[Global NK Commentary] Modernizing the ROK-U.S. Alliance: Alliance Vision and Key Areas

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The ROK-U.S. alliance is at a critical inflection point due to the changed security environment, shifts in U.S. alliance strategy, and the growth of South Korea's national power. Depending on how the alliance's vision is set and how the roles and responsibilities of the ROK and U.S. militaries are developed to realize that vision, the alliance can gain momentum and achieve greater things.

The ROK and U.S. have begun consultations to strengthen the alliance's capabilities and posture based on a shared understanding of the alliance's future direction amidst a changing regional security environment. Both sides are consulting on modernizing the ROK-U.S. alliance with the goal of rebalancing roles and responsibilities between the U.S. and ROK forces on the Korean Peninsula while maintaining extended deterrence.[1]

The ROK-U.S. military alliance was born out of the Mutual Defense Treaty between the Republic of Korea and the United States, signed on October 1, 1953. Over the past 70 years, the ROK-U.S. alliance has played a crucial role in maintaining peace through deterrence on the Korean Peninsula, contributing to the development of South Korea's liberal democracy and its growth into a top 10 economic power. The ROK-U.S. alliance, which is evolving from a Supported-Asymmetric Alliance to a Reciprocal-Symmetric Alliance, needs to be newly readjusted to effectively cope with the changing security strategic environment.

With this strategic understanding, this article aims to provide a comprehensive strategic assessment of the security environment. Subsequently, it will discuss the current state and future directions of six key areas for the modernization of the ROK-U.S. alliance: the alliance's vision, expansion of alliance roles, strategic flexibility of U.S. Forces Korea, transfer of ROK-U.S. wartime operational control, the North Korean nuclear challenge, and defense and national defense budget increases.

I. Comprehensive Strategic Assessment of the Security Environment

The ROK-U.S. alliance originated from the fierce battles of the Korean War, undertaken as part of the Soviet Union's "Eastern Bypass Global Strategy" to block the spread of communism. The ROK-U.S. alliance participated in the Vietnam War, confronting new forms of military threats such as North Korea's localized provocations and terrorism. The Cold War ended with the collapse of the Soviet Union and the dissolution of Eastern European countries. Although a U.S.-led liberal order seemed to be established, the international war on terror, including the Afghanistan and Iraq Wars, continued following the September 11, 2001 terrorist attacks. After navigating the 2008 global financial crisis, China's surpassing Japan's GDP in 2010 marked the full-fledged entry into an era of U.S.-China hegemonic competition.

As domestic political realignments intersect with international political conflicts, armed conflicts are occurring in various parts of the international community, and geopolitical tensions and conflicts are intensifying.

The series of events from the state of emergency martial law on December 3, 2024, to the presidential election on June 3, 2025, were a triumph for South Korean democracy. South Korea's internal conflicts between progressives and conservatives, and regional, generational, gender, and class divisions, also pose challenges from a security perspective. The progressive and conservative governments have pursued chaotic North Korea and unification policies. South Korea, which holds an overwhelming advantage in all fields compared to North Korea, is being manipulated by North Korea in the military domain.

North Korea's foreign policy strategy involves pursuing an adversarial stance towards South Korea and the U.S. while maintaining a strategy of regime survival and balancing diplomacy with China and Russia.[2]The North Korean military is highly likely to attempt a surprise attack focused on asymmetric capabilities during a contingency to create favorable conditions and conclude the war early. North Korea appears to be strategically employing a new Cold War. North Korea and Russia signed the Treaty on the Comprehensive Strategic Partnership on June 18, 2024. North Korea's deployment of 11,000 combat troops to the Russia-Ukraine war to gain experience in modern warfare, and potential support for military satellites, ICBM re-entry technology, and nuclear-powered submarine construction, along with guarantees of Russian military intervention, pose a threat to the ROK-U.S. alliance. Kim Jong Un has defined inter-Korean relations not as fellow countrymen but as belligerent adversarial states,[3]and is encouraging a great catastrophe as an object of annihilation. It is assessed that North Korea currently possesses approximately 50 nuclear warheads and fissile material capable of producing about 90 more.[4]With an estimated possession of around 180 nuclear weapons and 10 ICBMs by 2027, it is assessed that they will threaten not only the Korean Peninsula but also the U.S. mainland.[5]North Korea enacted the Law on the Rejection of Anti-Socialist Ideology and Culture in 2020, the Law on Guaranteeing Youth Education in 2021, and the Law on Protecting the Pyongyang Dialect in 2023, further tightening control over its citizens. The regime faces challenges to its stability due to worsening economic pressure.

The resurgence of Trump, campaigning under the banner of "Make America Great Again (MAGA)," is causing global economic and security order to fluctuate. Xi Jinping's long-term rule, emphasizing "Socialism with Chinese Characteristics for a New Era" and "Chinese Modernization," openly pursues an Anti-Access & Area Denial (A2&AD) strategy to seize maritime hegemony, while engaging in full-scale military demonstrations for the potential occupation of Taiwan. Through the Belt & Road Initiative (BRI), China is constructing a world order centered on maritime, land, and digital domains. It is expanding its sphere of influence by strengthening solidarity among Global South countries and cooperation through regional organizations and BRICS.[6]The economies of China and Europe are slowing down, and a reorganization of global supply chains and trade wars are underway. The advent of new industrial revolutions, including AI technology development and AI-driven new industries, is occurring. Global warming is causing seismic shifts on Earth, posing a threat to humanity.

In the era of the New Cold War, with convergent geopolitics, the geopolitical center of gravity is shifting from Europe to Asia. Key actors are evolving from great powers to a convergence of great and middle powers. Alliance dynamics are shifting from bilateral alliances to multilateral security, and the connectivity between Asian and European security is strengthening.[7]

The ROK-U.S. alliance needs to redefine its vision and readjust the roles and responsibilities of the U.S. and ROK militaries to build a peaceful and stable world and address new complex security challenges by sharing threat perceptions.

