Table of Contents

South Korea faces a precarious security environment with an imposing nuclear-armed rival on its doorstep. The conditions of preserving the country’s security have only grown more demanding as North Korea’s arsenal and other military capabilities have matured. As an added wrinkle, ties between Seoul and Washington are as contentious as they have been in recent memory. The longtime allies are locked in a protracted dispute over cost sharing and beset by the challenges of coordinating diplomacy with interlocutors in Pyongyang who seem less inclined to make concessions than diplomats in Seoul or Washington would wish.

Yet, amid this flurry of priorities, it has become more, not less, necessary for the Republic of Korea (ROK) military to maintain a high state of readiness and interoperability with U.S. forces. A host of factors will decide how successfully Seoul balances these competing imperatives. For starters, the ongoing nuclear talks with North Korea remain the most direct way to curb North Korea’s nuclear ambitions, even if hopes of a tangible diplomatic breakthrough seem increasingly bleak. Yet while the concessions that South Korean President Moon Jae-in and U.S. President Donald Trump have made to keep talks on track have resulted in some minor tangible tradeoffs, what has happened is that readiness has been sacrificed to avoid giving North Korean Supreme Leader Kim Jong Un a pretext for walking away from the table.

Canceling crucial exercises could detract from Seoul’s very ability to manage the threatening neighbor it is engaging with by downgrading South Korea’s military readiness and compromising its ability to conduct operations with U.S. forces. Meanwhile, the future of the alliance’s very foundation is exposed to swirling uncertainties over long-term cost-sharing arrangements and the command structure of combined U.S.-ROK forces that would issue orders if conflict were to resume.

Canceling crucial exercises could detract from Seoul’s ability to manage its threatening neighbor . . . by downgrading South Korea’s military readiness and compromising its ability to conduct operations with U.S. forces.

For its part, South Korea is undertaking an ambitious slate of defense reforms to keep its conventional military edge despite various challenges. The degree to which these reforms and a renewed sense of purpose for the U.S.-ROK alliance can make the difficult terrain ahead easier to navigate will help determine how effectively the Moon administration can provide for the national defense through the end of its term in May 2022. The stakes could hardly be higher for South Korea, the United States, or the security of Northeast Asia at large.

How Nuclear Talks Are Affecting Readiness and Interoperability

Since Moon took office in May 2017, Seoul has stressed improving ties with North Korea in hopes of promoting peace on the Korean Peninsula and more broadly in Northeast Asia. While this peaceful overture has eased diplomatic strains to some extent, it has produced few if any tangible signs that Pyongyang would relinquish its nuclear arsenal.

In April 2018, Moon and Kim signed the Panmunjeom Declaration. They agreed to work together to reduce sharp military tensions, avoid war, and try to build an enduring peace regime between the two Koreas.1 As for the nuclear dimension of the talks, the two sides acknowledged the common goal of completely denuclearizing the Korean Peninsula with support and cooperation from the international community.

Shin Beomchul
Shin Beomchul is a former senior fellow at the Asan Institute for Policy Studies. He is an expert on Korean security, North Korea’s military strategy, and the ROK-U.S. alliance.

From the onset, however, North Korea’s definition of denuclearization has differed significantly from U.S. views. Washington insists that the end goal is the complete dismantlement of all aspects of North Korea’s nuclear weapons program. While the U.S. government would consider interim steps that move toward that end, its position leaves no room for Pyongyang to retain even a small nuclear arsenal.

North Korea, meanwhile, has maintained that it will never give up its nuclear weapons unless the United States takes reciprocal steps such as removing the nuclear umbrella over South Korea, stopping the introduction of all strategic assets including bombers that could deliver nuclear warheads to the peninsula, and making assurances that Washington would end all its supposedly hostile policies toward Pyongyang. Any concessions that the North Korean government did express a willingness to make, such as the dismantlement of the Punggye-ri nuclear test site in late May 2018, were not meaningful steps toward genuine denuclearization.2

Throughout 2018 and into 2019, both Moon and Trump held a flurry of summits that raised hopes of a diplomatic resolution in media circles but produced quite modest results. Trump first met with Kim in June 2018. At the Singapore summit, the two leaders released a joint statement that affirmed general principles of the Panmunjeom Declaration but lacked details on specific commitments or timelines. The two sides agreed to work toward a stable peace regime, with Trump agreeing to “provide security guarantees to North Korea,” and Kim reaffirming, at least on paper, his “firm and unwavering commitment to [the] complete denuclearization of the Korean Peninsula.”3 In the end, the meeting was short on substance, produced no tangible progress on denuclearization, and only highlighted the vast gap between rhetoric and reality.

