The recent debate surrounding the transfer of wartime operational control (OPCON) has unfolded in a manner somewhat different from the past. Both South Korea and the United States agree in principle that South Korea should assume a greater role and responsibility in the defense of the Korean Peninsula, and it is difficult to find any official position that outright denies the transfer of OPCON itself. The South Korean government regards a defense structure led by the South Korean military as an essential process of alliance modernization and self-reliant defense, while the United States has become increasingly explicit in raising the strategic demand that allies expand their primary responsibility for their own defense. On the surface, then, the political environment for pursuing OPCON transfer appears more favorable than at any point in the past.

However, agreement on the goal does not necessarily translate into agreement on the path to reach it. The current difference between Seoul and Washington lies not in whether OPCON should be transferred, but in what must first be prepared and what must be demonstrated before the transfer can take place. The South Korean government asks whether the South Korean military can lead, whereas the United States asks whether the South Korean and U.S. forces can continue to fight as a single force once South Korea assumes the lead. The former emphasizes responsibility, will, and the institutional normalization of the alliance. The latter places weight on the effectiveness of warfighting, the survivability of U.S. service members, and the operation and protection of the core capabilities that the United States provides. These two questions are not in conflict with one another. Rather, they represent a single set of issues that must be answered together for OPCON transfer to succeed.

Nonetheless, the domestic debate has tended to revert to the outdated framework of "early transfer" versus "indefinite postponement." Neither approach offers an adequate solution: emphasizing OPCON transfer as a matter of restoring sovereignty while treating military conditions as a secondary concern, nor citing military uncertainty as grounds for postponing the transfer indefinitely in practice. Just as political will cannot substitute for military readiness, an assessment of whether conditions have been met should not, by itself, be used to justify the permanent deferral of transfer.

Against this backdrop, this paper first examines why South Korea and the United States, despite sharing agreement on the goal of OPCON transfer, differ in their approach and priorities regarding the path to it. It then reviews, in turn, the approach that reduces OPCON transfer to a matter of sovereignty, the practice of assessing readiness through numerical completion rates, the tendency to view command structure and military capability as separate matters, and the implications of the modernization of U.S. Forces Korea for the continued need for combined command. On this basis, the paper proposes an "integrated transition" as the direction for implementing OPCON transfer, one that combines the expansion of the South Korean military's wartime leadership with combined command relationships, joint operational plans, and core U.S. support capabilities into a single coherent system.

The central issue in OPCON transfer should not be the speed of the process, but rather what kind of alliance and combined defense structure remains once the transfer is complete. If a transition expands the South Korean military's leadership while pushing U.S. strategic and military capabilities to the margins of combined operations, South Korea could end up assuming greater responsibility while its access to the means needed to fulfill that responsibility is actually weakened. Under the banner of South Korean-led command, responsibility and capability would in effect be separated. It is precisely this kind of "fragmented transition" against which this paper cautions. An integrated transition, by contrast, means more than simply replacing a U.S. commander with a South Korean commander; it means that as South Korea assumes greater responsibility, the combined capabilities and U.S. support commitments necessary to carry out that responsibility are institutionalized all the more firmly.

| How South Korea and the United States View OPCON Transfer Differently

The divergence between Seoul and Washington over OPCON transfer has recently become apparent in the statements of key figures on both sides. At the Shangri-La Dialogue in May 2026, U.S. Secretary of Defense Pete Hegseth described South Korea's more active push for OPCON transfer as a "breath of fresh air," stating that the United States should encourage allies' willingness to take on greater responsibility for their own defense. At the same time, however, he emphasized the need to find a "balance" in the transition process that would ensure the existing Operational Plan (OPLAN) and the responsibilities that U.S. service members have carried for decades would continue to be "honored." This suggests that the United States does not oppose an expanded South Korean role per se, but holds the view that it must be pursued in a way that does not undermine the existing operational plan or weaken U.S. responsibilities and force employment.