II. Key Issues for Modernizing the ROK-U.S. Alliance

1. Alliance Vision

1) Contributions of the ROK-U.S. Alliance

Reflecting on the past 70-plus years of the ROK-U.S. alliance, this section aims to evaluate its contributions and examine the vision and strategic direction for its renewal.

The ROK-U.S. alliance, born from the fierce battles of the Korean War, was institutionalized with the signing of the Mutual Defense Treaty on October 1, 1953. During the Korean War, the number of casualties among South Koreans who sacrificed to reclaim their territory and defend liberal democracy reached 1,612,477 (137,899 military deaths/missing, 373,599 civilian deaths/missing, 450,741 military wounded, 680,367 civilian wounded, 32,838 military POWs/missing, 303,212 abducted civilians, 84,532 missing civilians), and U.S. casualties reached 129,514 (33,643 deaths, 92,134 casualties, 3,737 POWs).[8]Over 4.85 million U.S. military personnel (2.83 million Army, 1.6 million Navy, 420,000 Air Force) participated.[9]The Korean War had ended.

The United States provided $139.76 million in aid to South Korea, which was reduced to ashes by the Korean War, until 1999.[10]South Korea, once one of the poorest countries, was able to develop economically through technology transfer, imports of Korean goods, and the transfer of know-how for economic development, becoming the only country to transition from receiving aid after World War II to providing it. The U.S. facilitated the study of advanced academics and science and technology for Korean youth through programs like the Fulbright Scholarship, enabling them to return and contribute to national development. The economic value of the ROK-U.S. alliance is estimated to be twice South Korea's annual defense budget due to the cost savings in defense spending resulting from the presence of U.S. forces.[11]Through direct and indirect intervention policies, the U.S. checked authoritarian regimes and contributed to the establishment of freedom of the press, human rights, and the rule of law in South Korean society.

The ROK-U.S. alliance has performed its deterrence function through the U.S. Forces Korea, the Combined Forces Command, and ROK-U.S. consultative bodies. The stationing of U.S. Forces Korea has contributed to deterrence by ensuring U.S. intervention, as the U.S. would consider any armed invasion by North Korea as a war against the United States. The ROK-U.S. Combined Forces Command has developed operational plans for wartime contingencies and has contributed to deterrence by demonstrating the capability to deploy U.S. reinforcement forces to the Korean Peninsula through various ROK-U.S. combined exercises. Furthermore, as ROK-U.S. consultative bodies, the annual Security Consultative Meeting (SCM) between the ROK and U.S. Ministers of National Defense and the Military Committee Meeting (MCM) between the Joint Chiefs of Staff of both countries have contributed to deterring war on the Korean Peninsula through security assessments and threat management.[12]

On the other hand, the ROK-U.S. alliance, within the U.S.-led combined defense system, has led to an excessive security dependence on the alliance and has had dysfunctional effects such as causing identity confusion for the ROK military and limiting its autonomy in military operations.

2) Vision and Strategic Direction of the ROK-U.S. Alliance

The vision for the ROK-U.S. alliance is the denuclearization of the Korean Peninsula, the establishment of a peace regime, the institutionalization of security cooperation in Northeast Asia, and the construction of a global liberal international order.

The strategic principles of the alliance are as follows: First, the ROK-U.S. alliance upholds core values of freedom, democracy, the rule of law, market economy, and human dignity. Second, it guarantees strategic autonomy to enable continuous growth and development through innovation and creativity. Third, the ROK-U.S. alliance pursues a principle of reciprocity. Fourth, as an alliance, both the ROK and U.S. fulfill their responsibilities with a sense of mission for the roles they are obligated to perform.

The future vision of the ROK-U.S. alliance, presented concretely at the Korean Peninsula, Northeast Asia, and global levels, is as follows: At the Korean Peninsula level, it is the denuclearization and establishment of a peace regime. On April 23, 2023, on the occasion of the 70th anniversary of the ROK-U.S. alliance, the ROK-U.S. summit statement declared, "The two allies will work to create a better future for all members of the Korean Peninsula and support a free and peaceful unified Korean Peninsula."[13]The mission of the ROK-U.S. alliance is to realize a unified Korea based on freedom. The emergence of a unified Korea would signify the end of the Cold War system in a civilizational context. It would not only liberate 26 million North Korean compatriots suffering from poverty and human rights abuses but also convey a message of hope to nations that have failed due to internal conflict and dictatorship. It would serve as an opportunity to foster a global civilization community that integrates Eastern and Western civilizations. It is proposed to establish a Presidential Committee for ROK-U.S. Korean Unification Consultative Committee. This committee would develop the vision for a unified Korea and formulate policies by developing strategies for its realization.

At the Northeast Asian level, it will engage in activities to build trust through mutual exchange and cooperation with regional countries and jointly exercise leadership in transforming the order of conflict and confrontation in Northeast Asia into an order of cooperation and coexistence. An institutional framework for security cooperation in Northeast Asia involving South Korea, North Korea, the U.S., Japan, China, Russia, and Mongolia will be established. A Northeast Asian Rapid Response Force, composed of military personnel, medical teams, police, and NGOs, will be created to jointly respond to regional disasters and natural calamities, enabling rapid deployment to conduct Humanitarian Assistance & Disaster Relief (HA&DR) operations.[14]

At the global level, the ROK-U.S. alliance will uphold peacekeeping operations, non-proliferation of weapons of mass destruction, anti-piracy operations, protection of maritime routes, cyber warfare, and the liberal international order.

2. Expanding the Role of the ROK-U.S. Alliance

The preamble of the Mutual Defense Treaty between the Republic of Korea and the United States states, "Each Party recognizes that an armed attack in the Pacific Area on either of the Parties would be dangerous to its own peace and safety and declares that it would act to meet the common danger in accordance with its constitutional processes." Article 3 states, "Each Party recognizes that an armed attack in the Pacific Area on either of the Parties would be dangerous to its own peace and safety and declares that it would act to meet the common danger in accordance with its constitutional processes."[15]Based on this alliance spirit, if hostile forces launch an armed attack on an allied nation in the Pacific region and engage in armed conflict with U.S. forces, the participation of the allied nation, South Korea, is natural.