Nevertheless, within months, Moon held another summit with Kim in September 2018 to outline and formally commit to confidence-building measures (CBMs) based on the Panmunjeom Declaration. This was the second of three inter-Korean summits under Moon and the fifth overall occasion of its kind since the first South-North summit in 2001 between then president Kim Dae-jung and then North Korean leader Kim Jong Il. At the September 2018 meeting, the two sides formally agreed to keep communication channels between the two Koreas open, to implement the agreement together, and to prevent accidental military clashes through CBMs.4 Yet, once again, North Korea pointedly refused to provide a detailed roadmap on denuclearization.

To try to break this impasse, Trump met Kim again in Hanoi in late February 2019. Despite high expectations, the summit did not result in any substantive progress. Trump later intimated that North Korea had demanded blanket sanctions relief without meaningful forward movement on denuclearization, a clear nonstarter for Trump.5 However, then North Korean foreign minister Ri Yong Ho disputed that account and insisted that Pyongyang desired only partial sanctions relief and that it was U.S. negotiators who had overreached on their demands.6

Trump and Kim held a third, albeit symbolic, meeting in late June 2019 that proved to be more of a photo op than a hard-nosed negotiating session. Despite iconic photos of Trump crossing the Military Demarcation Line (MDL) at Panmunjeom to shake hands with Kim, progress remained stubbornly absent. The two leaders agreed to begin working-level negotiations on denuclearization but without designating specific timelines. The Hanoi and Panmunjeom meetings between Trump and Kim revealed two leaders that had both overestimated their ability to convince the other to offer concessions. The meetings also showed the limits of highly personalized summitry. Chemistry between individual leaders obviously matters, but it cannot be a substitute for significant progress at the working level. Moreover, North Korean authorities never affirmed Trump’s rhetoric and exaggerated accounts of what he had agreed to with Kim.

Overall, it remains doubtful whether North Korea intends to denuclearize. Pyongyang seems to want to retain most of its nuclear capabilities while also receiving sanctions relief. In contrast, the United States continues to favor final, fully verifiable denuclearization, a watered-down variation of the previously stated goal of complete, verifiable, and irreversible dismantlement. Since the failed Hanoi summit, North Korea has begun ratcheting up the pressure on South Korea again. Pyongyang has fired numerous short-range ballistic missiles and has threatened to restart nuclear tests and to take other actions unless the United States gives up what the Kim regime deems its hostile policy toward North Korea.

It remains to be seen how these on-again, off-again nuclear talks have affected and will continue to affect military readiness, but two points need to be considered. First, as long as the U.S. political leadership argues that a nuclear breakthrough is possible, the assertion that the most serious military threat to South Korea (and the United States) will decline is going to gain greater traction. If that remains the case, then all the ongoing steps that go into maintaining the highest possible degree of readiness could be affected.

Second, to maximize momentum for reaching a nuclear agreement with North Korea, South Korean policymakers or political leaders could argue that Pyongyang must be given more incentives, such as the further cancelation of U.S.-ROK military exercises. Indeed, Seoul Mayor Park Won-soon, an aspiring future presidential candidate in the ruling Democratic Party, gave a speech to that effect at the Council on Foreign Relations in January 2020. He said that the United States and South Korea should halt all military exercises until the end of the 2022 Beijing Winter Olympics to pave the way for North and South Korea to jointly host an Olympic Games in the future.7

With the outlook for diplomacy uncertain at best, South Korea has limited options for coping with the nuclear threat posed by North Korea. Seoul cannot help but continue to rely on the U.S. nuclear umbrella and its guarantee of extended deterrence. Even though the Trump administration continues to pressure Seoul to pay a larger share of the cost of stationing U.S. troops in South Korea by several magnitudes, Seoul has little choice but to continue to depend on a robust ROK-U.S. alliance to effectively deter North Korea.