General Xavier Brunson, Commander of the ROK-U.S. Combined Forces Command and United States Forces Korea, has expressed this American concern even more directly. Testifying before the U.S. Congress in April 2026, he stated that OPCON transfer must proceed on a conditions-based approach and emphasized that "political convenience must not outpace conditions." He further noted that a focus on conditions would make both the United States and South Korea safer. Brunson's remarks encapsulate the view held by U.S. military authorities: that rather than political agreement on timing, what should first be verified are the South Korean military's command capability, the continuity of existing operational plans, and the protection and support procedures for U.S. forces.

The South Korean government, by contrast, emphasizes that the political will to pursue OPCON transfer and the overall capabilities of the South Korean military have already reached a considerable level. At the first meeting of the Future Defense Strategy Committee in May 2026, Minister of National Defense Ahn Gyu-back reported that "even if wartime operational control were returned tomorrow, we would have little difficulty defending ourselves." President Lee Jae Myung corrected him at the time, saying it would be more accurate to say "not little difficulty, but no difficulty at all," to which Minister Ahn responded, "no difficulty at all." At the same meeting, President Lee also noted that a dependent mindset still lingers in the defense field, stressing that a nation's ability to defend itself by its own strength is fundamental to statehood.

Minister Ahn reiterated this confidence in a June 2026 appearance on KBS's Sunday Diagnosis, stating that "there would be no problem for our security even if wartime operational control were returned immediately," and assessing that the ROK-U.S. combined defense posture is uniquely tight and strong by global standards and that South Korea's conventional military capabilities are sufficient. He warned that continuing to add new conditions on the grounds of a changed battlefield environment could turn the transfer into an endless deferral, adding that "although the battlefield paradigm has changed considerably, our capabilities are sufficient." In the same program, however, Minister Ahn also offered a somewhat more qualified account. He clarified in greater detail that his statement that transfer "could happen even tomorrow" did not mean that all of the South Korean military's tangible capabilities were fully in place. Noting that national defense capacity consists of both tangible elements, such as weapons systems and equipment, and intangible elements, such as morale, will, and psychological readiness, he explained that his remark was meant to emphasize the latter, namely, that South Korean service members, "from privates to generals," possess the mental readiness and will to lead under a transferred OPCON. Taken together, these remarks show that the South Korean government views the transfer not merely as the end result of military preparation, but as a task that should no longer be delayed through political decision-making.

It is at this point that the emphases of the two sides come into sharper contrast. Whereas South Korea presents the South Korean military's psychological readiness, political will, and institutional responsibility as the starting point for transfer, the United States is asking whether the military conditions, namely, the actual capability to carry out combined operations, have been met.

| The First Misconception about OPCON Transfer: A Matter of Command, Not Sovereignty

Before turning to the specific direction for implementation, it is necessary to first examine several premises that have clouded the debate over OPCON transfer. Four misconceptions recur throughout the current discussion. The first and most fundamental of these begins by equating OPCON with national sovereignty or the authority of command itself. This view holds that once OPCON is transferred, South Korea will finally be able to decide for itself whether to go to war and how to conduct military operations, and that as long as it remains untransferred, the United States controls the South Korean military. In reality, however, regardless of whether OPCON has been transferred, decisions such as the initiation and termination of war and major escalation are political matters that the two governments deliberate and determine in accordance with their respective constitutional authorities. OPCON, by contrast, is an operational authority concerning who commands the forces designated by the two countries, and under what command relationship, once such political decisions have already been made.

In other words, it is not accurate to describe OPCON transfer simply as a process of "retrieving" an authority held by the United States and returning it to South Korea. The United States does not possess South Korea's sovereignty or its authority over military command, nor does the Commander of the ROK-U.S. Combined Forces Command unilaterally command the entirety of the South Korean military. Rather, operational control over specific forces has been delegated to the Combined Forces commander in order to carry out missions jointly determined by South Korea and the United States. The essence of the transfer, then, lies not in recovering lost sovereignty, but in how the two countries' forces, decision-making, and support systems will be reconnected under a future combined defense structure led by a South Korean four-star general.

| What the "94% Met" Figure Does Not Tell Us

The recent OPCON transfer debate has drawn renewed attention, prompted by Minister Ahn Gyu-back's remarks, to the claim that South Korea and the United States assessed roughly 94 percent of the transfer conditions as having been met as of 2020. This figure carries some significance in that it demonstrates the substantial preparation and institutional progress achieved by the South Korean military and the ROK-U.S. alliance over the past several years. However, it is risky to use the 94 percent figure alone either to characterize the current state of readiness for transfer or to determine the timing of transfer. Without knowing what exactly was assessed, what weight was applied to each condition, and what the remaining 6 percent actually consists of, a completion rate may serve a political argument but offers insufficient grounds for a military judgment.

