General Brunson’s Emphasis on CJADO and the Acceleration of ROK-U.S. OPCON Transfer Talks: South Korea’s Policy Challenges

Executive Summary

The discussion on the transfer of wartime operational control (OPCON) has entered a phase where the gap between the political timeline and military-technical preparations is widening. This is driven by two parallel developments: nominee Kang's call for an early transfer and General Brunson's emphasis on implementing Combined Joint All Domain Operations (CJADO). The momentum from the U.S. side appears to stem not from consideration for South Korea, but from its own need to realign its forces, including the potential redeployment of U.S. Forces Korea (USFK). Given the pattern of repeated delays since the 2018 agreement, a dual-track response that prepares for both an early transfer and continued postponement is necessary. South Korea should focus its policy resources not on the speed of the transfer itself, but on securing a voice in the establishment of the command and control system by substantively participating in the CJADO standards design phase. Japan's experience of designing the reorganization of the U.S. Forces Japan headquarters and the integration of the JSDF's Joint Operations Command as a single track offers a key insight: the formation of the Future Combined Forces Command and discussions on the CJADO architecture should not be treated separately but handled at a single negotiating table.

I. Situational Analysis

Situational Analysis: General Brunson’s Emphasis on CJADO and the Acceleration of ROK-U.S. OPCON Transfer Talks

1. Background and Developments

The institutional framework for the OPCON transfer was established by a 2018 agreement between the ROK and U.S. governments. The core of this framework is the Future Combined Forces Command (Future CFC), which would be led by a South Korean four-star general as commander and a U.S. four-star general as deputy commander [6][9]. Since the Moon Jae-in administration, the actual implementation of this plan has been repeatedly pushed back across successive governments. This is because the principle of a "conditions-based transition" has been applied in a way that requires new verification items with each new administration.

The discussion regained momentum due to a shift in the U.S. policy line. In a potential second Trump administration, figures like Under Secretary of Defense for Policy Elbridge Colby have clearly expressed their intention to transfer OPCON to the South Korean military [6][9]. This is not a separate issue but is intertwined with a review of USFK redeployment. This is supported by the fact that the Pentagon is reportedly considering reassigning about 4,500 of the approximately 28,500 USFK personnel to other areas in the Indo-Pacific region [12]. A South Korean research institute assesses that the Trump administration's approach to alliances tends to be defined by bilateral transactions rather than reciprocal relationships, noting that "all relationships, including alliances, are defined as bilateral deals led by Trump" [12]. The pressure on NATO members to increase defense spending is being applied in a similar form to South Korea and Japan [12].

2. Current Situation

At the 2026 ROK-U.S. Combined Warfighter Forum, General Brunson, Commander of the ROK-U.S. Combined Forces Command (CFC), stressed the urgency of implementing Combined Joint All-Domain Operations (CJADO). This can be read as a call not just for a simple transfer of command authority, but for a redesign of the operational concept itself. At the same time, General Brunson made it clear that political expediency should not override military readiness [1]. This suggests a temperature difference within Washington's military command between the political rhetoric surrounding the timing of the transfer and the preparedness of working-level units.

On the South Korean side, the new defense minister nominee reaffirmed the principle of an "early transfer with no added conditions" [1]. The nominee, Kang, dismissed concerns about a perception gap between Seoul and Washington regarding the transfer timeline [1]. This statement coincides with the 2027 defense budget being set at 73.27 trillion won, an 8.2% increase from the previous year [6]. This can be interpreted as a signal that the narrative of self-reliant defense is being backed by substantial financial support. The leadership of the Democratic Party of Korea has also stated that strengthening independent defense capabilities is not contradictory to strengthening the ROK-U.S. alliance [20]. A political consensus that transcends party lines appears to be forming.

However, a domestic research institute points to the possibility that the acceleration of political rhetoric and the actual pace of the transfer may move separately, citing the pattern of repeated delays since the 2018 agreement [6]. The institute suggests that South Korea should formulate its response based on the premise of continued uncertainty rather than an imminent transfer [6].

3. Key Actors and Stances

General Brunson, Commander, ROK-U.S. Combined Forces Commandemphasizes the implementation of CJADO while remaining wary of the political timeline outpacing military readiness [1]. His remarks highlight that the OPCON transfer is not merely a change in command relationships but requires a redesign of the entire operational command and control system. Similarly, U.S. Chairman of the Joint Chiefs of Staff General Caine has warned that the proliferation of autonomous weapon systems could make unit formations themselves targets to be "hunted" on the future battlefield, stressing the need for a posture shift in the joint force [7]. This shows that the CJADO discussion is not limited to the Korean Peninsula but is linked to the operational concept transformation of the entire U.S. military.

South Korean Defense Minister Nomineehas publicly reaffirmed an early, not conditions-based, transfer, taking a stance that prioritizes political speed [1]. This, combined with the tangible measure of a defense budget increase, can be read as a strategy to lend weight to the narrative of self-reliant defense [6]. However, it remains unclear how this position will be coordinated with the actual military readiness verification process.