A complementary step is to seek to counter North Korea’s nuclear warheads and other weapons of mass destruction in three ways: preemptive surgical strikes on North Korea’s strategic targets, bolstering the South Korean air and missile defense system, and putting into place counterstrike capabilities that would enable South Korea to hit all major targets from where North Korean attacks originate. As North Korea continues to develop and upgrade a wide range of ballistic missiles, there is little doubt that South Korea needs to augment its missile defense and retaliatory capabilities. But under the Moon government, the South Korean Ministry of National Defense has instead prioritized enacting CBMs with North Korea.

How Confidence Building Is Affecting Military Readiness and Interoperability

Though diplomacy with North Korea is all but stalled, the ROK has insisted that CBMs between the two Koreas have resulted in notable benefits such as the removal of guard posts inside the Demilitarized Zone. However, North Korea has not changed its order of battle nor the training regimen of the Korean People’s Army.

Nevertheless, the Moon administration hailed Seoul and Pyongyang’s September 2018 addendum to the Panmunjeom Declaration as a major accomplishment. Seoul argued that the September 2018 CBM agreement fostered a real reduction in military tensions between the two Koreas. Through the accord, the two Koreas agreed to “completely cease all hostile acts against each other,” and the two sides agreed to consult each other on a handful of important topics, including large-scale military exercises, blockades and interdiction, and reconnaissance.8

Among other things, Pyongyang and Seoul further committed to ceasing military exercises along the MDL between the two countries starting on November 1, 2018. In practice, this meant a halt to all ground forces’ regiment-level “live-fire artillery drills and field training exercises” within five kilometers of the MDL.9 The agreement also froze all live-fire naval drills and maritime maneuver exercises within a designated zone, as well as tactical live-fire drills involving fixed-wing aircraft, including the firing of air-to-ground guided weapons along parts of the MDL.10

While there is nothing wrong with CBMs in principle, it remains to be seen if North Korea will keep abiding by the September 2018 agreement. After all, Pyongyang has contravened previously agreed-to CBMs including provisions of the 1953 Korean War Armistice Agreement. North Korea temporarily suspended rocket launches and missile tests after the Singapore summit. But Kim resumed launching rockets and missiles around the East Sea from May to October 2019 and began testing new capabilities including a missile similar in build to the Russian Iskandar missile. Pyongyang also criticized combined U.S.-ROK exercises in August 2019 by publicly attributing all the causes of hostility to Washington and Seoul.11 To put the current focus on confidence building in perspective, the two Koreas signed a number of military CBMs as part of the 1990 Basic Agreement, but North Korea has not abided by them, as illustrated by Pyongyang’s numerous military provocations and limited attacks since then, such as the sinking of a South Korean naval vessel and the bombing of Yeonpyeong Island in 2010.

North Korea’s questionable willingness to abide by the CBMs is not the only drawback to the September 2018 agreement. Ceasing military exercises (including weapons firing), establishing a peace zone around the West Sea, and constructing inter-Korean roadways, for example, all look like promising ways to ease tensions near the MDL. But based on the superficial concessions North Korea has made on its largely unchanged offensive force posture, the CBMs are likely to weaken, rather than strengthen, South Korea’s defense posture. This is because most of North Korea’s artillery, tanks, and ground forces continue to be deployed along the thirty-eighth parallel close to Seoul and only 50 kilometers from the border. Whatever side benefits might arise from the September 2018 agreement on CBMs, North Korea has not substantively changed its military posture.

The Fate of Combined Military Exercises

It was no surprise that Pyongyang condemned ROK-U.S. combined military exercises as drills designed to invade North Korea. But no one expected a U.S. president to denounce the exercises with a longtime ally—nothing like that had been done before. Yet that is exactly what Trump said throughout the 2016 presidential campaign and has repeated since he was inaugurated, namely that the ROK-U.S. exercises are overly expensive and too hostile.12 By constantly attacking the combined exercises, Trump has frayed the fabric of deterrence. For its part, the Moon administration has not stepped in to defend the exercises, instead remaining silent on the issue for two key reasons. First, Seoul did not wish to anger Trump given the importance Moon has attached to sustaining inter-Korean and U.S.–North Korea détente. Second, implicitly endorsing Trump’s position on canceling exercises added momentum to Moon’s own push for inter-Korean engagement.

