Table of Contents

The alliance between the United States and the Republic of Korea (ROK) is among the most successful in post–World War II history. It was crucial for defending the ROK during the Korean War and facilitated South Korea’s economic miracle by providing a crucial security umbrella. Over time, one could also assert that the alliance helped to foster democratization.

But the past is not prologue. It takes persistent effort to maintain and enhance the readiness of the alliance to deter a growing range of North Korean threats and to prevail should deterrence fail. Leveraging the alliance to serve a broader array of interests is an important but also an immensely challenging task. Since U.S. President Donald Trump took office in January 2017 and South Korean President Moon Jae-in assumed his post in May 2017, the two key allies have ventured into untested waters that could affect readiness postures.

The readiness of U.S. and ROK forces is being impacted predominantly by diplomacy and strategic alignment, U.S.-ROK alliance management, and the peninsula’s military balance. When the flurry of diplomacy with North Korea throughout 2018 prompted the cancelation and alteration of exercises and the rollout of various confidence-building measures (CBMs), these developments detrimentally impacted allied military readiness.1 Similarly important to maintaining readiness is the ability of each side to respond constructively to various challenges to alliance management, including the planned transition of wartime operational control (OPCON) from the United States to the ROK and tense negotiations over defense cost-sharing, among other factors. Meanwhile, the military balance on the peninsula remains dynamic. While the allies have altered their training exercises and other elements of their defense posture, the North Korean military has neither reduced its training nor stopped testing and fielding new weapons.2

The real challenge for the alliance lies in maintaining the highest degree of readiness amid rapidly evolving diplomacy in and around the Korean Peninsula and the critical tasks of alliance management.

The real challenge for the alliance lies in maintaining the highest degree of readiness amid rapidly evolving diplomacy in and around the Korean Peninsula and the critical tasks of alliance management. Ensuring that combined military capabilities and postures are not negatively impacted by these developments lies at the heart of preserving the high state of readiness and standards against which the alliance measures itself, a mentality captured by the slogan “Fight Tonight.”

Defining Readiness

Although diplomacy has reshaped the alliance’s military posture on the Korean Peninsula in certain respects, readiness remains an important standard for gauging the alliance’s effectiveness. The U.S. Department of Defense defines readiness as “the ability of military forces to fight and meet the demands of assigned missions,” an ability referred to here as “operational readiness.”3 A detailed and refined set of measures and metrics underpin readiness, centering on mission essential task lists that units at every echelon develop, train for, and use to assess their performance.4 These task lists are derived from plans, orders, and associated conditions and standards.

Commanders are responsible for evaluating their given unit’s operational readiness. While their overall assessments include a degree of subjectivity, their judgments are supported by many straightforward objective criteria. These factors include the health and fitness of their soldiers, vehicle maintenance, supplies on hand, training, and competencies set forth in service and joint doctrine. For example, soldiers are either able to use their weapons effectively or they are not. Similarly, units either have a given percentage of their tanks or ships ready or they do not. What all these aspects of operational readiness have in common is that they relate to the tactical and operational demands that military units must fulfill in the military theater to carry out the orders they are given.

Bryan Port
Bryan Port is a civilian strategist serving in the Department of Defense with significant experience on Korean security issues.

But operational considerations are not the only relevant facet of readiness. It can also be assessed in a more expansive, overarching fashion known as “strategic readiness.” This refers to the level of synchronization, or strategic alignment, between allies across a range of considerations. Normally, allies spend tremendous amounts of time developing a shared understanding of the security environment, defining strategic objectives, building threat assessments, designing the methods and initiatives required to achieve agreed-on objectives, and orchestrating actionable plans. It is essential to devote significant time to ensuring a high degree of alignment because if any element of alignment is compromised, strategic readiness is compromised.

The U.S.-ROK alliance is undergirded by a unique command-and-control structure consisting of four commands. The United Nations Command (UNC) was originally chartered to command and control all aspects of a coalition warfight. Upon the activation of the Combined Forces Command (CFC), UNC relinquished primary responsibility for commanding the overall warfight and came to focus on deterrence, maintaining the armistice, and managing the planning and integration of coalition forces for training and in times of conflict. United States Forces Korea (USFK) is responsible for ensuring that U.S. forces are trained and ready to perform their missions under CFC. In recent years, the ROK Chairman of the Joint Chiefs of Staff has moved from a role akin to the chairman in the U.S. system centered on advising the president and orchestrating the current and future direction of the overall joint force to assume a role that also includes command responsibilities over all ROK forces under armistice conditions and all ROK forces not directly subordinated to CFC in the event of conflict.

The Impact of Diplomacy on Readiness and Alignment

Diplomacy can reshape high-level strategic environments, and the Korean Peninsula is no exception. The ongoing diplomatic overtures South Korea and the United States are pursuing with North Korea pose challenges to the alliance’s readiness (see table 3).5 Even when military personnel can offset the impact of altered exercises or defensive measures in support of confidence-building efforts with the North Koreans, doing so carries near- and long-term opportunity costs.