In accordance with the alliance spirit, South Korea participated in the Vietnam War from 1965 to 1973 with two combat divisions, totaling 325,517 personnel, with 5,099 deaths and 11,232 wounded, incurring casualties.[16]The deployment of the Zaytun Division to the Iraq War and the Osheno Unit to the Afghanistan War was also based on the spirit of alliance and the ROK-U.S. Mutual Defense Treaty.

If China invades Taiwan and the Chinese carrier strike group attempts to seize the First Island Chain, the Jeju Fleet Command[17] could deploy forces to intercept the Chinese military. When China invades Taiwan, the ROK Marine Corps, along with the U.S. Marine Expeditionary Force deployed to Okinawa, could participate in operations to prevent a Chinese landing.[18] This must be done within the scope that does not undermine the deterrence of war on the Korean Peninsula.

If a free allied nation sharing our values is invaded, we believe that based on the spirit of alliance, we should jointly respond to aggression, whether the challenging power is China or Russia. At the Camp David ROK-U.S.-Japan Summit on August 18, 2023, it was declared that we would "jointly respond to regional challenges, provocations, and threats."[19] The ROK-U.S.-Japan leaders agreed to establish the ROK-U.S.-Japan Cooperation Office in Seoul in November 2024 to implement the Camp David Accords.[20] We propose the operation of a ROK-U.S.-Japan Trilateral Military Cooperation Task Force composed of strategic planners and security experts from the ROK Joint Chiefs of Staff, U.S. Indo-Pacific Command, and the Japan Self-Defense Forces Operational Command. By simulating scenarios such as a war on the Korean Peninsula, a war over Taiwan, or simultaneous wars on the Korean Peninsula and Taiwan through wargames, the roles and responsibilities of the ROK, U.S., and Japan in each situation can be identified. Such activities will have the effect of deterring war and contribute to victory in military operations in case of contingency.

3. Strategic Flexibility of U.S. Forces Korea

Foreign Minister Ban Ki-moon and U.S. Secretary of State Condoleezza Rice agreed on January 23, 2006, during the ROK-U.S. Strategic Dialogue that "Korea, as an ally, fully understands the logic of the transformation of U.S. global military strategy and respects the necessity of strategic flexibility for U.S. Forces Korea."[21]

Traditionally, U.S. Forces Korea has focused on defensive missions to deter military threats from North Korea. However, in the current security environment, the Korean Peninsula and the Indo-Pacific region are organically linked, and major international issues such as the U.S.-China strategic competition have cascading effects. Consequently, the mission scope of U.S. Forces Korea is expected to expand significantly to encompass pan-regional missions, including participation in U.S.-led multi-domain operations in Taiwan, the South China Sea, and the East China Sea.[22]

This means that U.S. Forces Korea can be redeployed to other regions in the event of military conflict, not just to manage North Korean threats. Regarding the expanded role of U.S. Forces Korea, it is necessary to limit the outward flow (flow-out) of forces to other regions in case of armed conflict to once, and to redeploy them via U.S. military bases in Japan, thereby preventing the Korean Peninsula from being repeatedly used as a staging base.[23]

Similarly, when Patriot batteries were recently redeployed to the Middle East, fifth-generation F-35 fighter jets were deployed as rotational replacements.[24] It should be agreed with the U.S. side that forces from U.S. Forces Korea can be deployed as replacements either before or simultaneously with their deployment.

Meanwhile, a reduction or withdrawal of U.S. Forces Korea could be perceived as a weakening of security commitments, potentially inviting invasion by North Korea or China, and therefore, redeploying or withdrawing U.S. Forces Korea to Okinawa, Guam, or the Philippines is not advisable. U.S. forces stationed on the Korean Peninsula, the strategic center of Northeast Asia, play a crucial role in deterring not only North Korea but also China and Russia. The importance of U.S. Forces Korea has further increased amidst the intensifying U.S.-China power competition.

4. Transition of Wartime Operational Control (SOTM) between ROK and U.S.

The ROK and U.S. governments clearly intend to pursue the transition of wartime operational control. The Trump administration, through its Interim National Defense Strategic Guidance, stated, "The United States will focus on deterring China's invasion of Taiwan and defending the U.S. homeland, and will delegate most of the role of deterring North Korean threats to its allies."[25] The Lee Jae-myung administration also maintains a stance of pursuing the transition of operational control within its term.[26]

The military must prepare for the worst-case scenario. The possibility of Xi Jinping and Kim Jong-un colluding to initiate simultaneous wars in Taiwan and on the Korean Peninsula cannot be ruled out. In the event of simultaneous wars in two regions, U.S. experts state that the United States would commit not only its forces in Japan and Guam but also those of U.S. Forces Korea to the war over Taiwan, leaving South Korea to defend itself independently.[27]

The ROK and U.S. Ministers of Defense agreed on the Conditions-based Operational Control Transition Program (COTP) in 2014.[28] Condition 1: The ROK military secures the necessary military capabilities to lead combined defense. Condition 2: The alliance secures comprehensive capabilities to respond to North Korea's nuclear and missile threats. Condition 3: A stable security environment on the Korean Peninsula and in the region conducive to the transition of operational control.

The ROK and U.S. Ministers of Defense agreed on October 31, 2018, to launch the Future Combined Forces Command, with a four-star ROK general as commander and a four-star U.S. general as deputy commander, to facilitate the transition of operational control.[29]

As of August 2025, evaluating the fulfillment of the conditions based on the Conditions-based Operational Control Transition Plan, Conditions 1 and 2 appear to be met, while Condition 3 remains insufficient. Condition 1, securing the core military capabilities for the ROK military to lead combined defense, is assessed as largely met, comprising the information, operational, logistical, and communication capabilities required for the ROK military to lead combined defense and theater operations. Condition 2, securing essential capabilities for the alliance to respond to North Korea's nuclear and missile threats, is evaluated as met through the ROK's establishment of the "three-axis system," the creation of a Strategic Command, and the development of ROK-U.S. Conventional-Nuclear Integration (CNI) operational plans. Condition 3, the security environment on the Korean Peninsula and in the region, is assessed as requiring improvement.

