Efforts to develop the South Korea-U.S. alliance into a comprehensive strategic alliance on a global scale are not new. In 2008, South Korea and the United States agreed to develop the alliance into a “strategic alliance for the 21st century.” They adopted the “Joint Vision for the Alliance of the Republic of Korea and the United States of America” in 2009. At the 2013 summit, the 60th anniversary of the Joint Declaration proposed a “future-oriented alliance.” The two countries reiterated their shared values and mutual trust in the “Joint Prospectus on the Status of U.S.-ROK Relations: The U.S.-ROK Alliance: Shared Values, New Horizons” in 2015. At the May 2021 summit, various areas of cooperation were laid out in detail, and in 2022 and 2023, the two countries emphasized the development of the alliance into a “global comprehensive strategic alliance.”
As many have pointed out, the South Korea-U.S. alliance is no longer limited to the Korean Peninsula; in fact, it never was. The alliance already specified its commitment and role in the “Pacific” region in Article 3 of the South Korea-U.S. Mutual Defense Treaty, signed in 1953. More than 70 years later, the regional role of the alliance is being emphasized even more. The effects of armed conflict have rippled across borders, and strategic simultaneity has become commonplace. The areas of potential conflict have expanded significantly, including cyberspace and outer space, and the ramifications of advanced weapons systems, including nuclear weapons, are not limited to the national level. Even without mentioning non-traditional threat responses, these factors necessitate an expansion of alliance cooperation. In the era of complex security, it is time to go beyond the words of a “global comprehensive strategic alliance” and materialize it into action.
Prerequisites for Expanding the Alliance
The significance of the South Korea-U.S. alliance has always been acknowledged, yet it is challenging to argue that it has evolved into a truly global and comprehensive alliance. This is because the instability of the international situation, the fragmentation of domestic politics, and the constraints of state capabilities have forced alliance policymakers to pick their priorities. It was also necessary to address issues such as differing threat perceptions within the alliance, discrepancies in role expectations, and concerns about mutual confidence. And even now, when the South Korea-U.S. alliance is in great demand, there are basic problems that the alliance must consider.
First, there is a need to strengthen the comprehensive nature of the alliance so that South Korea and the United States have a common threat perception. Even though Seoul and Washington might have different threat perceptions based on their own national interests, both sides need to get on the same page regarding the regional threat assessment and see where they overlap. From the point of view of South Korea, of course it should promote its national interests, but it should not focus solely on the North Korean threat and demand U.S. support. On the other hand, the United States should not impose its own global strategy on South Korea. This requires mutual understanding and an inclusive approach to the security situation and strategic needs facing the other side.
It is necessary to define the scope of the alliance’s commitments to defend common values in the region, and to promote regional multilateral security cooperation to reconcile differences and encourage cooperation among regional countries.
Second, the South Korea-U.S. alliance must be a dynamic one that responds to complex regional threats by fulfilling mutual expectations regarding alliance roles. The combined defense posture of the South Korea-U.S. alliance is optimized for security on the Korean Peninsula. For the three commands – the South Korea-U.S. Combined Forces Command, the United Nations Command (UNC), and the U.S. Forces in Korea (USFK) – to fulfill their comprehensive roles and scopes, more dynamic military planning procedures and systems are needed. This should also be linked to the expansion of geographical space, as well as cooperation in the space and cyber domains, and on defense technology.
Third, it is necessary to achieve “integrated deterrence” to counter day-to-day competition in the gray zone and potential competitors in the long term. To deter various threats in the region, Washington has tried to establish lattice-like security cooperation, including South Korea-U.S.-Japan security cooperation and Australia-Japan-Philippines-U.S. cooperation. Even though these minilateral groupings have different objectives and functions in the region, they have a common foundation: Washington is attempting to make a web for regional security.
To achieve dominance in the competitive space under the level of armed conflict, it is necessary to maintain a solid alliance that is not swayed by external circumstances. As we can see from the case of deployment of the THAAD missile defense system in 2016, if China or North Korea exerts pressure, it poses a heavy burden on the South. The South Korea-U.S. alliance will need to achieve resilience and integration through latticework security cooperation in order to maintain its strategic advantage in both long-term and day-to-day competition.
Objectives for the Regional Role of the Alliance
Given the complex geopolitical situation, the South Korea-U.S. alliance will have no choice but to expand its role beyond the security of the Korean peninsula. The South Korean and U.S. governments must have honest discussions about what the U.S. military in Korea and the alliance can do beyond the Korean Peninsula in the future. The role of the South Korea-U.S. alliance can be examined on three levels.
First, the most important role of the South Korea-U.S. alliance in the future will be to ensure security and regional stability on the Korean Peninsula. The alliance has served as a deterrent to North Korea and its neighbors, as well as preventing accidental clashes in the region. In particular, the USFK possesses its own intelligence collection and early warning capabilities, guarantees automatic U.S. intervention, and serves as a base force for the stable reinforcement of the U.S. military and UNC force providers in case of emergency. Even in the event of a formal declaration of the end of the war, a peace treaty, and even reunification of the Korean Peninsula, joint efforts by the South Korea-U.S. alliance would be required to continue to maintain security.
Second, the alliance has a role in building peace on the global level. The alliance is not limited to the geographic space of the peninsula alone. Since the end of the Cold War, the South Korea-U.S. strategic alliance aims to be an “alliance of values” for the realization of the universal values of freedom and human rights; an “alliance by trust” for interdependence encompassing the fields of diplomacy, security, economy, and culture; and a “peace-building alliance” that contributes to peace and prosperity on the Korean Peninsula as well as in East Asia and the world. The South Korea-U.S. alliance will be able to play a role in building peace on a global scale, starting with alleviating regional security dilemmas and preventing the occurrence of conflicts.