Table 3. Downsized U.S.-ROK Military Exercises
Date Exercise
January 4, 2018 ROK and U.S. leaders agree to postpone ROK-U.S. combined training during the 2018 Winter Olympic Games.
April 1, 2018 ROK and United States begin Key Resolve (April 23–May 4) and Foal Eagle (April 1–26) combined exercises.
May 14, 2018 ROK and United States begin Max-Thunder training (May 11–25).
June 12, 2018 Trump pledges to halt military exercises at the Singapore summit.
June 19, 2018 ROK and United States announce the postponement of 2018 Ulchi Freedom Guardian exercise.
June 22, 2018 ROK and United States announce the postponement of Korean Marine Exchange Program.
July 10, 2018 ROK and United States annnounce the temporary suspension of Ulchi Freedom Guardian exercise.
October 19, 2018 ROK and United States announce postponement of Vigilant Ace.
March 2, 2019 ROK and United States announce “termination” of Key Resolve, Foal Eagle, and Korean Marine Exchange Program.
March 3, 2019 ROK and United States announce Ulchi Freedom Guardian will be replaced with smaller-scale command post exercise.
March 4, 2019 ROK and United States begin Dongmaeng command post exercise (March 4–12).
May 27, 2019 ROK holds Ulchi Taegeuk exercise (May 27–30).
August 5, 2019 ROK and United States begin second iteration of Dongmaeng command post exercise (August 5–20).
November 17, 2019 ROK and United States postpone a “combined flying training event,” successor to Vigilant Ace.
Sources: Various South Korean and U.S. newspaper articles (see endnote 5)

Impact on Short-Term Operational Readiness

The convergence of several political developments and diplomatic initiatives including inter-Korean negotiations, U.S.–North Korea talks, the impact of U.S.-China relations on Korean security, and South Korea’s own foreign policy initiatives could have significant implications for the alliance’s operational and strategic readiness. Relevant considerations include the possible weakening of interoperability due to fewer exercises, the potential politicization of threat assessments, alliance management frictions stemming from domestic politics that could be allowed to trump national interests, and a pressing need for the allies to design a new alliance strategy that accounts for a strategic environment and interests extending beyond North Korea. The U.S.-ROK alliance likely can weather and offset these near-term effects on both operational and strategic readiness by drawing on the high state of readiness they have built over time, and because military modernization efforts provide an added buffer.

Due to the security environment on the peninsula and the nature of the threat emanating from North Korea, the plans that undergird operational readiness are necessarily complex. This calls for rigorous training, especially through combined exercises, the most important of which have traditionally been the Key Resolve/Foal Eagle exercise (held late each spring) and the Ulchi Freedom Guardian exercise (held late each summer). Rigorous training, particularly for commanders and their staffs, is critical to the successful execution of operational plans. The high rate of turnover among U.S. forces on the Korean Peninsula further increases the importance of these two major annual theater exercises.

Operational readiness will continue to face hurdles if the compromises necessitated by diplomacy with Pyongyang continue, especially if an agreement on partially denuclearizing North Korea is reached, as that could cause joint exercises and other deterrence-enhancing measures to be reduced even more. It remains unclear if the Trump administration is going to reach some type of a nuclear accord with North Korea, a move the Moon administration clearly supports. But concluding any such denuclearization agreement with North Korea would entail extensive working-level negotiations, efforts to overcome major political hurdles in Washington and Seoul, and close coordination between the United States and the ROK. Another pertinent consideration is how North Korea and China would ultimately respond to a denuclearization agreement.

Impact on Long-Term Operational and Strategic Readiness

The overall impact of negotiations with North Korea on the near-term operational readiness of the U.S.-ROK alliance is not significant, but canceling, postponing, or severely downsizing joint exercises will have long-term operational and strategic consequences. These consequences could include delays in establishing alliance goals in the event of a major crisis. Although difficult to measure, a high degree of strategic alignment remains an essential factor in enabling the alliance to adjust to major political, diplomatic, and military developments. A weakened level of strategic alignment erodes readiness by delaying decisionmaking on strategic and operational issues, which in turn erodes the effectiveness of crisis management, combined responses to conflict below the threshold of major war, and combined warfighting.

For one thing, compensating for adjustments to readiness takes time and effort. Commanders and their staffs face constraints that impair the quality of planning and training, and this diverts time that could otherwise be spent on maintaining and enhancing readiness. Importantly, experienced military planners are in short supply. The inter-Korean Comprehensive Military Agreement could, for example, call on the staff that is planning for the adjustments of defenses in the Demilitarized Zone (DMZ) to shift the timing, duration, and substance of specific training regimens in ways that could have operational impacts.

The current negotiations with North Korea do not mark the first time diplomatic overtures with Pyongyang have had ramifications on readiness. The administration of former South Korean president Roh Moo-hyun (2003–2008) prioritized reconciliation with North Korea more highly and introduced the notion of a more self-reliant ROK defense posture.6 These policy stances led complex military planning and preparations to be altered, and it took significant efforts to recover from these changes when ongoing planning later resumed.