Military readiness is not an arithmetic average. Even if dozens of administrative and procedural criteria have been satisfied, an operation as a whole can still fail if a small number of decisive capabilities remain inadequate. In particular, the ability to detect and track North Korea's mobile nuclear and missile targets, secure communications and combined C4I sustained through wartime, missile detection, warning, and interception systems, joint targeting, cyber and space support, air operations and long-range precision strike, and the procedures linking conventional operations to U.S. extended deterrence are not simply one condition among many. If even one decisive gap exists among these, a high completion rate on the remaining conditions cannot compensate for it. What must be verified as the military conditions for OPCON transfer is not a completion rate, but whether the combined forces can sustain operations under the most difficult circumstances.

Changes in the security environment must also be taken into account. The current conditions-based transfer framework rests on the three comprehensive conditions agreed at the 2014 Security Consultative Meeting and the Conditions-based OPCON Transition Plan (COTP) approved in 2015. Compared with that period, however, North Korea's nuclear and missile capabilities have entered an entirely different stage, both quantitatively and qualitatively. North Korea has been developing ballistic and cruise missiles of varying ranges and launch modes, tactical nuclear weapons, unmanned aerial vehicles, and cyber and electronic warfare capabilities, and the likelihood that it could combine conventional attacks with nuclear threats has also grown. Military cooperation between North Korea and Russia is providing North Korea not only with resources and technology, but also with real-world combat experience and lessons from modern warfare.

The military conditions have long served as a kind of thorn that has delayed OPCON transfer, but given how much more severe the security reality has become, one cannot help but ask whether the conditions established in the past still hold today, and whether South Korea and the United States are, in effect, preparing for the "next war" using the standards of a previous one.

| Command Structure Is Not a Vessel for Capability, but Capability Itself

In the OPCON transfer debate, securing the South Korean military's weapons systems and operational capabilities has been treated as an important condition, yet the future command structure has tended, by contrast, to be regarded as a comparatively lesser matter of organizational design and posts. For instance, the current command structure envisioned for the Future Combined Forces Command follows the 2018 agreement between South Korea and the United States, under which an integrated command structure is assumed in which a South Korean four-star general serves as commander and a U.S. four-star general as deputy commander.

What must be guarded against at present, however, is a situation in which the political timeline for transfer moves ahead of the process, the authority of the Future Combined Forces Command and the U.S. support system fail to be sufficiently established, and the two countries' command structures end up, in effect, separated. The possibility cannot be ruled out that a de facto parallel structure could emerge on an interim basis, in which the South Korean command commands South Korean forces while the U.S. command separately controls U.S. forces and core support assets. Such an outcome could give rise to duplication and fragmentation of operational plans, delays in decision-making, divergent operational pictures, uncertainty over the request and approval of U.S. support, and conflict over the level of escalation and war objectives.

In a situation involving a nuclear-armed North Korea, these are not merely problems of inefficiency. North Korea's strategy is aimed at widening the gap between South Korea and the United States in threat perception and response levels, compressing decision-making time through nuclear threats, and driving a wedge between U.S. commitment and South Korean resolve. The more fragmented the ROK-U.S. command structure becomes, the greater the room North Korea gains to exploit fissures within the alliance.