U.S. Department of Defense Policy Line(such as Under Secretary of Defense for Policy Colby) has expressed intent for an early transfer to the South Korean military, but this is driven less by a desire to strengthen the alliance and more by the broader framework of redeploying U.S. strategic assets and shifting burdens within the region [6][12]. There have also been instances of desynchronization, such as President Trump's personal channel ordering a reduction in military exercises without prior coordination with the Pentagon bureaucracy [16]. This indicates that even among U.S. actors, there is no complete agreement on the speed and method of the transfer.

South Korean Political Circles, including the Democratic Party of Koreahas taken the position that strengthening independent defense capabilities and strengthening the ROK-U.S. alliance can go hand in hand, creating a political current that supports the OPCON transfer [20].

4. Key Issues

The first issue is the gap between political rhetoric and military reality. General Brunson's warning shows that this gap is recognized even within Washington [1]. The key will be how the South Korean political framing of an "early transfer with no added conditions" can be reconciled with the technical and operational requirements of implementing CJADO.

The second issue is that the OPCON transfer is not a simple handover of command authority but is linked to the much larger task of integrating a multi-domain operations system. CJADO presupposes integrated command and control across not only land, sea, and air, but also the space, cyber, and electromagnetic domains [4]. This means that the pace of modernizing the South Korean military's information and command systems could become a practical constraint on the timing of the transfer.

The third issue involves the concurrent variables of the realignment of U.S. Forces Korea (USFK) and the adjustment of United Nations Command (UNC) functions. The consideration of a 4,500-strong regional force and the push to establish a UNC brigade may seem separate from the transfer of wartime operational control (OPCON), but they are in fact intertwined with the broader reorganization of the command structure on the Korean Peninsula[12][16]. If these three variables become entangled instead of being handled on separate negotiating tracks, there is a risk that the South Korean government’s negotiating leverage could be weakened[16].

II. In-Depth Analysis

In-Depth Analysis: General Brunson’s Emphasis on CJADO and the Acceleration of ROK-U.S. OPCON Transfer Talks

1. Root Cause Analysis

The fundamental reason for the repeated delays in the OPCON transfer discussion lies in the design of the 2018 agreement itself. That agreement adopted the principle of a "conditions-based transition" [6][9]. This principle created a structure that allowed for agreement on the direction of the transfer while enabling the timing to be postponed indefinitely. This means that the institutional space was left open for each new administration to add new verification items. Consequently, the transfer has repeatedly followed a pattern of being pushed to the "next stage."

This pattern began to shift not because of internal factors in South Korea, but due to changes in the U.S. policy line. The defense policy of a potential second Trump administration, led by figures like Under Secretary of Defense for Policy Colby, has clearly shown an intent for an early transfer to the South Korean military [6][9]. This is not a decision made out of consideration for the ROK-U.S. alliance. It is more likely the result of a convergence within the Pentagon between the need to redeploy forces in preparation for a Taiwan invasion scenario and the logic of readjusting the defense burden on the Korean Peninsula [12]. It is no coincidence that the review of reassigning 4,500 USFK personnel within the region emerged at the same time as the OPCON transfer discussions; it is a signal that America's force posture priorities are themselves being reorganized [12].

The context for General Brunson's emphasis on the urgency of implementing CJADO can be read in the same vein. He is making it clear that the transfer of command authority is not simply a matter of changing the insignia on the commander's uniform [1]. The substantive basis for his remarks is the concern that if the combined command structure is not redesigned based on an all-domain operational concept, a gap in operational capability could emerge even after command authority is transferred. His statement that political expediency should not override military readiness [1] shows that a gap already exists within Washington's military command between the pace set by the political line and the preparedness of working-level units.

2. Structural Context

Security StructureThe most fundamental constraint is the credibility of deterrence against North Korea's nuclear and missile threats. Even if OPCON is transferred to the South Korean military, the actual operational authority over extended deterrence remains with U.S. strategic assets. This asymmetric structure will not fundamentally change even after the OPCON transfer. Although the ROK-U.S. Nuclear Consultative Group (NCG), established through the 2023 Washington Declaration, has somewhat expanded South Korea's participation in decision-making, this amounts to an additional voice in the deployment and operation of extended deterrence assets, not a transfer of control [11]. The core of the structural tension is that the two tracks—OPCON transfer and the credibility of extended deterrence—are moving at different speeds.

