Korea must help reinforce nuclear umbrella

Chun In-bum

A recent Foreign Affairs article by Jennifer Lind and Daryl G. Press, "The Broken Nuclear Umbrella," has reignited a debate on a decision South Korea can no longer afford to postpone. Their central argument is unsettling but difficult to dismiss: As adversaries acquire the ability to strike the American homeland, the credibility of U.S. extended nuclear deterrence inevitably comes under greater strain. The uncomfortable question they pose is one that alliance planners have quietly wrestled with for years: Would any American president willingly risk Los Angeles to save Seoul?

Whether one agrees with their conclusion or not, the diagnosis deserves serious attention.

At nearly the same time, another development underscored the rapidly changing strategic environment in Northeast Asia. A succession of high-level diplomatic exchanges among North Korea, China and Russia — including Chinese Politburo Standing Committee member Wang Huning's visit to North Korea and continued engagement between Beijing and Pyongyang leaders following North Korean Foreign Minister Choe Son-hui's earlier consultations — illustrates that the three authoritarian powers are strengthening political and strategic coordination. While this emerging relationship is not a formal military alliance, it reflects an increasingly aligned strategic outlook among states that challenge the existing regional order.

South Korea should recognize what this means.

The strategic environment on the Korean Peninsula is no longer defined solely by North Korea's nuclear weapons. It is increasingly shaped by a broader network of revisionist powers whose military, diplomatic, technological and economic cooperation complicates deterrence.

If authoritarian states are strengthening their strategic integration, democracies must do the same.

Some interpret this reality as an argument for South Korea to pursue an entirely independent nuclear arsenal. Others argue that Seoul should simply continue relying on the existing U.S. nuclear umbrella. Both approaches are incomplete. An independent nuclear force would risk weakening alliance cohesion, complicating intelligence sharing and creating uncertainty during crises. At the same time, expecting the United States to solely shoulder all nuclear responsibilities indefinitely ignores the changing balance of strategic risk. There is a better alternative.

South Korea should develop a sovereign nuclear deterrent, not as an independent national project, but as an integral component of an allied deterrence network led by the United States and supported by other democratic partners. Ownership and integration are not the same thing.

South Korea may own the capability, but deterrence should remain firmly embedded within the alliance.

The United States possesses decades of experience in nuclear command and control, personnel reliability, weapons security, intelligence fusion and crisis management. Rather than distancing itself from a nuclear-capable South Korea, Washington should help ensure that any future deterrent meets the highest standards of safety, transparency and operational discipline. Koreans should view American assistance not as diminishing South Korean sovereignty but an enhancing of alliance credibility. Such cooperation could include integrated early warning, shared intelligence, nuclear consultation, common safety standards, crisis communications and agreed decision-making procedures. The objective should be to maximize deterrence while minimizing the risks of miscalculation or unauthorized use. This differs fundamentally from uncontrolled nuclear proliferation. Instead, it represents an evolution of allied deterrence for a more dangerous century.

Critics often assume that a nuclear South Korea would inevitably lead to the withdrawal of U.S. Forces Korea (USFK). I believe precisely the opposite. If South Korea were to possess a nuclear deterrent, the presence of USFK would become even more important. USFK is far more than a conventional combat force. It serves as the visible manifestation of America's commitment, provides unmatched intelligence and surveillance capabilities, integrates missile defense, ensures combined operational planning and offers a critical mechanism for escalation management during crises. Nuclear weapons alone do not prevent war. Credible alliances do. USFK would remain the indispensable bridge connecting South Korea's national deterrent with the broader military and political power of the United States. Another benefit is often overlooked.

For decades, diplomacy with North Korea has revolved around the increasingly unrealistic objective of complete, unilateral denuclearization. That objective has not produced results. A stable deterrence relationship would not guarantee successful negotiations, but it could eventually shift diplomacy toward more practical objectives: strategic stability, crisis communication, transparency measures, risk reduction and, if political conditions evolve, meaningful arms control.

History suggests that durable arms control agreements emerge not when one side enjoys overwhelming advantage, but when all parties recognize that coercion has become prohibitively costly. Deterrence and diplomacy are not opposing concepts. Credible deterrence often creates the conditions under which diplomacy becomes possible. None of this would be easy. It would require difficult legal, political and alliance questions to be addressed. Decision-making authority, alliance consultation, verification mechanisms and compatibility with international nonproliferation objectives would require careful design.

Yet these are challenges of implementation, not reasons to avoid the discussion altogether.

The real danger lies in assuming that the strategic environment of 1995 still exists in 2026. The alliance between South Korea and the United States has always evolved to meet new realities. From conventional deterrence during the Cold War to combined operational planning after democratization,today's expanded nuclear consultation, the alliance has repeatedly adapted without abandoning its fundamental principles.

The question is no longer whether the nuclear umbrella is under pressure. The question is whether the democratic allies that have preserved peace in Northeast Asia possess the vision to reinforce it before it tears.

Retired Lt. Gen. Chun In-bum is the former commander of the Republic of Korea Army Special Warfare Command.