With few champions in their corner, the exercises were drastically rolled back. In August 2018,13 Seoul and Washington agreed to suspend the annual Ulchi Freedom Guardian exercise and to review additional measures to ease military tensions.14 The decision to halt this exercise came more than forty years after it was initiated in 1976 under the name Ulchi Focus Lens. It had been renamed Ulchi Freedom Guardian in 2008. Less than a year after that drill was suspended, in March 2019, the two countries decided to also downsize the annual, large-scale Key Resolve and Foal Eagle military exercises in the spring, so as to avoid provoking North Korea.15 Instead, the allies carried out the Dongmaeng exercise, an alliance command post exercise, in March 2019 as a replacement for the two exercises. But whether this reformatted approach can replace actual exercises is highly debatable.

Furthermore, South Korea announced that it was planning to launch a new civilian-military exercise named Ulchi Taegeuk in late May 2019 to help replace the ROK-U.S. Ulchi Freedom Guardian exercise.16 It effectively combined the ROK’s independent Taegeuk command post exercise in May and the Ulchi government exercise in August. The new exercise focuses on strengthening South Korea’s independent abilities to fend off armed attacks and to respond to terrorist attacks and natural disasters. Though the two governments are planning to launch a downsized exercise instead, all major, large-scale ROK-U.S. combined exercises, for now, have ended.

The Fallout of Canceled Exercises

A crucial facilitator of U.S.-ROK interoperability is the Combined Forces Command (CFC). CFC uses a combined U.S.-ROK command structure that was formed in 1978 to enhance interoperability between the two forces in response to president Jimmy Carter’s initial plan to gradually withdraw U.S. ground forces from South Korea, a plan that was never put into practice due to new intelligence assessments on North Korean forces. As for the current exercises for theater-level command and control, they usually take the form of a command post exercise supported by computer-aided war games.17 A red team acting as North Korean forces fights against a ROK-U.S. CFC Forces team on a computer-generated battlefield. At the command post, the CFC commander and relevant staff evaluate the computer-generated battlefield situation based on the report from the ROK-U.S. CFC Forces, make decisions based on standard operating procedures, and issue corresponding operational orders.

The side effects of the recent cancelations and downgrades on readiness and interoperability are noteworthy. Reducing training and exercises predictably degrades military preparedness. The cancelation of exercises is likely to have minimal impact on Korea-wide and theater-level command and control. While U.S. and ROK forces have routinely undertaken command post exercises, previously these exercises were held to complement actual military exercises involving the two forces and not to, in effect, replace them. Even though simulations can be realistic, they can never fully replace actual military training and exercises.

At the tactical level, however, the impact of the changes to combined exercises and training are likely to be quite negative. For all branches of the two countries’ militaries, any significant reduction in combined training means that ROK and U.S. forces will have far fewer assurances about their interoperability under actual combat conditions. If combined training and exercises are halted for a prolonged period, it will be difficult to restore the level of interoperability needed to respond effectively to possible North Korean provocations. This is significant because the interplay between readiness and interoperability is critical on the Korean Peninsula, given the combined command structure. In a contingency, U.S. forces and ROK forces at every level would have to be familiar with how to integrate their responses effectively, a function receiving less attention with downsized exercises.

It may be politically desirable to send a positive signal to North Korea by reducing or canceling major U.S.-ROK combined training and exercises, but there is no denying that interoperability and readiness are going to suffer. This is because the Moon government continues to argue that the military situation on the Korean Peninsula is improving, that the North Korean threat is receding and, hence, that there is a reduced need for more robust exercises between the two forces. Moreover, Trump’s incessant criticism of exercises coupled with his opposition to sending select strategic assets such as bombers, F-22 fighters, and aircraft carriers to the Korean Peninsula, has already caused significant strategic damage to the alliance and readiness. Trump’s posture has weakened the allies’ ability to deter North Korea and has sent Pyongyang conflicting signals at a time when Seoul and Washington have to speak more cohesively.

Responding to North Korea’s increasingly potent nuclear arsenal also has become more difficult due to the downturn in South Korea–Japan relations. When Japan initially removed South Korea from its white list, Seoul threatened to terminate an important intelligence-sharing mechanism with Tokyo that Washington strongly encouraged and championed. The General Security of Military Information Agreement allowed South Korea and Japan to share important information on North Korea’s nuclear program, and ending the mechanism would have dealt a severe blow to efforts to contain the threat posed by Pyongyang and to deepen three-way security cooperation between Seoul, Tokyo, and Washington.