Political StructureSouth Korea's ruling and opposition parties have formed a rare consensus on the OPCON transfer. This is demonstrated by the Democratic Party of Korea's leadership stating that strengthening independent defense capabilities is not contradictory to strengthening the ROK-U.S. alliance [20]. This marks a different phase from past debates on OPCON transfer, which were often framed as a conflict between the progressive camp's "self-reliant defense" and the conservative camp's "alliance strengthening." However, this consensus does not necessarily mean there is agreement on the specific conditions and timeline for the actual transfer. The defense minister nominee's reaffirmation of the "early transfer with no added conditions" and his dismissal of concerns about a perception gap with Washington [1] operate at the level of political rhetoric, not as an indication that the working-level verification process is complete.

Economic StructureThe 2027 defense budget, set at 73.27 trillion won (an 8.2% increase from the previous year), lends financial substance to the narrative of self-reliant defense [6]. However, how much of this increase is allocated to securing the independent command and control systems, intelligence assets, and surveillance and reconnaissance capabilities necessary for the OPCON transfer is a matter that requires separate verification. It should also be considered that the defense budget increase is not so much evidence of an accelerated transfer as it is a response to the Trump administration's pressure for greater defense burden-sharing [12][18].

Alliance StructureIt is important to note that moves to strengthen the functions of the United Nations Command (UNC) are proceeding in parallel with the OPCON transfer. The UNC is pursuing an organizational reform to consolidate its Armistice Agreement implementation and JSA security functions into a single brigade, an effort that is seen as linked to the prolonged stalemate in OPCON transfer negotiations [16]. It has not yet been clearly designed how the UNC's authority to manage the Armistice Agreement and its wartime operational control authority will be separated and coordinated after OPCON is transferred to the South Korean military. Because the legal signatory to the Armistice Agreement is the UNC Commander, the South Korean government's institutional means to block the strengthening of UNC functions are structurally limited [16]. This means that the post-OPCON transfer command relationship could become complicated, with a tripartite structure involving the UNC, the CFC, and the ROK Joint Chiefs of Staff.

3. Historical Precedents and Comparative Cases

The most direct precedent is the pattern of delays since the 2018 agreement. Under the principle of a conditions-based transfer, each administration has updated the verification items, institutionalizing the gap between the acceleration of political rhetoric and the actual pace of the handover [6]. It is too early to conclude that the recent remarks by General Brunson and the defense minister nominee's reaffirmation of an early transfer principle have completely broken from this pattern. In the past, similar expressions of political will have preceded action, but the military verification process failed to keep pace.

The case of command and control integration in the U.S.-Japan alliance offers a useful point of comparison. Japan has maintained independent operational control over its Self-Defense Forces (JSDF) from the outset, and under the U.S.-Japan Security Treaty, U.S. forces and the JSDF have parallel chains of command. The recent move by the U.S. and Japan to enhance interoperability by establishing a new JSDF Joint Operations Command and upgrading the command functions of U.S. Forces Japan [3] has proceeded not under the frame of a command transfer, but as an enhancement of this parallel command structure. Whereas South Korea's OPCON transfer deals with the handover of command authority itself, Japan's alliance transformation starts from the premise of independent command and focuses on strengthening the level of integration. This difference in starting points means that South Korea has limited models to refer to after the OPCON transfer. Even if the Future CFC adopts a structure with a ROK general as commander and a U.S. general as deputy commander, whether this can be stabilized in the same way as the U.S.-Japan parallel command structure is a problem that must be designed separately.

The progress of the Combined Joint All-Domain Command and Control (CJADC2) concept within the United States also serves as a relevant precedent. The U.S. Department of Defense has been pursuing this concept of linking the sensors and strike systems of all military branches for nearly 20 years, but technical and institutional integration has been continuously delayed [4]. Considering that CJADO is being presented as the Korean Peninsula version of this concept at the ROK-U.S. CFC level, there is a realistic constraint: it will not be easy to quickly implement an all-domain command and control system at the combined level when the U.S. military itself has not yet perfected it [4][7].

4. Key Variables Shaping Future Developments

The first variable is whether the review of USFK redeployment is actually executed. If the reassignment of 4,500 personnel within the region becomes a reality, the OPCON transfer discussion will enter a much more complex negotiating phase, combined with concerns about a force vacuum [12]. Conversely, if this review is put on hold, the political pressure for the transfer is also likely to ease.

The second variable is the timing and method of the UNC's organizational reform. There is a risk that the command relationship design could become tangled as the OPCON transfer and the strengthening of UNC functions proceed simultaneously [16]. If the two issues are not coordinated through separate channels, negotiating cards could get mixed up [16].

The third variable is the trend in the U.S. Congress regarding defense burden-sharing and deliberations on the budget for overseas stationing. As signs of desynchronization have already appeared between the Trump administration's presidential channel and the working-level channels of the Pentagon and CFC [16], the feasibility of statements related to OPCON transfer will vary depending on which channel they originate from.

The fourth variable is the pace at which the South Korean military secures its own surveillance, reconnaissance, and command and control assets required to implement CJADO. Whether the defense budget increase [6] is substantively invested in this area will be a key indicator of whether the gap between political rhetoric and actual transfer can be narrowed.