The Present Value of USFK and South Korea’s Path Forward
- Commentary
- September 15, 2025
- Jaewoo JUN
- Research Fellow at the Korea Institute for Defense Analyses (KIDA)
Jaewoo Jun, an Associate Research Fellow at the Korea Institute for Defense Analyses (KIDA), provides a sweeping analysis of the evolving role of U.S. Forces Korea (USFK) within the broader currents of U.S. grand strategy and East Asian security. Tracing shifts from the Cold War through the present U.S.-China rivalry, Dr. Jun underscores that the ROK-U.S. alliance is not a static guarantee but a variable instrument of American strategic interests. The author highlights South Korea’s resulting structural dilemma and calls for a more rational, autonomous approach to alliance management that reflects both Seoul’s national power and the changing regional environment.
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Statements emphasizing the importance of U.S. Forces Korea (USFK) are repeatedly made by both the Republic of Korea and the United States. However, are the contexts in which Seoul and Washington stress this importance the same? If they differ, what would be the difference? Are the value and role of USFK fixed and unchangeable? This article traces the diachronic trajectory of USFK amidst the structural changes in the East Asian security environment to examine the adjustments of USFK. In particular, it focuses on the process that has led to South Korea’s structural dilemma within the current framework of U.S.-China competition.
The Essence of U.S. Alliance Policy: Realist Strategic Priorities
Before addressing USFK, it is necessary to understand the underlying motives driving U.S. alliance policy. The United States outwardly champions so-called ‘universal values’ such as democracy, human rights, and free trade. On the other hand, its foreign policy is underpinned by a paramount realist objective: maintaining its hegemonic status. Historically, all in the service of its national interest, the U.S. has repeatedly turned yesterday's enemy into today's ally, and today's ally into tomorrow's competitor. The clearest evidence of this fluidity can be found, without looking far, in the historical trajectory of U.S.-Japan relations.
In the early 20th century, the U.S. condoned and supported Imperial Japan's advance into the Korean Peninsula to counter Russian expansion.[1] However, when Japanese expansion in the Pacific clashed with American interests, Washington chose military confrontation and dropped the atomic bombs. After the war, to contain its former ally, the Soviet Union, the U.S. transformed Japan into a key bulwark in the Western Pacific, actively supporting its economic reconstruction and rearmament. In the 1980s, when Japan's economy reached nearly 70% of U.S. GDP, the U.S. deemed it a competitor and reined it in through the Plaza Accord. Then, as China emerged as a key challenger after the Cold War, the U.S. once again joined hands with Japan, elevating the U.S.-Japan alliance to a cornerstone of its strategy to counter China.
As this history shows, for the United States, an alliance is a strategic tool rather than a relationship based on values and norms. The U.S.’ threat perceptions and strategic goals of the era consistently redefine alliance’s value and role. The ROK-U.S. alliance is no exception.
U.S. grand strategy thus prioritizes the maintenance of its hegemony as the paramount objective. The method of this strategy is to suppress the rise of potential hegemonic rivals. From the perspective of this overriding strategic goal, USFK—stationed on the Korean Peninsula, a geopolitical fulcrum where the interests of the two Koreas and the four major powers of the U.S., China, Japan, and Russia intersect—functions as a key instrument. Consequently, the role of USFK has always been directly and continuously influenced not merely by the local context of inter-Korean relations, but by the far broader dynamics of U.S. hegemonic strategy and great power politics.
The Value and Variability of USFK during the Cold War: The Nixon and Carter Administrations
Having endured the ravages of the Korean War, South Korea signed a Mutual Defense Treaty with the U.S. in 1953. From its inception, the treaty embodied an asymmetric character, reflecting the divergent strategic calculations of the two states. From South Korea's perspective at the time, USFK was primarily perceived as a tripwire guaranteeing automatic U.S. intervention in the event of a North Korean invasion. From the American perspective, however, USFK was a geopolitical instrument with multi-layered objectives. Most importantly, it was a component of Washington’s global strategy of containment and deterrence against the Soviet Union.