A transition of operational control without thorough preparation, if war breaks out, would be a disaster. The transition of operational control must be pursued through thorough and meticulous preparation at the levels of the public, government, ROK military, and alliance.[30]

(1) Promotion Strategy at the National and Government Level

The citizens of the Republic of Korea must move beyond excessive reliance on the alliance for security and arm themselves with a spirit of self-reliant defense, believing that we will proactively protect our nation, and with the security of liberal democratic values.

When national unity is lacking, and the nation is embroiled in internal strife and falls into pacifism, external enemies have invariably invaded. Under no circumstances should internal strife lead to external conflict. Today's unstable political situation must be stabilized through politics of integration, coexistence, and cooperation.

The functions of the National Security Council must be strengthened, and a national-level war command system must be established. The functions of the National Security Council (NSC) must be significantly enhanced. When a grave crisis occurs that threatens national security and the safety of the people, the President must immediately preside over meetings and diligently pursue security policies related to national security. Furthermore, a war command system capable of fighting and winning must be established. Creating a nation capable of fighting is not only a strategy for preventing war but also a method for winning it.[31] must be established. Creating a nation capable of fighting is not only a strategy for preventing war but also a method for winning it.

The management of reserve forces and the readiness for wartime mobilization must be established. In the event of a declaration of war during a critical combat situation affecting national security, wartime mobilization readiness, including personnel and material mobilization, must be established to rapidly and accurately fulfill operational requirements such as force expansion or replenishment of losses for wartime operations by mobilizing reservists and supplementary personnel who have completed their military service.

Simultaneously, to create a stable security environment conducive to the transition of operational control, we must pursue inter-Korean political and military dialogue and peacefully manage the security environment on the Korean Peninsula through ROK-U.S.-China strategic dialogues.

(2) Military-Level Promotion Strategy for Operational Control Transition

Our military will pursue a strategy to secure air and sea superiority early in a contingency, neutralize strategic centers such as the enemy's war command, block intervention by third countries, and then secure key strategic areas through rapid maneuver warfare, including airborne and amphibious operations, to secure national borders and conclude the war.

Early acquisition of intelligence, surveillance, and reconnaissance (ISR) capabilities and deep strike forces is essential. A strategic strike system must be established by acquiring medium-range surface-to-air missiles (M-SAM), long-range surface-to-air missiles (L-SAM), and counter-artillery capabilities.

Warfighting capabilities, including command and control, intelligence assessment, operational planning, and operational sustainment, must be enhanced. Furthermore, reforming the superior command structure to conduct war is urgent. The dual military administration and military command systems must be unified by granting the Chairman of the Joint Chiefs of Staff the functions of the Combined Forces Commander, and the chiefs of staff of each service must be included in the operational command chain. This will enable the military to be reborn as a dynamic force that integrates operations, training, and personnel management.

(3) Alliance-Level Promotion Strategy for Operational Control Transition

Prior to the transition of operational control, it is necessary for the ROK and U.S. to define the interrelationships between the Joint Chiefs of Staff, Combined Forces Command, UNC, and U.S. Forces Korea. The Joint Chiefs of Staff will issue strategic directives and operational orders to the Future Combined Forces Command through the National Authority and the ROK-U.S. Security Consultative Meeting and its Military Committee. Concurrently, it will serve as the supreme command for the execution of operations against localized provocations. Combined Forces Command will develop operational plans in preparation for war, oversee ROK-U.S. combined training, and serve as the command for theater operations on the Korean Peninsula in case of contingency. The United Nations Command (UNC) will implement and enforce the Armistice Agreement during peacetime and provide forces during contingencies. Combat units deployed as part of the UNC will be tactically controlled by the Future Combined Forces Command to conduct warfare under a unified command structure. U.S. Forces Korea will maintain ROK-U.S. combined combat readiness during peacetime and perform wartime missions under the operational control of Combined Forces Command, along with U.S. reinforcement forces. This should be reflected in Strategic Directive No. 3 upon the transition of operational control.

Command Structure of the Future Combined Forces Command[32] could be considered, with a ROK Army General as Commander and the Commander of U.S. Forces Korea as Deputy Commander. The Chief of Staff would be a U.S. officer, and the Deputy Chief of Staff a ROK officer. Considering the importance of ground operations on the Korean Peninsula, a ROK General could serve as the Chief of Operations Staff, while a U.S. General could serve as the Chief of Planning Staff, considering future plans and the deployment of reinforcement forces. A ROK General could serve as the Chief of Intelligence Staff. The Ground Component Commander would be the Commander of the Ground Operations Command. Considering U.S. reinforcement air power, the Air Component Commander could be the Commander of the U.S. 7th Air Force, and the Naval Component Commander could be the Commander of the U.S. 7th Fleet, considering deployed forces including aircraft carriers. The Special Operations Component Commander could be the Commander of the ROK Special Warfare Command, and the Marine Component Commander could be the Commander of the ROK Marine Corps. The Space Component Commander could be a U.S. officer, and the Cyber Warfare Component Commander could be a ROK General.

A Military Cooperation Center will be operated under the UNC, with the UNC Deputy Commander as its head. When combat units from UNC member states are deployed, they will be tactically transferred to the Future Combined Forces Command. It will also coordinate with international organizations (IGOs) and non-governmental organizations (NGOs) that may participate in humanitarian assistance on the Korean Peninsula in case of contingency. Additionally, a strategic team will operate directly under the Commander of the Combined Forces Command to develop future strategies.