Similarly, the breakdown of the Agreed Framework in 2003 and North Korea’s first nuclear test in 2006 opened an entirely new frontier in assessing the North Korean threat.7 Sustaining a very high level of readiness became increasingly challenging for U.S. and ROK forces in the wake of these developments. This is because North Korea henceforth, at least theoretically, could use nuclear weapons against ROK and U.S. targets. Moreover, North Korea could conceivably threaten nuclear escalation to deter South Korea from responding militarily or to dissuade the United States from sending in reinforcements if hostilities were to ensue. The nuclear dimension also complicates how U.S. and ROK forces look at the asymmetrical threats North Korea poses.

Today, diplomacy with North Korea once again poses complications for strategic readiness. Maintaining strategic alignment does not happen in a vacuum: it is heavily influenced by political forces. This is particularly so in democracies like the United States and South Korea, where political leaders have to contend with public opinion and a delicate balancing of popular domestic programs against security and strategic imperatives. Election politics and transitions of administrations further complicate maintaining strategic readiness, particularly if there is a mismatch in fundamental political and strategic perspectives between the two administrations.

For Washington, Trump’s transactional mentality and ambivalence toward the U.S. alliance with Seoul has had a significant negative impact. Among his many statements on the need for alliances, Trump said that “If the United States believes that it doesn’t need an alliance with the Republic of Korea, I would say it’s ok. If the United States doesn’t want the alliance, we don’t have to beg for it.”8 This perspective is reflected in the U.S. position on burden sharing with the ROK. Even for the healthiest of alliances, burden sharing agreements are a sensitive political matter requiring significant political capital by both parties. While Washington and Seoul will reach a new Special Measures Agreement on how to share defense costs, the negotiations are going to be protracted and difficult.

But statements like those made by Trump undermine trust between alliance managers, lead to hedging behavior, and produce a transactional attitude that ultimately can weaken strategic alignment. The U.S. president has also denigrated the importance of joint exercises while emphasizing his close personal relationship with North Korean Supreme Leader Kim Jong Un. No stranger to juxtaposition, he has simultaneously lauded South Korea for being a major U.S. arms importer and underscored why it is important for the ROK to continue to buy more weapons systems from the United States.

During the first two and a half years of the Moon administration, a number of other important issues have heightened concerns among some U.S. alliance managers, such as South Korea’s specific positions on and goals for diplomacy with North Korea, military modernization priorities, seeming equanimity on North Korean provocations such as the testing of projectiles and rockets, and the direction of ROK-China relations.9 In certain quarters, there are concerns about Moon’s outreach to China and Seoul’s reactions to the diplomatic pressure Beijing exerted when South Korea allowed the United States to deploy Terminal High Altitude Area Defense (THAAD) radar arrays on the peninsula against China’s wishes. Some concerned parties feared that Moon would adopt the stance of his predecessor Roh that South Korea could act as a balancer between the United States and China, even though no such policy was enacted.10 While the ROK understandably has to cope with China as an immediate neighbor that boasts growing military and political capabilities, not to mention Beijing’s backing of Pyongyang, it is also important to bear in mind that the U.S. strategy is shifting increasingly in the direction of great power competition with China.

To be sure, the two democratic allies have very different historical trajectories and geopolitical experiences with respect to China, so Washington’s views on Beijing do not always align with Seoul’s. Nevertheless, there is a view among many observers in Washington that if Seoul veers too closely to Beijing, that would weaken the U.S. posture vis-à-vis China, raising fears that Beijing could exploit potential divergences between the views of South Korea and those of the United States. Moreover, such a move could also affect trilateral security cooperation between the United States, the ROK, and Japan.

Readiness and Alliance Management

Amid this confluence of pressing diplomatic issues, a common thread is the enduring challenge of durable alliance management. One major ingredient of managing relations between such allies is the series of meetings and other mechanisms that bring leaders from the two countries together. In the case of the U.S.-ROK alliance, major platforms include the annual Security Consultative Meeting led by the two countries’ defense ministers, the Military Consultative Meeting held between the two chairmen of the Joint Chiefs of Staff, and the Korean Integrated Defense Dialogue involving various high-level defense officials.11 These platforms and relationships are indispensable to maintaining alliance unity and coherence of action. Political leaders can enhance readiness by using these platforms to develop positions and approaches in advance of major decisions and summitry, rather than relying on them to implement decisions after the fact.

In 2018, the United States and the ROK used alliance management platforms primarily as implementing bodies and avoided more sensitive issues such as decisions on exercises and adjustments to the ROK’s force posture along the DMZ. Decisions were made at the political level, often with only tangential or subsequent consideration of strategic and military factors, forcing the alliance’s military leadership to try to limit the negative impact on security and readiness when implementing these political decisions. One high-profile example was Trump’s decision to cancel or alter military exercises, a decision that took both militaries and the ROK government by surprise. It is the prerogative of elected officials to choose to use alliance platforms in this manner, but doing so strains the alliance and degrades operational and strategic readiness.