Furthermore, USFK served to prevent adventurism by both North and South Korea on the peninsula. The ROK-U.S. alliance was also a crucial mechanism for alleviating the security anxieties of Japan—which feared being exposed on the front lines between the nuclear-armed U.S. and USSR. Therefore, the ROK-U.S. alliance ensured the stable, long-term presence of U.S. Forces Japan, the lynchpin of anti-Soviet containment in the Western Pacific.
While this basic security architecture in East Asia remained stable during the Cold War, the intrinsic dynamics of USFK fluctuated in response to shifts in U.S. threat perceptions and strategic environment. Mired in the Vietnam War, the U.S. felt a pressing need to partially ease the bipolar confrontation with the Soviet Union and pursue strategic stability based on a new balance of power. The critical opportunity for this strategic shift came with the Sino-Soviet split, which intensified in the late 1960s. The U.S. sought to leverage the split as a "golden opportunity" to create a favorable strategic landscape.
The Nixon administration and Henry Kissinger pursued a triangular diplomacy, first normalizing relations with China to pressure the Soviet Union, then pursuing détente with Moscow. The goal was to create a structure where the U.S. acted as the balancer in the Sino-Soviet conflict. This sophisticated diplomatic maneuver was not limited to reshaping great power relations. It was also strategically linked to achieving a favorable outcome in the negotiations to end the Vietnam War.
This shift in U.S. strategy directly led to a readjustment of USFK. After successfully improving relations with China, the Nixon administration judged that the possibility of a Soviet southward advance or a full-scale war on the Korean Peninsula became significantly unlikely. Despite President Park Chung-hee's vehement opposition, the administration withdrew the U.S. 7th Infantry Division in 1971 and repositioned the 2nd Infantry Division to the rear.
Subsequently, during the Carter administration, the U.S. repeated unilateral decisions regarding USFK. Carter advocated for the withdrawal of U.S. forces (specifically ground troops, after his election) during his presidential campaign. While ostensibly citing the Park regime's "human rights issues," the structural drivers for the withdrawal were the trauma of the Vietnam War and the political and economic turmoil in the U.S. caused by the first oil shock.
Ultimately, though they presented ostensibly different foreign policy platforms, both the Nixon and Carter administrations attempted to alter the status of USFK in line with America's strategic interests, even against South Korea's objections. This stands as a historical lesson: the posture and scale of the ROK-U.S. alliance and USFK are defined less by our will, the bilateral relationship, or the logic of the alliance itself, and more by the dynamics of great power politics and shifts in U.S. strategy.
The Decisive Turning Point: The 1992 U.S. Policy Reversal and Its Background
In the late 1980s, with the end of the Cold War, U.S. alliance policy in the region, including the role of USFK, faced a fundamental challenge to its raison d'être. Correspondingly, a re-examination of the role and scale of overseas forces began in the U.S. regarding South Korea specifically, there was a motive to reduce the burden of presence and the costs of alliance management. The initiative was further fueled by debates over U.S. responsibility for the tragedy in Gwangju in 1980, the subsequent democratization movement, and the perceived inequality of the Status of Forces Agreement (SOFA). America's own internal constraints, such as its massive twin deficits, and the alarm that Japan's economy had reached nearly 70% of U.S. GDP, provided further justification for these discussions.
The East Asia Strategy Initiative (EASI) arose against this backdrop. This initiative included the gradual reduction of USFK and a phased transition of operational control (OPCON). At the time, the U.S. Congress and security experts, acknowledging the growth in South Korea's defense capabilities, strongly demanded the OPCON transition. In the 1987 presidential election, both the ruling party candidate Roh Tae-woo and the main opposition candidate Kim Young-sam adopted the OPCON transition as their key campaign pledge. U.S. Secretary of Defense Dick Cheney's visit to Seoul in 1990 to demand an early transition of peacetime OPCON further amplified this trend.