Third, the South Korea-U.S. military alliance serves as a key link to a healthy South Korea-U.S. relationship in the fullest sense. Until now, the South Korea-U.S. alliance has been primarily aimed at joint military responses to common threats, but the alliance does not exist solely on the military level. In response to comprehensive security threats, the alliance has developed into a comprehensive relationship that not only pursues various security interests but also has close, interdependent cooperation in the fields of politics, diplomacy, economy, and culture. The alliance should continue to develop into a multi-layered cooperative relationship that encompasses civil society and business in the future.
The Alliance’s Contributions on the Regional Level
In order for the Trump administration’s “America First” policy to gain momentum in East Asia, paradoxically, cooperation from allies is significant. To quote Henry Kissinger, it is “lucky” that the United States has an ally on the Korean Peninsula. South Korea can contribute geopolitically, geostrategically, and geoeconomically to the U.S. Indo-Pacific Strategy, originally formulated during the first Trump administration. Therefore, the alliance can make a decisive contribution to the security of the United States and South Korea.
At the military level, the South Korea-U.S. alliance can fulfill this multi-layered and complex role by pursuing a higher level of interoperability, military efficiency, and flexibility. For the past 70 years, the South Korea-U.S. combined defense posture has ensured the security of the Korean Peninsula by deterring a re-invasion by North Korea. Integrated deterrence can be achieved across the entire spectrum by enhancing interoperability in expanded domains such as cyberspace and outer space, geographically expanded space, and in the gray zone (sub-conflict phases).
Second, the alliance can ensure effective military campaigning in the competition continuum. Opponents such as North Korea, China, and Russia are actively using the gray zone while armed with nuclear weapons. The Korean Peninsula is a decisive point not only geographically, but also in terms of national strength and will. Naturally, the USFK is a base that exists within the First Island Chain and is an important “strategic position” for the U.S. military posture. Thanks to its alliance with South Korea, the U.S. can overcome the “tyranny of distance.”
Third, the alliance can strengthen collective resilience. The naval power competition between the U.S. and China in the Indo-Pacific region is already a matter of grave concern, and efforts have begun to combine regional alliances such as South Korea and Japan to achieve joint superiority. In areas such as strategic transportation, refueling, and maintenance, repair, and operating, which have been presented as vulnerabilities in a variety of crisis scenarios, the South Korea-U.S. alliance can play an all-too-important role. This resilience acts as a powerful deterrent power to the opponent’s coercion.
Fourth, to achieve long-term competitive advantage, what is important is “integrated innovation” through military-technical cooperation. The United States can no longer dominate in all technologies, so it must work with allies who have competitive advantages in different areas. The KF-21 is a good illustration. The KF-21 fighter jet, jointly developed by South Korea and the U.S., will help the United States focus on cutting-edge technology for the next-generation fighter jet and secure strategic space for South Korea to transition from fourth-generation to fifth-generation aircraft. This will boost the competitiveness of both allies, increase the resilience of global supply chains, modernize the rules and order of the global economy, and minimize the security risks posed by dual-use technologies. Through these efforts, ultimately, the South Korea-U.S. alliance can evolve to the next level of interdependence based on interoperability.
Policy Recommendations
Let’s assume for a minute that President Trump actually does want to project peace through strength and bolster the U.S. position and security in the Indo-Pacific area. To do so, he must have allies.
The South Korea-U.S. alliance can no longer stay on the Korean Peninsula, and it is difficult for a bilateral alliance to achieve security on its own. Fulfilling a regional role and engaging with other U.S. allies is now an essential task. We propose several policy proposals for these roles and tasks.
First, there is a need for consultation for joint planning on regional issues. The alliance’s consultative bodies, including the newly created Nuclear Consultative Group, are already complex and saturated, and it is necessary to optimize them according to evolving threats and the alliance’s expanding role. It also means that the regional responsibility of South Korea to receive information from the U.S. increases, as information must be shared at the local level. Combined military planning procedures, systems, and institutions are needed to jointly respond to regional issues, including a Taiwan Strait crisis.
Second, we need to think about the military posture at the regional level. To do this, it is necessary to share information about the U.S. military’s bases and posture in the Indo-Pacific region and to consider the role of South Korea in the overall architecture. To integrate the operational concepts of each of these services, the joint operation concept that originated from Air-Sea Battle has been developed into the Joint Concept for Access and Maneuver in the Global Commons and Joint All-Domain Operations. Within this framework, South Korea is also making efforts to keep pace with the changes. From Seoul’s point of view, national interests will come first in the short term, but if the long-term interests of the alliance are taken into account, South Korea can play a prospective role.
Third, there is a need for systematic integration of bilateral and multilateral combined exercises. These should be broadened and deepened with an eye toward interoperability. It would be better to make the joint exercises truly joint, not the U.S.-run shows, by incorporating joint planning and intel sharing. The U.S.-led combined exercises are very active on the Korean Peninsula and in the region and send a strong message of deterrence, but the participation of South Korea is still at a low level compared to expectations for its role. Of course, if this comes to pass Seoul must be prepared to face unnecessary threats by pressuring China or to increase the risk of becoming involved in China-U.S. competition. However, in order for the South Korea-U.S. alliance to develop and validate common planning, formation, posture, capabilities, and systems, a more systematic and integrated joint exercise is urgently needed.