[인터뷰] Inside the Mind of a Veteran South Korean Diplomat
-천영우(한반도미래포럼 이사장,前 외교안보수석)
One of South Korea’s most seasoned diplomats sits down to speak candidly about the US-ROK alliance and U.S. national security strategy. Ambassador Chun Yungwoo has seen the alliance from nearly every angle — as a Six-Party Talks negotiator, as National Security Advisor to a South Korean president, and as a close observer of Washington’s strategic thinking over decades. So, when he reads through the Trump administration’s new strategy document and says his “initial reaction was one of genuine concern,” that is not a throwaway line.
In this interview, he offers his perspective about the alliance and what challenges lie ahead for South Korea. He shares his views on OPCON transfer with a perspective that cuts against the conventional wisdom in Seoul. He presents a measured but clear-eyed take on uranium enrichment and what it means for South Korea’s strategic posture.
This is a conversation about the future of one of America’s most critical alliances told by someone who helped build it.
Ambassador Chun, this morning’s roundtable was one of the most engaging and, frankly, sobering conversations I’ve been a part of in a long time. The room was filled with a palpable sense of unease about where the alliance is headed. The meeting discussion was all off-the-record, so we’ll leave it there — but it’s clear the stakes feel very real right now. This leads me to ask — late last year and earlier this year, the Trump administration released its new National Security Strategy (NSS) and National Defense Strategy (NDS). For those who were not in the room, can you share your views of these documents? In your professional opinion, what do these documents mean for the US-ROK alliance and for South Korea?
Reading through the new NSS and NDS, my initial reaction was one of genuine concern. What struck me most was what was not in these documents. There is no mention of North Korea’s denuclearization and there is no reaffirmation of the extended deterrence commitment to the Republic of Korea (ROK). I believe these are the core tenets of our alliance, and their absence in these documents was somewhat troubling to me.
There is also a passage suggesting that ROK is capable of taking primary responsibility for deterring North Korea with a more limited level of U.S. support. Now, I understand the direction this is pointing; greater burden-sharing and ROK’s self-reliance are legitimate goals. But one has to ask: Was it wise or even necessary to put that in writing in these documents? It risks sending the wrong signal to our adversary, creating misunderstanding both in Seoul and in Pyongyang, and potentially in Beijing as well.
What also concerns me is these documents’ overall strategic emphasis. It gives the impression of prioritizing the First Island Chain and the defense of Taiwan (non-treaty ally) over the defense of treaty allies like ROK and Japan. I understand why Taiwan may be important for the U.S… but the documents seem to be asking U.S. allies to build up their forces for the defense of the First Island Chain rather than for their own defense. That is a difficult ask.
On China, the strategic language has also shifted noticeably. The new documents frame the goal as achieving a “decent peace” through balance of power, deconfliction, and de-escalation. I thought this represents a retreat from the previous posture that characterized China as a strategic competitor requiring sustained competition and containment. To me, it smells of appeasement, and it suggests a willingness to concede a sphere of influence to Beijing. I think that is a significant departure.
Will this immediately upend the alliance? Perhaps not in the near term. But when ROK’s defense is no longer explicitly featured in America’s stated strategic priorities, the credibility of the extended deterrence commitment and the broader defense guarantee are inevitably called into question. That is a slow-building risk that we cannot take lightly.
What I find somewhat ironic, however, is that the administration in Seoul (which is actively pursuing strategic autonomy and an early return of wartime operational control) does not appear particularly alarmed by these shifts in American strategy. One wonders whether their comfort with greater distance from U.S. strategic commitments makes them less sensitive to these signals than they ought to be.
During the last Security Consultative Meeting (SCM) in Seoul, South Korea, and the United States announced that they will complete the second phase of OPCON transfer by the end of this year (2026). The view among many experts is that OPCON transfer will be completed before the end of President Lee’s term. What is your view on this matter? What risks should South Korea and the U.S. be aware of as they press ahead with OPCON?
Yes, President Lee Jae-myung appears intent on completing OPCON transfer before the end of his term. This will be a consequential decision, and I want to offer a perspective that may surprise some — because I support an early transfer, but for reasons quite different from those usually cited by some of my colleagues in Seoul.