While the Moon government ultimately decided not to terminate the agreement for now, this issue still has key implications for readiness and interoperability. This is because stable intelligence sharing with Japan enhances security cooperation and coordination in the context of trilateral ties between the United States, South Korea, and Japan. Since Japan is critical in the context of United Nations Command–Rear (UNC–Rear) support, assuring unfettered Korean-Japanese intelligence sharing complements existing security mechanisms.

How Operational Control and Cost Sharing Affect Readiness

The readiness and interoperability of ROK-U.S. forces is not just affected by routine logistical considerations such as when and how to hold exercises; rather, these dimensions of alliance effectiveness are also shaped by factors more foundational to the alliance itself. For example, two critically related issues for the ROK-U.S. alliance are the question of who would issue orders to combined forces in combat situations and how the fiscal burden of defense costs should be shared.

Transferring Operational Control

The ROK and the United States have been discussing the transfer of the wartime operational control (OPCON) of ROK forces from U.S. military commanders back to South Korean military officers for some time. This very complicated process is related closely to readiness, military capabilities, and the future status of U.S. forces on the Korean Peninsula. For the purposes of historical context, it is important to know that OPCON of South Korean forces was transferred to the commander of the United Nations Command, a U.S. general, at the outbreak of the Korean War. While there always has been a dual national command authority, in operational terms, this meant that the head of the U.S. forces in South Korea also exercised OPCON during peace and wartime.

In light of South Korea’s rapid economic development and the political importance of OPCON, peacetime OPCON was transferred back to the ROK in the early 1990s. Successive ROK governments then turned their attention to transferring wartime control back to the ROK, but the main factor with respect to timing was whether the South Korean forces had the requisite strategic and tactical capabilities to retain full OPCON. The Moon government has called for the expedited reversion of wartime OPCON provided that those conditions are met.

In late October 2018, then U.S. secretary of defense Jim Mattis and ROK Minister of National Defense Jeong Kyeong-doo unveiled a joint communique that spurred progress on the transfer of OPCON after the fiftieth ROK-U.S. Security Consultative Meeting held in Washington, DC.18 The joint communique reported that both sides acknowledged progress on essential conditions for a successful transfer, as previously agreed to in June 2017, such as heightened ROK military capabilities and the drafting of certain strategic documents. For his part, Jeong attributed the significant progress made toward conditions-based transfer of OPCON to the Moon administration’s Defense Reform 2.0.19 Meanwhile, Mattis confirmed that the United States would stay committed to providing necessary bridging capabilities until South Korea was fully ready to assume an independent self-defense.20

Notably, there are sound operational reasons for transferring OPCON. Most importantly, as the world’s twelfth-largest economy and a major Asian power, South Korea understandably sees it as simply a matter of sovereignty for it to have control over its own military forces. Notwithstanding the centrality of the ROK-U.S. alliance to the country’s national security, it also makes sense for the ROK to retain full OPCON so as to bolster its overarching warfighting capabilities. South Korea’s advanced defense industrial base also means that it is increasingly capable of developing and deploying indigenous platforms.

That said, given South Korea’s ongoing dependence on the United States for critical strategic intelligence and other key military assets, there are those who worry that if wartime OPCON is transferred back to the ROK, the United States will have less of an incentive to help defend South Korea. Moreover, once the ROK receives full OPCON and tangible progress (however unlikely) is made on the North Korean nuclear threat, the rationale for maintaining the 28,500-strong United States Forces Korea (USFK) could be weakened.21

Purely on the merits of military effectiveness, a transfer of OPCON would likely be manageable if the two militaries coordinate properly. The current CFC command structure could accommodate any four-star general, regardless of nationality, to exercise the command authority. The commander is staffed and supported by professionally educated and highly experienced combined battle staffs and component commanders, who oversee their respective predesignated areas of operations (land, sea, and air). Technically speaking, the nationality of the CFC commander need not be a major issue.

For example, the Ground Component Command, which is responsible for all relevant ground operations, is already under the command of a four-star ROK Army general who also serves as deputy commander of CFC. The Ground Component Command has been organized into the Ground Operations Command in peacetime as well as wartime since 2019. This is significant because it illustrates the ROK’s ability to assume a leading role in ground operations. If another war breaks out, the ROK Army is going to assume the lion’s share of ground operations, although USFK and augmented U.S. forces would be central to conducting combined ground-air counterattacks.