The most visible change to U.S. and ROK military activities over the past year and a half was the alteration of the alliance’s major military exercises—namely Key Resolve/Foal Eagle and the Ulchi Freedom Guardian. Historically, the Key Resolve/Foal Eagle exercise included a command post and field exercise.12 The theater headquarters practiced the execution of operational plans, and units practiced combat maneuvers. In 2018, the allies altered the timing and scale of the exercises to deconflict with the Winter Olympics and to reduce tensions with North Korea. This trend continued in 2019 and the exercises were renamed Dongmaeng (the Korean term for alliance).13

Washington and Seoul went even further with the Ulchi Freedom Guardian exercise, which had been held annually each August, canceling it outright due to the June 2018 Trump-Kim summit in Singapore.14 Like Key Resolve, Ulchi Freedom Guardian, which focused on training theater-level headquarters, was crucial for training newly arriving personnel. This exercise also enabled the alliance to adapt and innovate in light of developments in North Korea and to integrate and optimize military modernization initiatives. Other joint initiatives were scrapped as well. Two Korea Marine Exchange Program exercises were canceled, as was Vigilant Ace, an annual December air exercise involving over 12,000 personnel and upward of 230 aircraft.15 Importantly, despite Washington and Seoul’s cancelation and alteration (reduction) of these major exercises, North Korea continued its own summer and winter training cycles unabated.

Views on the fallout of these cancelations have been mixed. Regarding the Ulchi Freedom Guardian exercise, the current commander of USFK, General Robert Abrams, stated that it was “a key exercise to maintain continuity and to continue to practice our interoperability, and so there was a slight degradation” in readiness.16 During his annual testimony to the Congress in April 2019, Abrams stated that overall, “we met all our training objectives. The biggest difference is we just don’t talk about it publicly.”17 Abrams cited eighty-two combined field training exercises since he took the reins. According to U.S. Army Pacific Commander General Robert Brown, off-peninsula military training also served as an offset to on-peninsula alterations.18 But other military experts have a different perspective. For example, (retired) Lieutenant General Thomas Spoehr at the Heritage Foundation stated that the “ability for higher level staffs to work and plan together has been impacted, as has the ability of U.S. based forces to flow to Korea.”19

In a tactical sense, Abrams is correct. U.S. and Korean forces can continue to draw on a high state of readiness built up through past exercises, provided units maintain a robust unit-level training program. However, the long-term operational and strategic levels have been affected as Spoehr intimated. The situation is likely to worsen. In June 2018, then acting secretary of defense Patrick Shanahan asserted that it is not necessary to resume major joint military exercises with the ROK.20 Moving forward, the allies reduced the scope, scale, and public profile of exercises.21 Current guidance to the U.S. military is to refrain from using the word “exercise” at all.22 Secretary of Defense Mark Esper and former chairman of the Joint Chiefs of Staff General Joseph Dunford view the current exercise program as sufficient, in effect formalizing the reduction in the exercise program.23

Exercises are important to both combat units and staffs that must build complex command-and-control proficiencies. In the context of the U.S.-ROK alliance, this task takes on the added dimension of building, maintaining, and enhancing relationships at all echelons and forging shared understandings of allied practices and capabilities. With the complex nature of the operational and strategic environment on the Korean Peninsula and high troop turnover, downsizing or skipping even one major exercise could have longer-term consequences, as a missed exercise cannot simply be made up. Those who miss an iteration of training suffer in terms of readiness, and to some extent pass on a decrement in readiness by way of the decreased efficacy of their turnover to those relieving them. Moreover, critical institutional memory is invariably weakened if major exercises are truncated, indefinitely postponed, or canceled.

There will be longer-term and critical consequences for strategic readiness if exercises continue to be curtailed or canceled. These effects will be magnified by the consolidation of USFK at Camp Humphrey’s. The move decreases the frequency and depth of interactions between the elements that have relocated and their counterparts on the ROK Joint Staff. Any large-scale relocation or reorganization of a large organization impacts efficiency and efficacy. That being said, assessing the strategic wisdom of relocation, the reorganization of command and control relationships, or the geopolitics of military exercises is beyond the scope of this analysis.

These readiness challenges would be pronounced enough if the alliance’s command structures were expected to stay static, but that is not the case. The changes in the chain of command that are planned add another wrinkle to ongoing efforts to maintain a high level of readiness. One of the most important issues for the Moon administration is efforts to hasten a long-planned change: the full reversion of wartime OPCON to the ROK as soon as both Seoul and Washington judge that the ROK has built up the requisite military capabilities. As of January 2020, the two allies are continuing their efforts to determine the timing and circumstances of wartime OPCON transition to the ROK. However, the efforts invested in this process require time, attention, and political capital that could be better invested in other issues.

During the tenures of former South Korean presidents Lee Myung-bak and Park Geun-hye, the allies decided that the reversion of wartime OPCON should be conditions-based rather than driven by an artificial deadline. Both sides gained by refocusing on enhancing capabilities directed at the North Korean threat and recalibrating command and control.24 The Moon administration, however, has prioritized more highly an expedited timeline for this handoff though it has not fully disengaged from conditions-based reversion. In August 2019, U.S. Secretary of Defense Esper and Minister of Defense Jeong Kyeong-doo held a defense ministerial meeting and affirmed “strides made toward the fulfillment of conditions for the transition of wartime [OPCON].”25 At the fall 2019 Security Consultative Meeting, they announced they will review the assessment of initial operational capability certification of the future CFC headquarters. To accelerate the handoff of wartime OPCON, the ROK and United States launched the Special Permanent Military Committee. The intended result is for an ROK four-star officer to assume command of CFC.26

Readiness and the Peninsula’s Changing Military Balance

The challenges to the readiness of the U.S.-ROK alliance would be significant enough if the North Korean threat was static, but it is not. Indeed, North Korea’s training regimens and exercises continue uninterrupted,27 and while it has refrained from testing long-range missiles, it continued to test a variety of short-range weapons systems and “niche capabilities” in the summer and fall of 2019, some of which qualitatively boost North Korean capabilities. Political leaders in Washington and Seoul asserted that these short-range weapons tests were not a significant threat and that they did not violate the September 2018 inter-Korean military agreement on CBMs. However, Pyongyang is essentially contesting alliance interests below the threshold of war since Kim knows that under the Trump and Moon governments, North Korea can continue to push the envelope without provoking a strong response.