The EASI was detailed in the Department of Defense’s 1990 official report to Congress, titled “A Strategic Framework for the Asian Pacific Rim: Looking Toward the 21st Century.” The report outlined a three-phased, decade-long plan to gradually reduce U.S. forces in the Asia-Pacific and increase the burden-sharing of allies including South Korea and Japan.
However, this plan reached a decisive turning point in the early 1990s amidst a rapidly changing security landscape. In May 1992, General Robert W. RisCassi, then-Commander of the ROK-U.S. Combined Forces Command, abruptly halted the discussions on the OPCON transition. This was not a personal decision but an official reversal of U.S. policy. The combination of the following factors led to this shift:
First, the strategic value of the Asia-Pacific region increased. Following the end of the Cold War, the world's political and economic center of gravity was shifting from Europe to the Asia-Pacific. Ensuring free trade and hegemonic stability in this region was a core U.S. national interest. The withdrawal of U.S. forces from the Philippines further increased the relative value of USFK and U.S. Forces Japan. U.S. experts assumed that a withdrawal of USFK would trigger a chain reaction affecting the presence of U.S. forces in Japan.
Second, China rose as a new hegemonic competitor. In the late 1980s, the U.S.’s main concern was Japan’s economic might. But from the early 1990s, China began to increase its military capacity based on the success of its reform and opening. From Washington's perspective, China was beginning to be perceived as a new potential hegemonic rival to replace the Soviet Union. To counter China’s potential expansionism, maintaining military control and influence over the geopolitical fulcrum of the Korean Peninsula was essential.
Third, the U.S. grew concerned over the North Korean nuclear program and South Korea’s potential unilateral action. North Korea was diplomatically isolated after Seoul established diplomatic relations with Moscow and Beijing, while Pyongyang failed to normalize its ties with Washington. This isolation led to North Korea’s pursuit of nuclear development. In response, South Korea's then-Minister of Defense Lee Jong-koo hinted at a strike on North Korea's nuclear facilities in April 1991. From Washington's viewpoint, such a remark signaled the possibility of a South Korean preemptive strike, sending shockwaves through the U.S. policy establishment. One of the U.S.’ fundamental reason for securing OPCON over the ROK military in the 1954 Agreed Minute was to prevent entanglement in South Korean unilateral actions, such as an advance toward the North. In a similar context, the inter-Korean dynamics of the early 1990s became a catalyst for the U.S. to enhance its control.
Fourth, the U.S. observed that North Korea could collapse after losing its primary patron, the Soviet Union. Should North Korea collapse while OPCON was held by South Korea, it was possible that South Korea would unify the peninsula. This possibility could have weakened or eliminated the justification for USFK's presence. Combined with South Korea's democratization, the U.S. feared a situation similar to the 1991 Philippines scenario, where U.S. forces were completely withdrawn from the country.
Fifth, anti-American sentiment in South Korea declined. Following the 1987 democratization movement, the South Korean government secured its legitimacy through a direct presidential election. This in turn weakened the momentum of the democratization movement in South Korea. As a result, there was a significant reduction in the costs of alliance management and the burden of U.S. presence. In fact, the U.S. concept of separating peacetime and wartime OPCON in 1994 was in response to accusations that the U.S. was behind the actions of ROK military units under its OPCON during the 1979 coup and the 1980 Gwangju democratization movement.
As these factors converged, the original plans from the first EASI report were completely discarded. Instead, the U.S. began to re-evaluate and readjust its regional forces, including USFK, as core assets to counter China. The planned force reductions and phased withdrawal were halted, and policy pivoted back toward re-emphasizing the importance of the U.S. presence in Asia. If U.S. forces were to remain on the peninsula, exercising OPCON over the ROK military was deemed essential to maximize their efficiency and control. This post-1992 policy reversal by the U.S. was the decisive moment that placed the ROK-U.S. alliance firmly on a trajectory deeply entangled with America's hegemonic strategy.