Nonetheless, transferring OPCON would likely have more negative political and diplomatic consequences. Because the number of service members in USFK units is not equivalent to the unit of a four-star general, the rank of the U.S. commander could be downgraded to a three-star general after the transfer of OPCON. One of the reasons that the USFK commander traditionally has been a four-star general is that the commander leads CFC. If the USFK commander does not serve as commander of CFC, the rank could be downgraded to a three-star general, who would presumably have less clout in the Pentagon than a four-star general. A three-star U.S. general in a reconfigured CFC would also have less influence with the ROK Ministry of National Defense and armed forces.

Far more important than the operational dimensions of transferring OPCON is the degree of trust that will continue to exist between the two countries’ armed forces. The ROK should rightly take the lead on its own defense and transferring OPCON is a necessary step in this direction. But ensuring seamless interoperability at all levels of operation after such a transfer is the central task that the highest political and military leaders in South Korea and the United States need to manage.

Once wartime OPCON reverts to Seoul, both the ROK and the United States will have to ensure that interoperability throughout the chain of command remains unbroken and highly effective. How the two sides perceive North Korean provocations and appropriate military responses could differ under a new command arrangement, although South Korea’s perceptions of these issues also depend on the type of government that is in power in Seoul. How the allies maintain unity of effort after a full transfer of OPCON is both a highly political and a definitively military task.

Cost Sharing

Cost sharing has also been a contentious issue between the ROK and the United States. In the past, Seoul and Washington typically signed special measures agreements to define how costs would be split for five years at a time, but the latest agreement (signed in February 2019) was valid for just one year (2019).22 Under the 2019 agreement, South Korea is paying the United States about $920 million, an increase of 8.2 percent compared to the previous year.23 Admittedly the size of this increase is not unusually high compared to those in previous years. But the key is whether the United States will continue to insist, as Trump has, that the ROK should pay exponentially more for the cost of stationing U.S. troops in South Korea.24

Tensions remain high as South Korea and the United States negotiate a new agreement on how these costs should be divided in 2020. Trump has insisted that South Korea’s annual contribution should rise from roughly $920 million in 2019 to $5 billion for 2020 to cover the costs of defending South Korea and the region, pointing out that the ROK benefits from this arrangement. Seoul has balked at this demand that it should pay significantly more. For whatever reason, Trump believes that South Korea (and other U.S. allies like Japan) have been essentially free riders when it comes to cost sharing on defense expenditures.25

But the sticker price of the 2019 agreement does not fully capture how much Seoul has spent on national defense and the alliance. Aside from South Korea’s annual direct contribution of about $920 million in 2019, Seoul also has foregone an estimated $1.5 billion to $4 billion (according to the Wall Street Journal) in annual rent payments by providing U.S. troops with rent-free facilities in the Yongsan district of Seoul.26 And though the vast majority of U.S. forces vacated those facilities at the end of 2019, South Korea also absorbed most of the costs of building the new U.S. base at Camp Humphreys in Pyeongtaek to which they were relocated, a base that cost about $10.8 billion. In the grand scheme of things, then, Seoul is hardly free riding. It remains to be seen how the negotiations on cost-sharing will ultimately conclude. Either way, the negotiations on cost-sharing take their toll on the alliance by consuming energy and political will that could otherwise be directed toward bolstering readiness and interoperability.

South Korea’s Defense Reforms

Amid a hostile security environment and a host of other hurdles to maintaining readiness and preserving interoperability, the South Korean government has undertaken extensive military reforms. In late July 2018, a little over a year after the Moon government took office, the Ministry of National Defense announced the measures billed as Defense Reform 2.0.27 According to the government’s official announcement, the total cost of the reforms will run 270.7 trillion won (about $230 billion) from 2019 to 2023 (see table 2).28 In August 2019, the ministry released the midterm defense program plan for 2020–2024, which contains key defense spending programs for the five-year period.29 

Table 2: Moon’s Defense Budget
    2017 2018 2019 2020 2021 2022 2023
  Total (in billions) $34.3 $36.7 $39.7 $42.8 $46.0 $49.1 $52.5
  Annual growth rate 4.0% 7.0% 8.2% 7.8% 7.5% 6.8% 7.0%
Force operating budget % of total budget 69.7% 69.3% 67.8% 67% 66.2% 65.3% 64.3%
Force enhancement budget % of total budget 30.6% 31.9% 33.4% 34.2% 35.0% 35.9% 36.8%
Source: ROK Ministry of National Defense, 2018 Defense White Paper

Note: Some of the budget percentages add up to slightly more than 100 percent, due to rounding. The budget amounts are calculated in U.S. dollars at an exchange rate of $1 to 1,169 Korean won. The force enhancement budget includes line items such as R&D and acquisitions.