If Kim launches a war, the United States and the ROK would be favored to win, although there would be massive destruction and the costs would be high.28 Such a scenario would be complicated enormously in the event of a major Chinese military intervention, calling into question whether the allies could win, at least in terms of the ability to set the conditions for Korean reunification. It is important to recall that less than a year after the People’s Republic of China was founded, the country’s leader Mao Zedong opted to send hundreds of thousands of Chinese troops to defend North Korea in the Korean War. Circumstances are very different today, yet an increasingly powerful China is again unlikely to sit on the sidelines in the event of major U.S. and ROK military operations across the thirty-eighth parallel.

That said, the North Korean military faces notable problems in training, logistics, and readiness in the face of the ROK’s much more advanced conventional forces.29 Yet despite these limitations and economic constraints, Kim has continued with select military modernization efforts such as upgrading the country’s submarine-launched ballistic missiles (SLBMs). The fact that North Korea today can strike targets throughout the ROK and Japan with increasing accuracy poses a growing strategic dilemma.30 For its part, South Korea understands that if North Korea’s SLBMs become fully operational, they would pose a key threat that the ROK military is focused on addressing.

Meanwhile, North Korea continues to criticize the ROK for undertaking its own military modernization efforts such as introducing F-35 fighter jets. But it makes eminent sense for South Korea to respond to a nuclearized North Korea in this way while abstaining from pursuing its own nuclear deterrent. Alliance military modernization is also an important endeavor in terms of meeting a spectrum of asymmetrical challenges from North Korea—such as cyberwarfare, chemical and biological weapons, and special operations forces—in addition to recalibrating defense postures to meet certain diplomatic requirements.

The ROK’s Military Modernization

Consequently, both allies continue to modernize their militaries. Under its 2020–2024 midterm defense plan, Seoul is investing in potent new military capabilities and bolstering existing operational capabilities. The ROK registered an impressive 8.2 percent year-on-year increase to its defense budget in 2019, and the midterm defense plan calls for sustained increases in defense spending, with important alterations in how funds are allocated. In particular, expenditures on force improvement programs will increase from 32.9 percent of the budget in 2019 to 38.2 percent in 2024.31 This modernization campaign is also designed to enhance interoperability and satisfy the ROK’s goal of expanding defense exports.32 These efforts have enhanced readiness to some degree.33

However, there is still room for improvement, as the magnitude of South Korea’s budget increases still has not kept pace with the security threats the country faces and its changing strategic environment. Further, ROK defense investments have prioritized weapons platforms, while underinvesting in enabling capabilities, such as communications equipment and munitions. Seoul has placed too little emphasis on systems integration within and between platforms, so the effects of the ROK’s military modernization to date have been less than the sum of its parts.

The ROK has not invested as efficiently as it could because Seoul places too much emphasis on reducing its perceived overreliance on U.S. systems and on increasing defense exports. This unbalanced, distorted approach has detracted from interoperability with U.S. forces. For example, while it is understandable that the ROK would prefer to develop its own missile defense systems, the time, capital, and talent allocated for developing such systems could be better applied to other pressing military needs, such as munitions or communications systems. After all, the ROK can purchase high-quality U.S. systems much more rapidly (years or decades faster) and at significantly less expense. The North Korean threat and South Korea’s shifting strategic environment do not allow the luxury of trying to make its military modernization serve so many purposes at once. None of this is to say that the ROK military is not making impressive strides because it undoubtedly is: yet these efforts and future ones would significantly benefit from greater focus and efficiency.

Like South Korea as a whole, the ROK military also faces daunting demographic challenges owing to a rapidly aging population and dropping fertility rate. The ROK plans to reduce its armed forces (especially the ground forces) by 100,000 troops by 2022, given the country’s rapidly falling birthrate.34 The ROK must seriously consider how best to allocate its defense resources given the looming specter of an increasingly powerful and aggressive Chinese military on top of the multiple threats that North Korea poses.