Consequently, the OPCON transition that had been underway since the late 1980s was suspended. For the next decade, the U.S. embarked on a plan to readjust the posture of USFK. The corresponding decision was to consolidate dispersed USFK units into Camp Humphreys in Pyeongtaek, facing China. During the process, the U.S. clandestinely pursued the creation of a "Northeast Asia Command (NEAC)," which would have integrated USFK, U.S. Forces Japan, and the 7th Fleet. Although it was never established due to South Korean opposition and inter-service rivalries within the U.S. military, it could be interpreted as the prototype for the later concepts of an integrated ROK-U.S.-Japan structure, a "one theater" concept, and the issue of "strategic flexibility" between the ROK and the U.S.
Thus, the U.S. pivot in the early 1990s to restructure its forces to counter China was the decisive turning point that altered the character of USFK. From this moment, South Korea was exposed to a dual security dilemma: the risk of its security being entangled in the front lines of a U.S.-China conflict and the risk that USFK's primary mission of deterring North Korea could be weakened under the concept of "USFK's strategic flexibility," This fundamental strategic divergence over the alliance's objectives and USFK's role remains an unresolved issue despite continuous consultations between Seoul and Washington.
Some trace the origins of the USFK’s “strategic flexibility” debate to the early 2000s, initiated by the 9/11 terrorist attacks and the ‘Rumsfeld Doctrine.’ The explanation emphasizes the U.S.’s need to adjust USFK’s operational concept not to directly target a single hegemonic competitor, but to respond to the demand for military interventions arising worldwide, including in the Middle East. An extension of this view argues that the South Korean and U.S. governments began to discuss the USFK’s strategic flexibility around 2003, and reached an agreement in 2006. This argument interprets the 2006 joint statement between then-Foreign Minister Ban Ki-moon and U.S. Secretary of State Condoleezza Rice and an intergovernmental memorandum of understanding (MOU) as the basis of that agreement.
However, while such interpretations of the origins and the ‘agreement’ are true individually, it is important to note that attempts to establish an integrated model originating from the Far East Command (FECOM) and the changing nature of the US Forces Korea have repeatedly emerged in various forms since the 1950s. The decisive adjustment positing China as a potential hegemonic competitor can be traced to the early 1990s. The adjustment went beyond a conceptual stage, as the phase involved actual partial adjustments to USFK's force size and OPCON over the ROK military.
Therefore, from that point onward, the context of USFK’s presence in the region should be linked to U.S.-China strategic competition. The major issues in the ROK-U.S. bilateral relations should be interpreted as structural extensions from that period. The case of 2006 may be a diplomatic expression of mutual ‘respect’ on the issue, or a temporary mending of differences. However, the view that it reflects a substantive agreement would be inaccurate.
Conclusion: Recommendations for Our Security Strategy
The historical trajectory of USFK outlined above clearly reveals the limitations of public discourses on the matter. The public discourse has reduced the function of USFK and the essence of the ROK-U.S. alliance to a purely local, inter-Korean framework while treating it as a static entity. This report calls for a fundamental reconsideration of these views. The argument made in certain circles that "an OPCON transition will cause the collapse of the combined readiness posture, including the withdrawal of USFK" is a flawed causality that fails to grasp the realist nature of U.S. alliance policy. In essence, USFK and U.S. alliance policy are instrumental in character, designed to implement America's global strategy. The continuation and role of U.S. alliance policy, including USFK and the ROK-U.S. alliance, are subordinate variables serving the objectives of U.S. national interest and strategy. They are not fixed entities, as they are subject to change based on strategic circumstances.