One major component of the reforms is a sizable reduction of the South Korean military. Part of the strategy is to shrink the force structure from approximately 599,000 to 500,000 active duty personnel over the next few years.30 A key concern is that the total length of mandatory military service in the army is also expected to be cut from twenty-one months to eighteen months by 2022.31 On that front, some observers question whether the ROK military’s combat readiness may suffer on account of more rapid turnover in conscripted forces.

The reforms will also alter the command structure and the missions of various military branches in important ways. There is a plan to appoint a new ROK four-star general to the position of the chairman of the Joint Chiefs of Staff, who will serve as commander of CFC after wartime OPCON is eventually transferred.32 Changes are also slated for specific branches. For instance, the newly formed Ground Operations Command is in charge of a wide range of missions, including defending the Seoul metropolitan area from North Korea’s long-range artillery located along the MDL.

While Moon’s Defense Reform 2.0 aims to improve the ground forces in various ways, much of the emphasis has been placed on upgrading the country’s naval and air capabilities. This preoccupation signals the Moon administration’s focus on asymmetrical threats from North Korea and newly emerging regional threats. As part of a unit realignment, the ROK Air Force headquarters plans to establish a new reconnaissance wing for improved long-distance and space operations. The navy will enlarge its maritime task flotilla and aviation wing to further develop capabilities for surface, underwater, and aerial operations.

To support these mission changes, the South Korean government has allocated budget outlays for procuring key weapons systems between 2020 and 2024. To enhance South Korea’s intelligence capabilities, compensate for the retirement of the U-2 reconnaissance aircraft, and improve the country’s ability to track and target weapons of mass destruction, the South Korean military plans to purchase high-altitude reconnaissance unmanned aerial vehicles. Specifically, it will likely buy Global Hawk surveillance aircraft, which can cover almost all of North Korea without crossing the MDL.33

Other procurement upgrades are also on the horizon. The ROK Air Force is going to purchase additional fifth-generation fighters such as the F-35 Joint Strike Fighter.34 Due to its stealth capability, F-35 aircraft assume a significant role in countering weapons of mass destruction, and they would be particularly instrumental in executing preemptive attacks in case of a potential nuclear attack by North Korea, although such a move would be heavily influenced by who will sit in the Blue House and other key political considerations. In addition, the ROK Navy will build new Aegis-class destroyers and a large cargo ship that could be modified into a light aircraft carrier. To conduct aerial operations with an aircraft carrier, the navy also deems it necessary to purchase a certain number of F-35 B fighters, which have vertical take-off and landing capabilities.35 

Critics of the Moon government’s defense reform plans have argued that while the ROK needs to replace aging platforms such as the nearly defunct F-4 and F-5 fighters, and while the navy has to strengthen its submarine forces, buying more high-tech weapons systems does not necessarily mean that the ROK’s overall combat capabilities will also increase. The outcome of these reforms will ultimately depend on how well the Ministry of National Defense can forge consistent policies in the remaining years of the Moon government. Another relevant consideration is how much of this reform program will be sustained by the succeeding administration that will come to power in May 2022. Moreover, the result of cost-sharing negotiations with the United States, the status of transferring OPCON, and steps the Trump administration could take related to USFK will also affect the outcome of these ambitious defense reform plans.


Since Moon took office, his administration has primarily emphasized CBMs with North Korea including three inter-Korean summits and the signing of a major military agreement in September 2018. Nevertheless, North Korea’s nuclear arsenal has continued to grow, not to mention the country’s stockpile of advanced ballistic missiles including submarine-launched ballistic missiles. Since the failure of the 2019 Hanoi summit, there has been no progress on denuclearization. It is still not impossible that Washington and Pyongyang could reach an agreement in 2020 before the U.S. presidential election, but chances of that happening are quite slim.

Readiness depends on political and psychological factors as much as it does on interoperability, critical military capabilities, and combinedness between ROK and U.S. forces.