It is necessary to enhance the military's surveillance, reconnaissance, operational planning, and command capabilities to achieve a deterrence posture against North Korea and to implement and execute a roadmap for the transition of operational control based on a strong ROK-U.S. alliance.[33] At the 27th ROK-U.S. Integrated Defense Discussion (KIDD) held in Seoul on September 23-24, the ROK and U.S. defense ministries stated that they "reviewed the progress of the "Conditions-based Operational Control Transition Plan" agreed upon by the ROK and U.S. and agreed on significant progress in meeting the conditions."[34] If the second phase of FOC verification is passed in February 2026, the ROK and U.S. can discuss the target year for the transition of operational control.[35]The target year for the transfer of wartime operational control (SOTG) is set for 2028. The evaluation of the Combined Forces Command's ability to execute its mission for the SOTG transfer will be completed upon passing the third stage of Full Mission Capability (FMC) verification in the last year prior to the target year, 2027. The Ministers of National Defense of South Korea and the United States will jointly recommend the SOTG transfer to their respective presidents, enabling the transfer of wartime operational control to the South Korean military effective January 1, 2028.

5. Response to North Korea's Nuclear Challenge

North Korea's nuclear and missile threats are grave. The possibility of a preemptive strike with nuclear missiles and an invasion of the South cannot be ruled out. Comprehensive countermeasures must be devised. This requires a comprehensive response strategy, including continuous supplementation of the Korean-style three-axis system, implementation of integrated extended deterrence, automatic deployment of tactical nuclear weapons upon escalation of defense readiness, and the New Peace Strategy based on a nuclear balance on the Korean Peninsula.[36]

(1) Supplementing the Korean-style Three-Axis System

First, the Korean-style three-axis system will be supplemented. While enhancing the effectiveness of the three-axis system—comprising Kill Chain, Korea Air & Missile Defense (KAMD), and Korea Massive Punishment and Retaliation (KMPR)—for nuclear and WMD (Weapons of Mass Destruction) threats, it is essential to achieve an appropriate balance between high-value intelligence, surveillance, and reconnaissance (ISR) assets utilizing the High-Low concept for structural optimization, advanced technology assets including interceptor missiles, and conventional assets including drones. To supplement the three-axis system and reduce the sensitivity of nuclear issues, non-lethal weapon systems that can induce functional incapacitation without causing direct damage to North Korean forces, as well as cyber warfare, electronic warfare, and psychological warfare, should be actively employed.

In terms of cybersecurity, to strengthen integrated coordination and response capabilities against North Korean cyber intrusions, the Cyber Basic Law should be enacted. The Cyber Operations Command, whose functions have been weakened, should be upgraded to a Cyber Counterintelligence Command to thoroughly implement preventive measures, ensuring that military secrets or advanced technologies are not leaked to North Korea or foreign powers.[37]

(2) Implementing Integrated Extended Deterrence

Second, the Washington Declaration and integrated extended deterrence will be implemented. The Korean-style extended deterrence, agreed upon by the South Korean and U.S. presidents on April 26, 2023, must be substantively implemented. The Nuclear Consultative Group (NCG) will be operationalized, and execution plans for U.S. nuclear war and South Korean conventional war support will be developed, along with enhanced joint education and training for nuclear deterrence forces. A government-wide tabletop simulation for nuclear war operations will be conducted, and strategic assets such as strategic submarines and strategic bombers will be regularly demonstrated. Furthermore, the South Korean military's strategic strike capabilities and the ROK-U.S. 4D (Detect, Disrupt, Destroy, Defend) response concept will be integrated and developed within the scope of warfare.

Additionally, the ROK-U.S. Guidelines for Nuclear Deterrence and Nuclear Operations on the Korean Peninsula, signed by the leaders of both countries on July 11, 2024,[38]will be specified. This includes the rapid advancement of the ROK-U.S. NCG work framework, encompassing security protocols to expand information sharing between the two nations, nuclear consultation processes in times of crisis or contingency, nuclear strategy and operational planning, Conventional-Nuclear Integration (CNI) between South Korea and the U.S., South Korean conventional weapon support during U.S. nuclear operations, strategic dialogues, training, exercises, simulations, investment activities, and exercises for risk reduction.

(3) Automatic Deployment of Tactical Nuclear Weapons Upon Escalation of Defense Readiness

Third, tactical nuclear weapons will be automatically deployed upon escalation of the ROK-U.S. Combined Forces' defense readiness posture. To maintain strategic stability on the Korean Peninsula, tactical nuclear weapons will be deployed immediately when the defense readiness posture (DEFCON) is elevated due to heightened security tensions, through either rotational deployment to the Korean Peninsula during peacetime or deployment during contingencies. This requires the conclusion of a bilateral agreement between South Korea and the U.S. covering procedures for nuclear weapon use, storage, loading drills, and costs, and will proceed through stages such as the construction of Weapons Storage and Security Systems (WS3), movement of tactical nuclear weapons, and loading drills.

(4) Nuclear Balance on the Korean Peninsula through South Korea's Nuclear Armament

Fourth, a nuclear balance on the Korean Peninsula and the New Peace Security Strategy will be pursued through South Korea's nuclear armament. If the Trump administration fails to implement the Washington Declaration or if tactical nuclear weapons are not redeployed, South Korea's nuclear armament will become inevitable. This will proceed in four stages: Stage 1, establishing a command tower for nuclear armament and securing nuclear potential; Stage 2, withdrawing from the NPT in a national emergency; Stage 3, pursuing nuclear armament with persuasion and tacit approval from the U.S.; and Stage 4, achieving a North-South nuclear balance, followed by negotiations with North Korea for nuclear reduction, leading to the disposal of nuclear weapons and the signing of a peace treaty.[39]However, South Korea's nuclear armament will be pursued conditionally, contingent upon reaching an agreement with North Korea on nuclear reduction or the complete disposal of nuclear weapons simultaneously with unification.

6. Increase in Defense Contributions and Gradual Increase of Defense Budget to 4% of GDP

(1) Increase in Defense Contributions

The negotiations for the cost-sharing of U.S. Forces Korea (USFK) for the next five years, starting in 2026, have been concluded, with the total cost-sharing amount for 2026 set at 1.5192 trillion KRW, an 8.3% increase compared to 2025.[40]Adhering to this is customary and fundamental.

If further negotiations are unavoidable, it is necessary to establish the following principles:[41]First, if the USFK simultaneously performs roles in defending the Korean Peninsula and containing China, it is reasonable to adjust the share of costs by reducing the portion corresponding to the contribution to China containment, after comparing the two roles.

