Introduction
The notion of South Korea entering the nuclear weapons club is not merely a thought experiment but a prospect loaded with seismic consequences for global security. The ramifications are manifold, from exacerbating regional tensions in East Asia to undermining decades of painstaking nonproliferation efforts. Before welcoming Seoul into the ranks of nuclear-armed nations, one must confront a litany of serious, often overlooked questions.
Toby Dalton, a senior fellow at the Carnegie Endowment for International Peace, and George Perkovich, a leading voice in nuclear policy, have underscored the grave implications of South Korea’s nuclear ambitions. These concerns are not hypothetical musings but rooted in the realpolitik of a region teetering on the brink of militarized chaos. The recent assertion by South Korean Defense Minister Kim Yong-hyun that acquiring nuclear weapons is “among all possible options” reveals a dangerous normalization of nuclear ambitions under the guise of countering North Korea’s unrelenting threat.
South Korean politicians have flirted with the rhetoric of nuclearization for years, leveraging it to score domestic political points or intimidate Pyongyang. But this is no longer mere posturing. The specter of a nuclear-armed South Korea now looms large, fueled in part by prominent American figures like former Secretary of State Mike Pompeo, who nonchalantly suggested there’s “no reason” to object to Seoul’s nuclearization. Yet, this cavalier approach to proliferation belies the enormous risks and complexities that such a move would entail.
Why Should South Korea Go Nuclear?
The rationale for South Korea to develop its own nuclear arsenal is understandable, even compelling to some. The country faces twin nightmares: an increasingly belligerent North Korea and the prospect of abandonment by the United States, particularly under unpredictable U.S. leadership like that of former President Donald Trump.
In Washington, voices advocating for South Korea’s nuclearization argue that a nuclear-armed ally could relieve the U.S. of the burden of North Korea and free up resources to counter China. Meanwhile, within South Korea, public opinion has long tilted toward the pro-nuclear camp. Polls over the past decade consistently show majority support for acquiring nuclear weapons. Yet these polls often fail to delve into the steep costs—military, political, economic, and moral—that such a decision would entail.
But here lies the danger: what seems a logical response to North Korean aggression could become the very catalyst for an arms race in Northeast Asia, pulling the region into a vortex of instability and escalating the likelihood of war.
Achieving a Survivable Nuclear Arsenal
If South Korea were to pursue nuclear weapons, it would need a credible and survivable arsenal capable of deterring not only North Korea but also the specter of Chinese and Russian intervention. This is no small feat. North Korea already boasts an estimated 50 nuclear warheads, with enough fissile material to build at least 20 more in the near term. Matching this capacity is not a simple numbers game; South Korea would need an arsenal capable of surviving a first strike and delivering a retaliatory blow.
Given South Korea’s geography—small, densely populated, and easily targeted—its best bet would be to develop submarine-launched nuclear missiles (SLBMs). However, building such capabilities is an enormously expensive and time-intensive endeavor. It would likely take Seoul a decade or more to field a credible arsenal, requiring advanced technology, extensive testing, and sufficient fissile material.
During this precarious period of transition, South Korea would be vulnerable to sabotage by adversaries like North Korea or China. Covert operations, cyberattacks, or even preemptive strikes could derail the nuclearization process, leaving South Korea exposed and destabilized.
The Role of the United States
The U.S. would find itself caught in a quagmire during this transition. South Korea would undoubtedly expect Washington to uphold its extended deterrence commitments, essentially demanding that the U.S. shield Seoul from any fallout—literal or figurative—during its nuclearization process.
This creates an untenable paradox for Washington. How can the U.S. risk American lives to protect a nuclearizing South Korea when the very rationale for extended deterrence—to prevent nuclear proliferation—is being upended? This dilemma risks eroding not just the U.S.-South Korea alliance but the credibility of American security commitments worldwide.
If South Korea does go nuclear, the calls for the withdrawal of U.S. troops—stationed there for over 70 years—will grow louder. Already, isolationist sentiments in Congress and among the American public suggest that a nuclear South Korea could be left to fend for itself. As Senator Lindsey Graham once infamously remarked, “If thousands die, they’re going to die over there. They’re not going to die here.”
The Specter of an Arms Race
The historical record is unequivocal: the early years of nuclear proliferation are the most dangerous. From the U.S.-Soviet crises over Berlin and Cuba to the Kargil conflict between India and Pakistan, newly nuclearized states are prone to brinkmanship and miscalculation.
A nuclear South Korea would not deter North Korea or China; it would provoke them. Pyongyang might accelerate its weapons programs or adopt even more reckless postures, confident that its nuclear arsenal provides a shield against retaliation. China, in turn, could respond by further militarizing the region, deploying more advanced weaponry, and potentially pressuring its allies, including Russia, to ramp up their own activities in Northeast Asia.
Meanwhile, a nuclear-armed South Korea might feel emboldened to act more aggressively, triggering crises that could spiral out of control. The likelihood of miscalculation would skyrocket, dragging the U.S. into conflicts it might otherwise avoid.
Economic Repercussions and Sanctions
South Korea’s nuclear ambitions would come at a steep economic price. Under U.S. law, the Glenn Amendment mandates automatic sanctions against any nation conducting a nuclear test. These sanctions would not be symbolic. They would cut off foreign aid, halt defense sales, and block vital technology exports.
But the U.S. wouldn’t be the only source of economic pain. China, South Korea’s largest trading partner, has already demonstrated its willingness to use economic coercion. When Seoul deployed U.S. missile defenses in 2016, Beijing’s retaliation cost the South Korean economy an estimated $8 billion. A nuclear program could provoke even harsher penalties, crippling industries and eroding public support for nuclearization.
The Global Fallout: A Deathblow to Nonproliferation?
Perhaps the greatest danger of South Korea’s nuclearization lies in its potential to undermine the global nonproliferation regime. For decades, the world has largely adhered to the principle that fewer nuclear-armed states make for a safer planet. Only nine countries possess nuclear weapons today, thanks in no small part to U.S. and Soviet efforts during the Cold War.
If Washington condones South Korea’s nuclear ambitions, it will shred this principle. Other U.S. allies—Japan, Taiwan, Saudi Arabia—may feel emboldened to follow suit. Meanwhile, adversaries like Iran, emboldened by perceived hypocrisy, could accelerate their own programs.
The ripple effects would be catastrophic. China and Russia, no longer restrained by norms, could assist U.S. adversaries in acquiring nuclear arms. The resulting proliferation would push the world closer to the brink of nuclear chaos, with no credible mechanisms for de-escalation.
Conclusion
While South Korea’s fears of North Korean aggression are justified, the pursuit of nuclear weapons is a cure worse than the disease. It would destabilize Northeast Asia, strain alliances, trigger economic ruin, and shatter global nonproliferation norms.
The proponents of nuclearization, both in Seoul and Washington, must face these realities head-on. A nuclear South Korea may seem like a bold solution, but without a comprehensive strategy to address the cascading risks, it is nothing short of reckless. The world deserves better than to sleepwalk into a future of unchecked proliferation and unthinkable catastrophe.