Furthermore, there remains a considerable body of opinion holding that, because early discussions on OPCON transfer between South Korea and the United States began with a parallel command structure as their starting point, this structure should be regarded as the ultimate goal of transfer. In the security environment of today, however, one that requires confronting a nuclear-armed North Korea, this approach is no longer sufficiently persuasive. The greatest problem with a parallel transition is that while it assigns South Korea a greater share of defense responsibility, it leaves the core capabilities needed to fulfill that responsibility outside the combined command structure. In particular, under the Trump administration's transactional approach to alliance management, if the South Korean military is placed at the forefront of warfighting while U.S. intelligence assets, air power, missile defense, and strategic support remain contingent on separate consultation and approval, then rather than expanding South Korea's autonomy, the result could well be even greater uncertainty in the very manner of its dependence on the United States.

| The Modernization of U.S. Forces Korea Does Not Reduce the Need for Combined Command

Changes in the role and force structure of United States Forces Korea (USFK) are also an important factor shaping the direction of OPCON transfer. Some hold the view that as USFK shifts away from its past emphasis on large-scale ground forces toward a more mobile, technology-intensive force, the need for integrated ROK-U.S. command will correspondingly diminish. According to this logic, South Korea would take the lead in the ground defense of the Korean Peninsula while the United States provides support from outside the theater as needed, and this kind of parallel division of roles is sometimes presented as a way to secure both U.S. strategic flexibility and South Korean autonomy at the same time.

In reality, however, the modernization of USFK does not reduce the need for integrated command: if anything, it heightens it. The United States is shifting its posture away from a large, permanently stationed ground force and toward high-value support capabilities such as intelligence, surveillance, and reconnaissance, missile defense, space and cyber operations, air operations, long-range precision strike, and strategic lift and reinforcement. As South Korea takes on greater responsibility for conventional ground defense, the United States is likely to continue playing a role precisely in those domains, sensors, networks, precision strike, and escalation management, that South Korea cannot readily replace in the short term.

This does not mean that the relationship of dependence between South Korea and the United States is weakening; rather, its character is changing. In the past, the physical integration of U.S. ground units deployed alongside South Korean forces on the front line was the core of alliance cohesion. In the future, functional integration, connecting U.S. intelligence, space, air, and missile defense capabilities to South Korean operations in real time, will become the more critical element. As the physical footprint of U.S. forces grows lighter, South Korea's military may in fact come to rely even more heavily on the United States' advanced support capabilities. And because such capabilities often require separate national command channels and approval procedures, the risk grows that they will not be delivered at the moment they are needed if an integrated operational plan and command relationship are not in place.

In particular, as the role of USFK evolves to account simultaneously for the defense of the Korean Peninsula and missions across the broader Indo-Pacific region, South Korea needs to secure U.S. support not through political declarations, but through concrete operational procedures. Should crises arise simultaneously on the Korean Peninsula, in the Taiwan Strait, in the South China Sea, or elsewhere, where U.S. intelligence assets, air power, missile defense, and strategic lift capabilities are prioritized is not something that is automatically determined. If it remains unclear how such assets would be provided to the Future Combined Forces Command after OPCON transfer, South Korea's military could end up shouldering greater defense responsibility while being pushed further down the list of priorities for access to core support capabilities.

South Korea should also remain wary of the possibility that the United States favors a parallel command structure. While this could be interpreted as a choice to grant the South Korean military a greater role and more autonomy, it could equally reflect a U.S. move to preserve freedom of action over its own forces and to separate U.S. service members and strategic assets from a command structure led by South Korea. It could, moreover, signal that the United States is lowering its expectations and commitments regarding future combined ROK-U.S. operations and preparing for a gradual disengagement. Ultimately, the modernization of USFK and the expansion of U.S. strategic flexibility are not grounds for rushing OPCON transfer; rather, they are reasons why the integration that follows the transfer must be designed with far greater precision and care.

| Conclusion: Four Directions for Implementing an "Integrated Transition"

OPCON transfer should be a process of moving beyond the past pattern in which the United States has done what South Korea itself should have done. It should not, however, come to mean a shift toward a relationship in which South Korea handles everything on its own while the United States provides support from outside only when needed. In an environment marked by a nuclear-armed North Korea, DPRK-Russia military cooperation, the recalibration of U.S. Indo-Pacific posture, and a growing likelihood of simultaneous regional crises, what South Korea needs is not formal independence, but a combined defense posture that actually functions.

That South Korean military leadership must be expanded is clear. At the same time, that leadership must be paired with stable access to core U.S. military capabilities, an integrated operational plan, and unity of command. Absent this, South Korea could face the worst possible outcome: shouldering a greater share of the responsibility for warfighting while its guarantees of the capability and support needed to fulfill that responsibility grow weaker. Weakening the alliance's integration in the name of self-reliant defense would not be self-reliance at all, but strategic isolation.