Second, in terms of calculating defense contributions, South Korea, like Japan, should include direct support costs such as land, water, and electricity expenses for USFK facilities, airport and highway tolls, as well as KATUSA support costs.

Third, it is necessary to highlight South Korea's higher alliance contribution compared to Japan and Germany.

① As an ally, South Korea's participation in the Vietnam War with two combat divisions, and the deployment of the Zaytun Division to Iraq and the Osino Unit to Afghanistan, is overwhelmingly differentiated from Japan's limited financial and troop support for the Iraq War and Germany's deployment to Afghanistan.

② South Korea bore 91% of the $1.2 billion cost for the relocation of the Pyeongtaek base, amounting to $1.09 billion.

③ In terms of defense spending as a percentage of GDP according to IMF standards in 2024, South Korea's GDP was $1.6466 trillion with defense spending of $46 billion (2.7%), Japan's GDP was $4.39 trillion with defense spending of $50.2 billion (1.1%), and Germany's GDP was $4.92 trillion with defense spending of $86 billion (1.8%), indicating significantly higher defense expenditure in South Korea.

④ In terms of arms purchases from the U.S. between 2008 and 2017, South Korea ranked third after Saudi Arabia and Australia, purchasing 7.6 trillion KRW ($6.731 billion) over the past decade, which is double Japan's arms purchase amount of $3.75 billion. This directly contributes to the revitalization of the U.S. economy and job creation.

⑤ Considering the economic scale and the number of stationed troops, South Korea contributes 1.5192 trillion KRW ($1.1 billion) for 28,500 U.S. troops, Japan contributes 2.0599 trillion KRW ($1.7383 billion) for 54,000 stationed troops, and Germany contributes 944.1 billion KRW ($796.7 million) for 36,000 U.S. troops stationed in Germany. When converted to defense cost-sharing as a percentage of GDP, South Korea is 0.053%, Japan is 0.034%, and Germany is 0.019%, with South Korea having the highest ratio.

Fourth, in exchange for appropriate defense cost-sharing, restrictions that hinder the enhancement of South Korean military capabilities should be lifted. This includes obtaining technological transfers through joint R&D in military science and technology between South Korea and the U.S., amending the ROK-U.S. Atomic Energy Agreement to secure tactical nuclear weapons redeployment in the Korean Peninsula theater, NATO-style nuclear sharing, and the capability for uranium enrichment and reprocessing, as well as permission to develop nuclear-powered submarines to counter the threat of Submarine Launched Ballistic Missiles (SLBM).

Fifth, negotiations must be fair and mutually beneficial. During defense cost negotiations, the appropriate increase rate should be determined, along with a maximum limit. Direct support costs, including personnel expenses, military construction and maintenance, and logistical support, should be progressively supported 100% by South Korea. The remaining requested costs, such as the deployment of U.S. strategic assets to the Korean Peninsula and the operation and maintenance of U.S. military weapons and equipment, should be borne by the U.S., while South Korea undertakes the Maintenance, Repair, and Operation (MRO) of U.S. Navy vessels.

(2) Gradual Increase of Defense Budget to 3.5%

To counter the escalating North Korean nuclear and missile threats, address unspecified threats from neighboring countries, and prepare for changes in U.S. foreign defense policy and military operations, it is crucial to build independent defense capabilities. Stable defense budget assurance, transcending political administrations, is essential. The defense budget must be recognized as a public good that benefits the entire nation, as it is absolutely critical for national survival. Defense reform for self-reliant defense and enhancement of defense capabilities is not an option but a necessity.[42]

In the medium to long term, it is desirable to gradually reduce reliance on the U.S. for South Korean defense. To secure the necessary financial resources for this, the defense budget must be managed meticulously and efficiently. Recognizing that there are no eternal allies in international politics, it is imperative to build self-reliant defense capabilities that allow South Korea to stand independently at any time. It is essential to foster an independent military capable of independently conducting warfare without U.S. alliance support by gradually replacing U.S.-dependent capabilities.

As of 2025, South Korea's defense budget is 2.67% of GDP (GDP $1.6466 trillion, defense budget $46 billion). Considering the need to augment capabilities to counter North Korean threats for the transfer of wartime operational control, which is estimated to cost 21 trillion KRW, it is necessary to gradually increase the defense budget to 3.5% in conjunction with the SOTG transfer.[43]

III. Conclusion and Policy Recommendations

The future vision of the ROK-U.S. alliance, presented at the Korean Peninsula, Northeast Asian, and global levels, is as follows: At the Korean Peninsula level, the vision is denuclearization and the establishment of a peace regime. At the Northeast Asian level, it is the institutionalization of regional security cooperation. At the global level, it is the construction of a liberal international order.

To realize this vision, the following policy recommendations are proposed:

First, to establish a peace regime on the Korean Peninsula, it is proposed to establish a Presidential Committee for a Unified Korea Alliance. This committee, composed of ROK-U.S. policymakers and experts, would develop a vision for a unified Korea, devise strategies for its realization, and ensure the ROK-U.S. alliance plays a leading role in establishing a peace regime on the Korean Peninsula.

Second, it is proposed to establish a SOTG Transfer Promotion Committee directly under the command of the Commander-in-Chief to advance the SOTG transfer at a national level. This committee would review the conditions for SOTG transfer, set the target year, engage in strategic communication with the public, issue negotiation guidelines to the U.S., identify actions for the public, government, National Assembly, military, and allies, conduct quarterly reviews of SOTG transfer progress, establish a war command system, increase the defense budget, reorganize the upper command structure, and formulate security plans post-SOTG transfer.

Third, an agreement should be reached with the U.S. to ensure that when USFK forces are redeployed to areas outside the Korean Peninsula due to contingencies, they can be withdrawn only after or simultaneously with the deployment of alternative forces.