Let me first be clear about what I do not believe. I do not think OPCON transfer is primarily a matter of military sovereignty or national pride. Some people in Korea tend to frame it this way, but that framing misses the point. In terms of pure operational control capability — command and control systems, ISR (intelligence, surveillance, and reconnaissance) assets, precision strike capability, strategic communications — ROK simply cannot match the United States. From a strictly military-operational standpoint, it would remain optimal for the United States to exercise wartime operational control.
So why do I support an early transfer? The reason is this: More than 70 years have passed since the Korean War ended. For over seven decades, ROK’s military has not held wartime command over its own forces in its own territory. I worry about what that prolonged dependency does to the soul and readiness of our military. If this continues indefinitely, we risk being stuck with Korean Armed Forces that lack genuine ownership of their own national defense — an institution that follows orders but does not feel the full weight of responsibility for defending its homeland. Restoring that sense of ownership and accountability matters more to me than optimizing operational efficiency.
Now, I take seriously the concern about potential gaps in deterrence through operational inefficiency during the early stage of transfer. But I believe this can be managed through thoughtful design and planning. The key is a robust consultation-and-consensus mechanism built into the command structure. When a Korean commander leads the Future Combined Forces Command, major operational decisions should require genuine deliberation with the U.S. deputy commander. Conversely, for air and maritime operations where U.S. commanders would lead, decisions should likewise require agreement with Korean deputies. If this is done properly, the actual conduct of operations need not look dramatically different from today’s arrangements — but it would address the legitimate desire of those who see this as a matter of Korean agency.
As for the concern that OPCON transfer would decouple the alliance — I think that fear is overstated. The decision to go to war or seek peace is not made by military commanders. It is made by the political leadership of both countries — the respective presidents and defense ministers. The Combined Forces Command exercises only military operational authority within the parameters set by those civilian leaders. Decoupling is a political phenomenon, not a military one, and it will not be caused or prevented by which general wears four stars in Seoul.
Let’s now turn our attention to another matter having to do with uranium enrichment and reprocessing, which has been an issue of contention between Seoul and Washington for some time. Currently, the U.S. and South Korea maintain a civil nuclear (123) agreement, which limits South Korea’s ability to enrich and reprocess spent fuel; but during the last summit, President Trump agreed to support South Korea’s pursuit of uranium enrichment and spent fuel reprocessing provided that they would be for peaceful purposes and consistent with existing laws. As I recall, you’ve worked on nuclear issues before. What do you think about this agreement?
On this agreement, I want to say first and most directly: I think it deserves credit. The agreement is a positive step, and it has been a long time coming.
Consider the basic energy security argument. ROK operates 25 nuclear power plants. We depend entirely on a small number of foreign enrichment companies for one hundred percent of our nuclear fuel supply. That is an extraordinary vulnerability for a country that is dependent on foreign sources for its energy. If those supplies are disrupted — for geopolitical, commercial, or logistical reasons — we face potential economic catastrophe. A country of our size and sophistication, with our level of dependence on nuclear energy, has a compelling case for developing its own enrichment capability. The energy security rationale alone is sufficient justification.
But there is also a security dimension that I think is underappreciated in public discussion. Even if we are talking purely about civil enrichment for peaceful purposes — and I want to be clear that is what this agreement addresses — the operation of a domestic enrichment facility does mean that ROK would have the latent technical capacity to produce weapons-grade material within a relatively short timeframe if circumstances ever demanded it. I am not suggesting we should pursue that path. But it is an objective reality that this capacity, even for civil use, reinforces deterrence and gives ROK a degree of strategic weight that complements America’s extended deterrence guarantee. That is not a trivial consideration.
On the reprocessing side — specifically pyroprocessing of spent fuel — I would counsel patience and realism. The economic and commercial viability of pyroprocessing has not yet been demonstrated at scale. We are still at the stage of needing a pilot plant, and that pilot plant’s results will have to prove the technology’s commercial case before any serious investment in full-scale reprocessing infrastructure makes sense. Beyond the technology, finding local governments in ROK willing to host reprocessing facilities — which carry real risks of radiation exposure — will itself be a lengthy political process. Reprocessing is a worthy long-term goal, but it remains a distant future prospect. We should not oversell it.
In sum, the enrichment agreement is a meaningful and welcome development. It addresses a genuine strategic and energy security need, and it reflects a maturing of the bilateral relationship on one of its most sensitive dimensions. I hope both governments will continue to advance this agenda with the care and deliberateness it deserves.
[Stimson Center, 2026-02-26]
https://www.stimson.org/2026/inside-the-mind-of-a-veteran-south-korean-diplomat/