Meanwhile, the U.S. military is contending with its own challenges. In 2018, the U.S. military began to address serious readiness shortfalls (across its entire force structure) stemming from the prolonged War on Terror. U.S. Army Chief of Staff General Mark Milley tripled the number of brigade combat teams fully trained and ready to deploy.35 The Trump administration has undertaken a major military modernization campaign as outlined in the National Security Strategy and the National Defense Strategy.36 Additionally, the U.S. military continues to bring advanced capabilities to the ROK to address specific elements of the North Korean threat. Examples include THAAD, the Gray Eagle Unmanned Aerial System, and the F-35 joint strike fighter.37 Organizationally, USFK created an Emerging Capabilities and Innovative Effects Division to close remaining capability gaps and generate technological superiority.38

The United States has also focused on ensuring it can send additional troops to Korea and that the troops it has stationed there will perform effectively on the ground. Recognizing the inherent logistical challenges, the U.S. military has sought to make certain that it can deliver additional forces with greater lethality from the United States to the peninsula and nearby locations in a timely fashion. Additionally, these forces are meant to be a combat multiplier to ROK forces by forewarning of North Korean actions, and to elevate the readiness and lethality of ROK forces by providing intelligence, missile defense, strategic capabilities, and sophisticated command and control. U.S. modernization efforts also are designed to enhance force protection and enable the critical second-order effect of preserving combat power, particularly air power. Such combat capabilities can be used to neutralize North Korean artillery installations earlier in a potential conflict than would otherwise be the case.

However, as welcome as these advances in U.S. readiness are to South Korea, the strategic rationale for these efforts in Washington may provoke tensions with Seoul. This U.S. policy shift derives from national defense and national military strategies that address U.S. national interests globally and center on great power competition with China. This should concern the ROK, as it changes the context in which the United States will make military decisions moving forward. The United States and ROK should engage in private, candid consultations on how the alliance will serve both countries’ national interests beyond the North Korean threat and how each side understands and prioritizes those interests. At the same time, it is important for Washington to understand that, given China’s critical ties with North Korea, Seoul must pay greater attention to Beijing’s strategies and policies. Whereas the United States perceives China through a global lens with regional implications, Beijing’s shadow looms much larger over South Korea.

U.S. and ROK forces have achieved major milestones in improving interoperability and honing their capabilities especially following South Korea’s rapid economic growth over the past four decades. Today, the ROK military is an increasingly advanced and formidable force that can respond fully to a range of North Korean threats. Nevertheless, a nuclearized North Korea and much more complex geopolitical drivers in and around the Korean Peninsula have raised the bar for maintaining optimal readiness for the U.S. and ROK forces. Readiness is always a work in progress, and the challenges the ROK and the United States face at this particular juncture are without parallel.


Unity of purpose, command structures, and attention to strategic alignment are essential to the ability of both nations to maximize the value of the alliance. Although it is up to the political leaderships in South Korea and the United States on how best to engage North Korea while continuing to meet a range of asymmetrical threats, it is also important to bear in mind that any major erosion in strategic and operational readiness could have severe repercussions going forward. Most of all, retaining critical combined-joint capabilities, particularly interoperability, between the U.S. and ROK forces is crucial for ensuring a high level of readiness across the full spectrum of possible contingencies. Military readiness cannot be satisfied with other options or mechanisms or papered over for political purposes.

Military readiness cannot be satisfied with other options or mechanisms or papered over for political purposes.

To remedy this state of affairs, the allies should bolster readiness by: conducting theater-level combined training designed to ensure warfighting competencies remain intact, conditioning any transfer of OPCON on ROK command-and-control capabilities, maintaining the CFC with U.S. senior personnel stationed in Seoul, and establishing a secretariat to help oversee the alliance.

  • Resuming large-scale military exercises: Washington and Seoul should resume at least one large-scale exercise (like Ulchi Freedom Guardian, for instance) on the Korean Peninsula and begin a second exercise series involving significant ROK military participation off-peninsula. The off-peninsula exercise help enhance the ROK joint force’s command, control, and communications (C3) capabilities for conducting complex large-scale combat operations in a multinational environment.
  • Ensure that any transfer of OPCON remains conditional: The allies should return to a condition-based transition of OPCON to South Korea, with the central requirements for transition focused on the ROK’s C3 capabilities and its ability to command and control large formations in joint and multinational maneuvers.
  • Preserve the CFC: South Korea and the United States should maintain the CFC structure. Even if the U.S. four-star general becomes the deputy commander, he/she and the joint staff should remain in Seoul.
  • Establish a secretariat: The allies should establish such a body to complement the alliance’s already robust military command structure. A strategic alliance warrants a standing body of senior civilian and military leaders that can transcend day-to-day issues to ensure that the long-term foundations of the alliance remain strong and adaptable. There is simply too much at stake for both nations to allow the foundational institutions and relationships that led to the sacrifices and successes of the past seventy years to erode. Both nations have ample cause to invest in the alliance and expect it to provide a strategic return on investment in the decades ahead.

About the Author

Bryan Port is a civilian strategist serving in the Department of Defense with significant experience on Korean security issues. He has over a decade and a half of service in the Asia Pacific region, and he holds a master’s degree in national security studies from Georgetown University and a master’s degree in national security strategy from the National War College.

The analysis, opinions, and conclusions in this publication are the author’s own views and in no way reflect any views or positions of the United States, the U.S. Department of Defense, or any other offices in the U.S. government.