The real choice regarding OPCON transfer is not between sovereignty and deterrence. Nor is it between early transfer and indefinite postponement. It is a choice between an "integrated transition," which links South Korea's greater responsibility to combined capability and to sustained U.S. commitment, and a "fragmented transition," which separates South Korea's responsibility from U.S. capability.

What this paper means by an "integrated transition" is a transition in which a South Korean four-star general leads the operational command of the Future Combined Forces Command while, first, a single combined operational plan is maintained; second, pre-agreed procedures for requesting, approving, and providing core U.S. support capabilities are put in place; third, the command relationships among the Future Combined Forces Command, United States Forces Korea, the United Nations Command, and U.S. Indo-Pacific Command are clearly defined; and fourth, a continuous joint verification system is institutionalized both before and after the transition. This is not an abstract proposal disconnected from the current combined defense system. The Future Combined Forces Command concept agreed between South Korea and the United States in 2018 was itself an institutional choice intended to combine South Korean command leadership with the continuity of combined command. Likewise, the conditions-based OPCON transition plan and combined verification are not procedures meant merely to assess the capability of individual South Korean commanders; they are processes meant to confirm whether the formulation of operational plans, command and control, information sharing, and the integration of U.S. support capabilities actually function as intended. The core of an integrated transition lies in substantively implementing and filling in the already-agreed framework of the Future Combined Forces Command.

Four directions for implementation should be considered in pursuing an integrated transition.

First, the conditions for transfer must be recalibrated not as a simple completion rate, but from the standpoint of deterrence against North Korea and the actual conduct of warfighting. Separate from the detailed assessment data that must necessarily remain classified, South Korea and the United States need to explain which core categories of capability have been verified and what decisive gaps remain.

Second, the South Korean-led Future Combined Forces Command must be able to integrate core U.S. capabilities swiftly and reliably. It is necessary to specifically verify the command relationships and procedures through which intelligence, surveillance, and reconnaissance; military satellites; combined C4I; missile detection, warning, and defense; air operations; joint targeting; cyber and space support; logistics and reinforcement; and long-range precision strike and extended deterrence capabilities are integrated into the operations of the Future Combined Forces Command. Combined exercises should be used to verify how swiftly and reliably U.S. national assets and forces from outside the theater can be connected to South Korean-led operational plans in an actual crisis or wartime situation, and any gaps identified in the process should be jointly addressed by South Korea and the United States.

Third, the transition must not be designed with the Future Combined Forces Command considered in isolation. The relationships among the Future Combined Forces Command, United States Forces Korea, the United Nations Command, U.S. Indo-Pacific Command, the UNC rear bases in Japan, the two countries' Joint Chiefs of Staff and national military command authorities, and multinational reinforcement systems must be clarified before the transition takes place. If it remains unclear through what command relationships U.S. reinforcement forces would deploy to the Korean Peninsula once war has broken out, where the authorities of the UNC and the Combined Forces Command are delineated, and how the allocation of U.S. forces would be coordinated in the event of simultaneous crises in the region, the command structure could become more complicated after the transition rather than less.

Fourth, the transition should be designed not as a one-time event but as an ongoing process of verification and refinement. OPCON transfer is not a single event completed on a fixed date, but a continuous process of verification and improvement. A joint assessment system is needed that repeatedly verifies the combined operational plan, command relationships, and U.S. support procedures both before and after the transition, and that regularly addresses the gaps identified through combined exercises.

These four directions, or standards, are not new obstacles meant to delay OPCON transfer. On the contrary, they are the standards required to bring the transfer to genuine completion. Neither pursuing an immediate transfer on the strength of political will alone, nor postponing it indefinitely on the grounds of military uncertainty, serves South Korea's interests. What is needed is to bind the expansion of South Korean military responsibility and leadership together with actual capability, operational procedures, and sustained U.S. support into a single, coherent structure.

※ The opinions expressed in 'Sejong Focus' are those of the author and do not represent the official views of Sejong Institute.