Fourth, to define the roles of the alliance, it is proposed to establish a ROK-U.S.-Japan Military Cooperation Task Force composed of strategic planners and experts from the ROK Joint Chiefs of Staff, U.S. Indo-Pacific Command, and the Japan Joint Staff Office. By simulating scenarios such as a war on the Korean Peninsula, a war in Taiwan, or simultaneous conflicts on the Korean Peninsula and in Taiwan, the roles and responsibilities of South Korea, the U.S., and Japan for each contingency can be identified.

Fifth, in consultation with the U.S., a system for the automatic deployment of tactical nuclear weapons should be established for situations where the defense readiness posture is escalated due to heightened tensions on the Korean Peninsula. If North Korea attacks with tactical nuclear weapons using hypersonic missiles, extended deterrence has its limits, necessitating extraordinary measures. A bilateral agreement between South Korea and the U.S. covering procedures for nuclear weapon use, storage, loading drills, and costs must be concluded, and this will proceed through stages such as the construction of Weapons Storage and Security Systems (WS3), movement of tactical nuclear weapons, and loading drills.

The spirit of alliance, which recognizes a military attack in the Pacific region as an attack on the allied nation of South Korea and calls for a joint response; the transfer of ROK-U.S. wartime operational control; understanding the logic behind the U.S.'s transformation of its global military strategy as an ally; respecting the necessity of strategic flexibility for USFK; and the immediate deployment of tactical nuclear weapons when tensions on the Korean Peninsula escalate and the defense readiness posture is raised, given that North Korea's nuclear weapons pose an existential threat to the Republic of Korea; and promoting increased defense spending to fulfill the role of an expanded alliance, will provide an opportunity for the ROK-U.S. alliance to evolve into a reciprocal and symmetrical alliance. ■

[1]"U.S. Formalizes 'ROK-U.S. Alliance Modernization' Talks... 'Need for South Korea to Expand Defense Burden,'" Chosun Ilbo, July 24, 2025.

[2] Chun Jae-sung, "The New Government's North Korea Strategy: Key Variables and Response Strategies," Joint Academic Forum hosted by the Choi Jung-hyun Institute for Academic Studies, East Asia Institute, and Seoul National University Institute for National Future Strategy, "Global Complex Crisis: South Korea's Foreign and Security Strategy Directions," July 24, 2025, Korea Foundation Conference Hall.

[3] Lee Jung-gu, "North Korea's 'Hostile Two-State Theory' and the Outlook for Inter-Korean Relations," Tongil Jeongchaek Yeon-gu (Journal of Korean Unification Studies), Vol. 33, No. 1 (2024).

[4] SIPRI, SIPRI Yearbook 2025 (Stockholm: SIPRI, 2025), p. 182.

[5] Bruce W. Bennett, Kang Choi, Myong-Hyun Go, Bruce E. Bechtol, Jr., Jiyoung Park, Bruce Klingner, and Du-Hyeogn Cha, Countering the Risks of North Korean Nuclear Weapons (Santa Monica: RAND, April 12, 2021).

[6] BRICS was launched in 2002 with Brazil, Russia, India, China, and South Africa as its core members. With the addition of Saudi Arabia, Egypt, United Arab Emirates, Ethiopia, Indonesia, and Iran in 2024-2025, the number of member states has reached eleven.

[7] Bang Gil-joo, “A Study on the International Order Through the Concept of a New Cold War,” in Lee Kwan-se, Bang Gil-joo, Choi Young-jun, Cho Sung-ryeol, Lee Seung-joo, Choi Yong-hwan, and Jeon Jae-seong, eds., *Is the Era of a New Cold War Dawning?* (Seoul: Institute for Far Eastern Studies, Kyungnam University, 2024).

[8] Park Dong-chan, *The Korean War Through Statistics* (Seoul: War Memorial of Korea, 2014).

[9] Institute of Defense History, *Statistics on the Damages of the Korean War* (Seoul: Institute of Defense History, 1996), p. 135.

[10] Kim Choong-hwan, “Results of the Busan General Assembly and the Role of the National Assembly,” *International Development Cooperation*, no. 4 (2011), p. 51.

[11] Chung Kyung-young, “Conclusion of a Peace Treaty and the Future of the U.S. Forces Korea,” EAI Issue Briefing, July 24, 2018.

[12] Chung Kyung-young, *Peace Creation: The ROK-U.S. Alliance and Peacebuilding* (Paju: Hanul Academy, 2020), pp. 150-184.

[13] The White House, “Leaders’ Joint Statement in Commemoration of the 70th Anniversary of the Alliance between the United States of America and the Republic of Korea,” April 26, 2023. https://bidenwhitehouse.archives.gov/briefing-room/statements-releases/

[14] Chung Kyung-young, “Building a Military Security Cooperation Regime in Northeast Asia: Feasibility and Design,” PhD Dissertation, University of Maryland (2005), pp. 345-348.

[15] Syngman Rhee Memorial Hall, “Original Text of the ROK-U.S. Mutual Defense Treaty (October 1, 1953)” Providing Achievements and Research Materials of the Founding President (Accessed: 2025. 8. 20).

[16] Choi Yong-ho, *The Vietnam War and the Korean Military* (Seoul: Bora, 2010).

[17] “‘The Navy’s Mobile Fleet Command, the Core of the Maritime Three-Axis System, Sets Sail,’” *The Defense Daily*, February 3, 2025: The Jeju Mobile Fleet Command, established on February 3, 2025, is tasked with protecting maritime traffic routes, maintaining readiness against North Korea, and conducting escort missions for the Somali Sea Detachment (Cheonghae Unit). It operates ten destroyers, including the 8,200-ton Aegis destroyer (DDG-Ⅱ) and the ROKS Jeongjo the Great, as well as the 10,000-ton combat support ship (AOE-Ⅱ) Soyang.

[18] “‘Stronger Together’—A Unified ROK-U.S. Marine Corps Joint Exercise Underway,” *Asia Today*, August 6, 2025: The joint landing exercise is conducted annually by the ROK and U.S. Marine Corps as a core training event of KMEP (Korea Marine Exercise Program). KMEP is a U.S. Marine Corps deployment training program to the Korean Peninsula aimed at enhancing the combined operational capabilities and interoperability of the ROK and U.S. Marine Corps. Approximately 1,500 U.S. Marines from III-MEF 3rd Division stationed in Okinawa participate, sharing practical combat skills and tactics with personnel from the ROK Marine Corps 1st Division, 2nd Division, 6th Brigade, Yeonpyeong Unit, Air Wing, and Logistics Group.