1 Mats Engman, “The Inter-Korean Military Agreement: Risk of War Diminished?” Institute for Security and Development Policy, November 2018,; and National Committee on North Korea, “Agreement on the Implementation of the Historic Panmunjom Declaration in the Military Domain” June 15, 2019,

2 Department of Defense, “Military and Security Developments Involving the Democratic People’s Republic of Korea: Report to Congress,” February 2018, 13,; and Oliver Hotham, “Kim Jong Un Oversaw Test of Short-Range Ballistic Missile on Saturday: KCNA,” NK News, May 5, 2019,; and “KN-09 (KN-SS-X-9), Center for Strategic and International Studies, July 10, 2017,

3 Department of Defense, “DOD Dictionary of Military and Associated Terms,” April 2019,

4 United States Joint Chiefs of Staff, “Joint Mission Essential Task List (JMETL) Development Handbook,” September 2002,

5 Table 3 is based on several U.S. and South Korean newspaper articles and other sources. See South Korean Ministry of National Defense, 2018 Defense White Paper (Seoul, South Korea: Ministry of National Defense, 2019),;

Nancy Cook, Louis Nelson, and Nahal Toosi, “Trump Pledges to End Military Exercises as Part of North Korea Talks,” Politico, June 12, 2018,; Dagyum Ji, “South Korea, U.S. to End Annual Key Resolve and Foal Eagle Military Drills,” NK News, March 2, 2019,; Dan Lamothe, “U.S. and South Korea End Military Exercises That Riled North Korea in Favor of Something Smaller,” Washington Post, March 3, 2019,; Jo He-rim, “South Korea-U.S. Kick Off Combined Exercise Dong Maeng,” Korea Herald, March 5, 2019,; “New Civilian-military Exercise Defensive in Nature: Defense Ministry,” Yonhap News Agency, May 27, 2019,; Nancy A. Youssef and Gordon Lubold, "U.S., South Korea Shelve Military Exercise in Bid to Break Nuclear Deadlock With North," Wall Street Journal, November 17, 2019,; and Kim Gamel and Yoo Kyong Chang, “U.S., South Korea Start Low-Key Joing Military Drills After North Korean Missile Tests,” Stars and Stripes, August 5, 2019,

6 Bruce E. Bechtol Jr., “The ROK-US Alliance During the Bush and Roh Administrations: Differing Perspectives and Their Implications for a Changing Strategic Environment,” International Journal of Korean Studies 9, no. 2. (Fall/Winter 2005): 87–117,; and Kim Min-seok and Ser Myo-ja, “Seoul Halts Joint Plan for North Collapse,” Korea JoongAng Daily, April 15, 2005,

7 Contemporaneous media accounts cite the primary issue raised by the Roh administration as concerns about infringement on Korean sovereignty. While perceptions on this issue were a primary driver in Roh administration positions, the author had extensive discussions with multiple ROK government officials who served in the Roh administration, and with Korean scholars, who have first-hand knowledge and cite concerns about the impact to Roh administration policy on inter-Korean relations as another key driver. Though not directly stated, this position can be discerned from multiple speeches that Roh delivered, including a speech in Los Angeles in 2004. See Ser Myo-ja, “Roh Calls for Softer Stance Against North,” Korea JoongAng Daily, November 14, 2004,

8 Uri Freedman, “America’s Alliance System Will Face One of Its Biggest Tests Yet,” Atlantic, May 23, 2019,

9 Based on the author’s professional experience. See also Tim Shorrock, “Washington’s Ire Shifts From Kim Jong-un to Moon Jae-in,” Nation, October 19, 2018,; and Tom Eck, “Two Years Into Moon Jae-in’s Presidency, What’s Been Achieved on North Korea?” NK News, May 13, 2019,

10 Zhu Zhiqun, “Small Power, Big Ambition: South Korea’s Role in Northeast Asian Security Under President Roh Moo-Hyun,” Asian Affairs, 34, no. 2 (2007): 67–86,; and Sung-mi Kim, “South Korea’s Middle-Power Diplomacy: Changes and Challenges,” Chatham House, June 2016,; and S. Nathan Park, “South Korea’s President May Be Just the Man to Solve the North Korea Crisis, Atlantic, July 18, 2017,; and Jung In-hwan, Seong Yeon-cheol, and Kim Ji-eun, “‘Balanced Diplomacy’ Becomes Fundamental to President Moon’s Foreign Policy,” Hankyoreh, November 6, 2017,

11 Alliance management and command structure in Korea are complicated. One of the very best and most succinct references available on the subject is this account. See Colonel Shawn P. Creamer, “Theater-Level Command and Alliance Decision-making Architecture in Korea,” International Journal of Korean Studies, 20, no. 2 (Fall/Winter 2016); and “US Says Wartime Control Transfer as Scheduled,” Korea Times, July 31, 2013,

12 Foal Eagle is the field element of the KR/FE series and larger in scale than Key Resolve. The 2017 FE involved 11,500 U.S. and 290,000 ROK personnel. See Ankit Panda, “Mattis: US-South Korea 2019 Foal Eagle Exercise to Be Reorganized,” Diplomat, November 22 2019,

