OPCON Transition: Now It Is Time for the Commanders-in-Chief

The debate over wartime operational control (OPCON) transition once again stands at the threshold of decision. At the 57th Security Consultative Meeting (SCM) in 2025, South Korea and the United States agreed to pursue verification of the full operational capability (FOC) of the Future Combined Forces Command headquarters in 2026, and the 2026 U.S. National Defense Strategy (NDS) assessed that South Korea is capable of taking primary responsibility for deterring North Korea with “critical but more limited” U.S. support. More than 20 years have passed since the allies formalized OPCON transition, and more than a decade of preparation and verification has accumulated since they adopted the conditions-based transition plan. Meanwhile, South Korea has grown into an ally with military and economic capabilities entirely different from those it had when this arrangement was created some 70 years ago. With the next SCM approaching, the question must change. Until now, the debate has centered on asking: have the military conditions been met? The purpose of a conditions-based approach was not to avoid a decision, but to make a responsible decision possible. Military preparation always carries residual risk, and from the moment one judges what level of risk is acceptable, the question moves beyond military assessment into the realm of political responsibility. Whose Decision Is It? The wartime OPCON exercised by the commander of the ROK-U.S. Combined Forces Command derives from two sources. For U.S. forces, this authority is delegated through the chain of command from the U.S. president, through the secretary of defense, to the combatant commander. For South Korean forces, it is delegated under the South Korean president’s authority as commander-in-chief. OPCON transition, then, is neither a one-directional “return” of operational control nor simply a change in military structure. It is a political decision by the two commanders-in-chief to delegate their respective authorities to a new structure. This distinction matters. If transition is seen as South Korea’s demand alone, the United States becomes the examiner and South Korea the examinee. If it is seen as a joint decision of the two commanders-in-chief, both sides have things they must do to make the decision possible. What OPCON transition needs, therefore, is not only the military authorities’ assessment of conditions, but a responsible decision by the supreme commanders, the presidents of South Korea and the United States. The political tasks for transition can be sorted into four lines of effort. They are tasks the two countries’ political leaders must carry out, and at the same time political criteria for agreeing on transition at the summit level. 1: Understand and Address Military Concerns The vulnerability of a transition period cannot be denied. Viewed from a purely military perspective, OPCON transition can only be postponed indefinitely, for a perfectly prepared military does not exist. Yet denying it only deepens distrust within the alliance. What is needed is for the two countries’ political leaders to jointly acknowledge this vulnerability, and to offset and manage it with alliance-level political-strategic means alongside military compensating measures. The starting point is understanding that the two sides’ concerns differ. South Korea’s concerns converge on the credibility of extended deterrence, the deployment of reinforcements in a contingency, and a command gap during transition. On the U.S. side, the main concerns are possible degradation of the combined defense posture, the institutional and political problems of U.S. forces operating under a South Korean general, and the risk perceptions of the Combined Forces Command and parts of Congress. The South Korean president must demonstrate, through exercises and verification, that South Korea has a working crisis decision-making structure to lead theater operations, running from the president to the Ministry of National Defense, the Joint Chiefs of Staff, and the Future Combined Forces Command. The U.S. president must reaffirm the defense commitment and extended deterrence at the summit level and continue institutionalization through the Nuclear Consultative Group. The scope and procedures of the bridging and enduring capabilities the United States will provide should be codified in the relevant agreements and strategic directives. The NDS’s reference to “critical but more limited support” needs to be fleshed out with specifics. There are also things the two countries must do together. Whether to accept or limit escalation in a crisis, and under what conditions to begin and to end a war, are matters for the commanders-in-chief to judge. The two leaders must therefore identify and align, in peacetime, their perceptions of war aims, escalation thresholds, and war termination conditions. The allies should also adopt a “No Surprise” principle: changes in posture, command reorganization, and the movement of forces in and out must be consulted in advance. 