield, but also consider including greater employment of nuclear weapons. The message conveyed through exercises is simple—the US and ROK alliance is prepared, through practice, for conflict.
Second, the United States should rotationally deploy nuclear weapons on the Korean Peninsula. This will signal North Korea that the United States is deeply committed to South Korean security. However, this strategy requires cautious execution to avoid provoking China, which could lead to unintended consequences.
Third, the United States could also undertake a continuous deployment of nuclear weapons on the Korean Peninsula. They were in South Korea for decades and widely accepted by South Koreans. Nuclear weapons would be more welcome today given North Korean nuclear pursuits.
China is certain to respond negatively to any of these options, as would North Korea. However, the consequence of doing nothing may produce a situation that allows the DPRK to push the escalation rhetoric and provocations to the point of conflict.
North Korea’s growing nuclear arsenal and China’s nuclear breakout are increasingly concerning for South Korea and Japan as both nations see these efforts as a clear threat to their own security. American commitment to the ROK and Japan remains on shaky ground, despite the positive steps taken since the Washington Declaration. Countering those threats with a very clear commitment of American nuclear weapons may prove just the right demonstration of commitment to friend and foe alike.
James M. Ragland is a Fellow at the National Institute for Deterrence Studies. The views expressed in this article are the author’s own.