Current U.S. alliance policy is in a fluid, transitional state, oscillating between the integrated deterrence strategy pursued by previous Democratic administrations and the “America First” principle of the Trump administration, with its demands for selective intervention and an expansion of allies' primary roles. Under Secretary of Defense for Policy Elbridge Colby has proposed a force restructuring concept in which USFK’s mission would focus more on countering China, while the ROK military’s role would concentrate on conventional defense against North Korea. Some U.S. think tanks are also arguing for the reduction of USFK, citing the need to operate U.S. forces in other parts of the region. This trend cannot be reduced to mere policy differences between administrations. It is more accurately interpreted as a transitional phenomenon emerging from a more fundamental factor: a deepening structural divergence.
Today, the changing nature of the alliance and USFK presents South Korea with a structural dilemma, yet public discourse on this issue remains relatively constrained. A social atmosphere that treats the alliance as a kind of static entity and sanctity, could forbid rational debate and critical examination on the matter. It poses a great risk of shackling our strategic options in a changing security environment.
According to media reports, during recent ROK-U.S. tariff negotiations, the United States demanded that the South Korean government publicly declare and support the idea that USFK’s role is to deter not only North Korea but also China. In contrast, at a press conference aboard the presidential plane just before the ROK-U.S. summit on August 24, President Lee Jae Myung remarked to the effect that it would be difficult to easily agree to such a U.S. demand. This serves as corroborating evidence that both sides recognize that the debate over USFK’s scale and operations is fundamentally rooted in the structural factor of U.S.-China strategic competition. The core structural features of the present, which contrast with the past, can be summarized in two points.
First is the shift in America’s primary strategic competitor from the Soviet Union to China, and the fundamentally different nature of Chinese expansionism compared to that of the Soviet Union. Soviet expansionism presupposed a southward advance on the Korean Peninsula, which necessitated a force posture geared toward large-scale ground warfare. The ROK military was also built primarily with North Korean ground forces in mind. The ROK-U.S. alliance and USFK were built upon this geopolitical and military-strategic understanding. In contrast, China's expansion is occurring through power projection centered on its naval and air forces in areas like the East and South China Seas. As a result, a strategic divergence has emerged between the existing ROK-U.S. posture and the nature of the Chinese expansion that the U.S. now confronts.
Second is the change in the character of the patterns in OPCON transfer. During the Cold War, discussions on strengthening the ROK military’s autonomous capabilities and the OPCON transfer mainly occurred during the periods of great power détente. In contrast, the current discussions are taking place in parallel with the intensification of U.S.-China competition. This is part of an effort to bridge the aforementioned structural divergence, stemming from the necessity for South Korea to play a more leading role in securing battlefield management capabilities on the Korean Peninsula.
Therefore, South Korea needs to emphasize that it fully recognizes the structural interests of the United States and that the strengthening of the ROK military’s autonomous capabilities does not conflict with America’s strategic interests. In this process, the U.S. may be tempted to exercise control in proportion to the ROK military's capacity growth. However, Seoul must persuasively communicate that, considering South Korea's international status and military capabilities, a control model based on a minimal residual U.S. force is not realistically sustainable.
Furthermore, it must be stressed that, unlike in the past, strengthening the ROK military’s capabilities now alleviates the U.S. burden. It should also be noted that South Korea’s increase in defense spending and the OPCON transfer are inextricably linked. The issue of alliance burden sharing also requires emphasizing a plan premised on OPCON transfer. If possible, linkage to issues of high strategic value, such as the easing of restrictions on spent nuclear fuel reprocessing, could also be considered.
Above all, the entire process of redefining the alliance into a more rational relationship befitting our national power and status must be underpinned by a dedicated national effort to cultivate the public's understanding of security and history. ■
[1] This in itself is a historical example of the United States completely reversing its established position on the Korean Empire—a position set by the 1882 Treaty of Amity and Commerce—in accordance with its own interests.
■ Jaewoo JUN is a Research Fellow at the Korea Institute for Defense Analyses (KIDA).
■ Edited by Inhwan OH, Senior Researcher Fellow; Jonghyuk CHUNG, Researcher, Korea National Diplomatic Academy
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