2: Commit Resources and Assets Continuously A decision not backed by the necessary resources is no more than a political declaration. The investment South Korea must bear is considerable, but what is needed is not money alone. It also includes the commitment of national capacity for the employment and posture of military forces. Both sides need multiyear, bipartisan commitments that can survive changes of government. South Korea must link its roadmap for core military capabilities to the Mid-Term Defense Plan and secure its sustainability through the National Assembly. Recent defense spending increases should be explained not as burden-sharing, but as part of the national goal of transition and independent capability. The United States must back the assets, posture, and budget needed to provide bridging and enduring capabilities, such as intelligence, surveillance, and reconnaissance (ISR), space, strategic asset deployment, and reinforcement plans. A responsible answer by the administration to the National Defense Authorization Act provision concerning transition-related funding and certification is also part of this effort. South Korea’s commitment of resources becomes the basis for a capability-based voice within the alliance. The U.S. commitment of assets ensures that “limited support” is never read as “uncertain support.” OPCON transition is not a single event, but part of a process of completing a future-oriented combined command structure – one that the legislatures and executive branches of both countries must resource together. 3: Develop a Future-Oriented Alliance Architecture Security and alliance issues must not be treated as transactions, like trade negotiations. If OPCON transition is transactionally linked to other issues, it becomes something obtained by paying a price. This can fuel political backlash against transition in both countries and damage trust in the alliance. Defense cost-sharing, reductions in U.S. Forces Korea, and the Northeast Asia Command concept could all become subjects of such transactional linkage. These issues are not entirely unrelated to OPCON transition, but they must be handled on separate tracks and must not become terms of exchange. For the U.S. president, policy alignment within the administration is needed above all. Within Washington, OPCON transition can be viewed through the White House’s alliance policy and negotiations, the defense establishment’s burden-sharing, and the combatant command’s command relationships. Aligning these into a single strategic direction is a task only the commander-in-chief can perform. The South Korean president, for his part, should not make out-of-area contributions a term of exchange for progress on transition. Leading the defense of the Korean Peninsula and making selective contributions in the Indo-Pacific are separate matters, each under its own principles. At home, OPCON should not be consumed merely as a symbol of sovereignty. The two countries can begin by describing these issues separately in official documents such as the SCM joint communiqué. Of course, not every link can be cut. Command relationships among the Future Combined Forces Command, the United Nations Command, and U.S. Forces Korea, access to United Nations Command rear bases in a contingency, and the alliance’s regional role cannot be thought of apart from transition. Transactional linkage and structural linkage must therefore be clearly distinguished. Structural linkage should not be hidden or postponed, but discussed transparently and established together in designing the transition. 4: Take Responsibility for and Explain the Political Decision If OPCON transition is not made by military judgment alone, responsibility for the decision should not rest on the military alone either. The military assessment that “the military is ready” and the political judgment that “the two governments have decided” must be kept distinct. Otherwise, when problems arise, responsibility shifts to commanders, and political leaders hide behind military outcomes. The U.S. Congress is already involved through the National Defense Authorization Act, overseeing whether conditions are met, the Future Combined Forces Command’s national command reporting chain, the relationship with the United Nations Command, the impact on nuclear proliferation, and military risk. If the administration does not answer these questions systematically, caution in Congress and in the field will delay the decision at the working level. The South Korean National Assembly, by contrast, has no equivalent procedure. As the body that must provide the budget and institutional arrangements, it should be involved through regular reporting and verification, and the executive branch must explain why transition needs to happen now, what changes and what does not, and what is required. Political accountability also includes the management of trust. South Korea must not treat transition only as a political timetable and neglect military preparation, nor give that impression. The United States should refrain from messages suggesting that the Combined Forces Command could be dissolved if conditions are not met. That, too, is part of the responsibility for completing an agreement the two countries have pursued together for 20 years across administrations. The Politics of Decision and Responsibility In the end, the last gateway of OPCON transition is not military assessment alone but the responsible political judgment of the two commanders-in-chief. For 20 years, military assessments have often provided grounds for deferring political decisions. What is needed now is not to keep asking whether the conditions have been met, but for the commanders-in-chief to decide and to take responsibility for that decision. That means four lines of effort: identifying and managing the military risks of transition; continuously providing the resources and assets to support it; designing the future alliance’ command structure together rather than treating transition as a transaction; and explaining the decision to the public and the legislature and taking responsibility for its results. These are not South Korea’s homework alone. If only one side carries out these steps, transition remains one side’s demand or a one-sided transfer of burden. Only when carried out together do they work as political criteria and as a driving force. OPCON transition is not an event that settles the past, but a process of jointly designing the alliance’s future command structure – and completing that design is, in the end, the commanders-in-chief’s responsibility.