[19] The White House, “The Spirit of Camp David: Joint Statement of Japan, the Republic of Korea, and the United States,” (Aug 18, 2023).

[20] Ministry of Foreign Affairs, *2024 Foreign Affairs White Paper: International Affairs and Diplomatic Activities in 2024* (Seoul: Ministry of Foreign Affairs, 2025).

[21] Korean Culture and Information Service, “Explanatory Materials Regarding ‘Strategic Flexibility,’” January 23, 2006.

[22] “From the Korean Peninsula to a Multidomain Operations System in the Indo-Pacific,” The World Is Watching Korea: The Reason Why the Landscape of U.S. Forces Korea Has Been Reversed 180 Degrees (Accessed: 2025. 8. 19).

[23] Kim Jeong-seop, “Trump’s Trilemma and Active Alliance Transformation,” Jointly hosted by the Choi Jong-hyun Academy, the East Asia Institute, and the Seoul National University Institute for National Future Strategy, “Global Complex Crisis: Diplomatic and Security Strategy Directions for the Republic of Korea” Academic Forum, July 24, 2025, Korea Foundation Conference Hall.

[24] “Transition of Wartime Operational Control: Taking a Shortcut Could Jeopardize Korean Peninsula Readiness,” *Chosun Ilbo*, August 11, 2025.

[25] Alex Horton and Hannah Natanson, “Secret Pentagon memo on China, homeland has Heritage fingerprints,” The Washington Post, March 29, 2025.

[26] “National Committee Announces ‘5-Year National Operation Plan’… ‘Transition of Wartime Operational Control Within Term,’” *New Daily*, August 13, 2025.

[27] “In Case of a ‘Taiwan War,’ Korea Must Defend Itself… The U.S. Will Also Respect Korea’s Judgment,” VOA, January 20, 2024.

[28] Ministry of National Defense, “Three Conditions for the Transition of Wartime Operational Control,” Korea Policy Briefing www.korea.kr (Accessed: 2025. 7. 30).

[29] “Resolution of the Department of Defense of the United States of America and the Ministry of National Defense of the Republic of Korea: Guiding Principles Following the Transition of Wartime Operational Control,” https://kr.usembassy.gov/ (Accessed: 2025. 3. 28).

[30]Jeong Gyeong-young, "Wartime Control Transfer and National Security" (Seoul: Maebong Publishing, 2023), pp. 105-129.

[31]Ha Jeong-yeol, "A Review of the Concept of the President's War Command," Korea Strategy Research Institute Policy Research Report, 2010. 9: War command refers to the command capability and technology that organizes national capabilities by integrating, coordinating, and controlling national strategy and military strategy, which is exercised to deter war during peacetime and achieve victory in case of emergency.

[32]Jeong Gyeong-young, "Wartime Control Transfer and North Korea's Nuclear Comprehensive Response Strategy and Military Structure Reform," compiled by the Korea Nuclear Security Strategy Forum, "Korea's Nuclear Security Project 1: Justification and Promotion Strategy" (Seoul: Blue & Note, 2025), pp. 343-375.

[33]"National Planning Committee, Wartime Control Transfer: Need for Review Between Integrated and Parallel Types," Kyunghyang Shinmun, August 13, 2025.

[34]"US-ROK Defense Ministries Agree on Significant Progress in Meeting Conditions for Wartime Control Transfer," Yonhap News, September 24, 2025.

[35]"Government Plans to Link Wartime Control Transfer to US Demand for Increased Defense Spending," Donga Ilbo, August 7, 2025.

[36]Jeong Gyeong-young, "Wartime Control Transfer and North Korea's Nuclear Comprehensive Response Strategy and Military Structure Reform," compiled by the Korea Nuclear Security Strategy Forum, "Korea's Nuclear Security Project 1: Justification and Promotion Strategy" (Seoul: Blue & Note, 2025), pp. 343-375.

[37]Kim Hee-cheol, "North Korea's Cyber Hackers Steal 810 Billion Won: What is Our Countermeasure?," Academic Conference on "Recent Status and Prospects of North Korea's ICT" jointly hosted by Hanyang University Institute for National Strategic Studies and Security Cooperation Institute (November 30, 2022).

[38]The White House, "Joint Statement by President Joseph R. Biden of the United States of America and President Yoon Suk-yeol of the Republic of Korea on US-ROK Guidelines for Nuclear Deterrence and Nuclear Operations on the Korean Peninsula," (July 11, 2024).https://bidenwhitehouse.archives.gov/briefing-room/statements-releases/

[39]Jeong Seong-jang, "Why We Must Become a Nuclear State: The Best Security Strategy to Prevent War in the Era of Hegemonic Competition" (Seoul: Medici Media, 2023), pp. 119-139.

[40]"2026 ROK Share for US Forces Korea to Increase by 8.3% to 1.5 Trillion Won from Next Year," Chosun Ilbo, October 5, 2024.

[41]Jeong Gyeong-young, "Peace Creation: ROK-US Alliance and Peacebuilding" (Paju: Hanul Academy, 2020), pp. 184-191.

[42]Jeon Je-guk, "Defense Budget Demand Forecast and Securing Measures," "Defense Policy Direction of the New Government" (Seoul: Korea Strategy Research Institute, July 15, 2017), p. 138.

[43]"Government Plans to Link Wartime Control Transfer to US Demand for Increased Defense Spending," Donga Ilbo, August 7, 2025.

■ Jeong Gyeong-young_Adjunct Professor, Graduate School of International Studies, Hanyang University.

■ Responsible Editor: Oh In-hwan_Senior Research Fellow, EAI; Jeong Jong-hyuk_Research Fellow, Korea National Diplomatic Academy
    Inquiries: 02 2277 1683 (ext. 202) | ihoh@eai.or.kr