Most military experts agree that the process of implementing provisions of the September 2018 agreement on confidence building is moving much faster than denuclearization. Indeed, despite no change in the North Korea military’s order of battle or key deployments—not to mention its exercises and force upgrades such as longer-range multiple rocket launchers—the ROK has had to slim down or cancel exercises with the United States to provide incentives for ongoing nuclear talks. Meanwhile, the Moon government wants to expedite a transfer of wartime OPCON in the belief that such a move would strengthen its stance toward North Korea. After several North Korean short-range rocket and missile tests in the fall of 2019, the ROK government basically opted not to respond since Seoul did not want to rock the boat with Pyongyang.

In the end, readiness depends on political and psychological factors as much as it does on interoperability, critical military capabilities, and combinedness between ROK and U.S. forces. If political leaders in Seoul continue to insist that the overarching military threat from North Korea is abating when it is not and that Kim is going to denuclearize when he has no intention of doing so, accurate threat assessments will be even more highly politicized and the ROK’s core defense policy stances will be improperly tailored to match political considerations. In the end, such moves cannot help but negatively affect South Korea’s defense readiness at a critical moment in inter-Korean relations and a shifting balance of power in Northeast Asia.

About the Author

Shin Beomchul is a former senior fellow at the Asan Institute for Policy Studies. He is an expert on Korean security, North Korea’s military strategy, and the ROK-U.S. alliance. He has served in key government posts including the Office of the Minister of National Defense and as the director general for policymaking at the Ministry of Foreign Affairs.


1 South Korean Ministry of Foreign Affairs, “Panmunjeom Declaration for Peace, Prosperity and Unification of the Korean Peninsula.” April 27, 2018,

2 Ibid.

3 Ibid

4 Ibid.

5 Edward Wong, “Trump’s Talks With Kim Jong-un Collapse, and Both Sides Point Fingers,” New York Times, February 28, 2019,

6 Ibid.

7 Ibid.

8 The National Committee on North Korea, “Agreement on the Implementation of the Historic Panmunjom Declaration in the Military Domain,” September 19, 2018,

9 Ibid.

10 Ibid.

11 Kim Tong-hyung, “North Korea Fires Presumed Ballistic Missiles, Denounces US-South Korea Military Drills,” Military Times, August 5, 2019,

12 Lee Min-hyung, “S. Korea, US Suspend Annual Military Drills,” Korea Times, September 5, 2018,

13 Ibid.

14 Lee Min-hyung, “Korea and US Axe Two Annual, Large-Scale Joint Military Drills,” Korea Times, March 11, 2019,

15 Dan Lamothe, “U.S. and South Korea End Military Exercises That Riled North Korea in Favor of Something Smaller,” Washington Post, March 3, 2019,

16 Ibid.

17 Christy Lee, “Experts: US-South Korea Pare Military Exercises as North Korea Remains Threat,” Voice of America, August 8, 2019,

18 USFK, “Joint Communiqué of 50th U.S.-ROK Security Consultative Meeting,” October 31, 2018,

19 Ibid.

20 Ibid.

21 Andrew Jeong, “To Make Korea Pay More for Security, Trump Has to Show His Shopping List,” Wall Street Journal, January 7, 2020,

22 South Korean Ministry of Foreign Affairs, “ROK and US Reach Agreement on 10th Special Measures Agreement,” February 10, 2019,

23 Lee Min-hyung, “Trump Wants Seoul to Pay More for US Troops,” Korea Times, February 20, 2019,; and Simon Denyer and Min Joo Kim, “United States and South Korea Reach Stopgap Deal on Troop Cost-Sharing,” Washington Post, February 10, 2019,

24 Ibid.

25 Ibid.

26 See, for example, Jonathan Cheng and Choe Yun-hwan, “Despite Complaints, U.S. Gets a Key Benefit in South Korea: Free Rent,” Wall Street Journal, May 13, 2018,

27 Song Sang-ho, “Defense Reform Plan to Cut Generals, Create Ground Command, Retain 3-Axis System,” Yonhap News Agency, July 27, 2018,

28 Ibid.

29 Jung Da-min, “Seoul to Budget Over 50 Trillion Won for Defense to Counter Growing Security Threats,” Korea Times, August 13, 2019,

30 South Korean Ministry of National Defense, 2018 Defense White Paper, 118,

31 Yeo Jun-suk, “S. Korea Military Seeks to Cut Service Period to 18 Months,” Korea Herald, May 3, 2018,

32 Jung, “Seoul to Budget Over 50 Trillion Won for Defense to Counter Growing Security Threats.”

33 Ibid.

34 Ibid.

35 Ibid.