13 Franz-Stefan Gady, “US, South Korea Kick Off Annual Military Drill Without US ‘Strategic Assets,’” Diplomat, April 3, 2018,; Barbara Starr and Jamie Crawford, “US, South Korea Scale Back Joint Military Drills ‘to Reduce Tension’ With North Korea,” CNN, March 3, 2019,; Helene Cooper, “Pentagon Again Suspends Large-Scale Military Exercises With South Korea,” New York Times, March 1, 2019,; and Kim Gamel, “N. Korean Criticism Raises Concerns That Scaled-Back Military Drills Have Reaped Little Payoff,” Stars and Stripes, April 25, 2019,

14 Tara Copp, “South Korea, US Cancel Ulchi Freedom Guardian Exercise for 2018,” Military Times, June 18, 2018,

15 Ankit Panda, “US, South Korea Call Off Foal Eagle and Key Resolve Exercises, Announce New Exercise,” Diplomat, March 4, 2019,; and Tara Copp and Aaron Mehta, “US, South Korea Suspend More Military Exercises,” Military Times, October 19, 2019,

16 Copp and Mehta, “US, South Korea Suspend More Military Exercises.”

17 Gamel, “N. Korean Criticism Raises Concerns That Scaled-Back Military Drills Have Reaped Little Payoff.”

18 Yeo Jun-suk, “Controversy Erupts Over US Suspension of Bomber Missions Over Peninsula,” Korea Herald, November 27, 2018,

19 Gamel, “N. Korean Criticism Raises Concerns That Scaled-Back Military Drills Have Reaped Little Payoff.”

20 Idrees Ali, “Acting Pentagon Chief Says No Need to Restore Suspended U.S.-South Korea Military Drills,” Reuters, June 2, 2019,

21 Kim Gamel and Yoo Kyong Chang, “US, South Korea Start Low-Key Joint Military Drills After North Korean Missile Tests,” Stars and Stripes, August 5, 2019,

22 Author discussion with Department of Defense official, September 2019.

23 Mark T. Esper and Joseph F. Dunford Jr., “Department of Defense Press Briefing by Secretary Esper and General Dunford in the Pentagon Briefing Room,” Department of Defense, August 28, 2019,

24 This is based on the author’s experience and perspective after serving at UNC/CFC/USFK from 2009 to 2017.

25 U.S. Department of Defense, “Readout of the Defense Ministerial Meeting Between the Republic of Korea and the United States,” August 9, 2019,

26 Jung Da-min, “Allies Launch Committee for OPCON Transfer,” Korea Times, April 20, 2019,; and Gabriel Dominguez, “South Korean General to Head Joint Military Command With U.S.,” Jane’s Defence Weekly, June 12, 2019,

27 Kim Yoo Jin, “North Korea Prepares for Annual Winter Military Exercises,” Daily NK, December 4, 2018,; and Choi Song Min, “Kim Jong Un Orders Army to Prepare for Combat,” Daily NK, March 14, 2017,

28 United Nations Command, Combined Forces Command, and United States Forces Korea, Strategic Digest 2018, 2018, 10–11,; and David E. Sanger and Choe Sang-Hun, “North Korea Tests New Weapon,” New York Times, April 17, 2019,

29 Mun Dong Hui, “Women Soldiers in North Korea Desert Post in Protest of Sexual Abuse,” Daily NK, May 21, 2019,; “North Korea’s Winter Parade Full of Cold, Beatings, and Exhaustion,” Daily NK, February 7, 2018,; “Prisoners in Uniform: NGO Reveals Human Rights Abuses in North Korean Military,” Daily NK, March 8, 2018,; and “Former Soldier Says 60% of North Korean Military Training Is Ideological ‘Brainwashing,’” Daily NK, March 9, 2017,

30 Geoff Brumfiel, “North Korea’s Newest Missile Appears Similar to Advanced Russian Design,” NPR, May 8, 2019,

31 Paek Jae Ok, “Structure and Policy Implications of the 2019 ROK Defense Budget,” Korea Institute for Defense Analysis, ROK Angle, no. 193, January 28, 2019; Lee Young-bin, “The 2020-2024 Mid-term Defense Plan for Realizing ‘Strong Military’ and ‘Responsible Defense,’” Korea Institute for Defense Analysis ROK Angle, no. 207, August 28, 2019. Both articles are available on the institute’s website:

32 Felix K. Chang, “The Rise of South Korea’s Defense Industry and Its Impact on South Korean Foreign Relations,” Foreign Policy Research Institute, April 22, 2019,

33 Paek, “Structure and Policy Implications of the 2019 ROK Defense Budget.”

34 “S. Korean Army to Curtail Forces by 100K Amid Shrinking Population,” Korea Herald, October 11, 2019,

35 David Vergun, “Army Readiness, Lethality Increasing Amid Troubled World, Says Chief of Staff,” U.S. Army, October 9, 2019,; and Corey Dickstein, “Milley: Army Is Still Years Away From Reaching Its Readiness Goals,” Stars and Stripes, October 10, 2017,

36 Meghann Myers, “In His Fourth Year, Army Chief Expands Focus From Readiness to Modernization,” Army Times, October 8, 2018,; Terry Moon Cronk, “Mattis: U.S. Military Becoming ‘Stronger, More Lethal, More Agile,’” U.S. Department of Defense, April 28, 2018,

37 United Nations Command, Combined Forces Command, and United States Forces Korea, U.S. Forces Korea Strategic Digest 2018, 2018,

38 Ibid.