Views expressed in this article are those of the author and not necessarily reflective of Sasakawa USA or the NEXT Alliance Initiative.
Established in 1957, the sub-unified commands of US Forces Japan (USFJ) and US Forces Korea (USFK) are no longer relevant to today’s strategic threat environment in Northeast Asia. They should be combined into one sub-unified command to better reflect the interlocking security challenges of that region.
The Regional Security Environment – Then and Now
Much has changed in the sixty-six years since Far East Command (FECOM) was split into two sub-unified commands. Then, regional US forces focused on two separate, though related, strategic problems that required a different mix of combat capabilities under separate command structures alongside two allies who retained significant hostility towards one another. Strategists believed that the resumption of war on the Korean peninsula could be contained there, that the military bases in Japan would primarily provide a rear security and logistics function, and that the risk of spill-over into other areas in Northeast Asia could be mitigated. Although, fortunately, these assumptions were never tested, they remained reasonable up until the early part of this century. Today, they are much less convincing.
It is likely that a major conflict on the Korean peninsula, or Northeast Asia in general (including Taiwan and the East China Sea) would involve active operations throughout the entire region. Moreover, the military capabilities of both Japan and the Republic of Korea (ROK), as well as their respective commitments to collective self-defense, have strengthened over the years. Both militaries, therefore, will likely become involved in any major regional conflict alongside US forces. The United States will expect their active participation in a major conflict in the spirit of upholding their mutual security treaty commitments. Finally, the nationalist hostility between Japan and the ROK, while still present, has declined considerably under their current leadership – so much so that security cooperation between these two neighbors is becoming more common. Simply put, the division of Northeast Asia into two geographic sub-unified commands no longer reflects the strategic environment of this vital region.
The United States should combine USFJ and USFK into a new regional sub-unified command, US Northeast Asia Command (USNEACOM). USNEACOM should be a sub-unified command of US Indo-Pacific Command (USINDOPACOM). It should exercise operational control (OPCON) over all forward deployed US forces in both Japan and the ROK. This realignment will acknowledge the greater roles and increased capabilities of Japan Self-Defense Forces (JSDF) and ROK Armed Forces, foster closer integration of the US-Japan Alliance and US-ROK Alliance, and encourage greater trilateral security cooperation between the United States, Japan, and the ROK. Finally, it will increase the collective capacity of our allied forces without increasing the overall force structure by creating a latticework of mutually reinforcing capabilities between three of the most powerful military forces in the region.
Lineage and History of USFJ and USFK
The lineage of USFJ and USFK began in January 1947 with the establishment of FECOM. FECOM’s mission was to perform occupation duties in Japan, Korea below the 38th parallel, and other recently liberated areas throughout East Asia. Pacific Command (PACOM) was also established to maintain security over all other Pacific areas not assigned to FECOM. FECOM was under the command of the US Army and PACOM was under the command of the US Navy. This command arrangement was in large part a post-war continuation of the Army/ Navy rivalry that factored prominently throughout the Pacific War. This rivalry would persist to complicate future changes to the Unified Command Plan (UCP).
At the outset of the Korean War in July 1950, the United Nations Security Council established the United Nations Command (UNC) to direct combat operations of all United Nations forces on the Korean Peninsula. The president assigned the FECOM commander as the UNC commander. A year later, the Joint Chiefs of Staff (JCS) reassigned the Philippines, Formosa (Taiwan), and most other outlying islands not a part of Japan or Korea to PACOM over strong objection from the FECOM commander.
In 1956, the JCS undertook a major reorganization of Pacific area commands, but there was sharp disagreement between the US Army who wanted to enlarge FECOM and the other services who wanted to disestablish it. The Secretary of Defense resolved this dispute in favor of the other services. Effective July 1957, the revised UCP disestablished FECOM and divided its former command responsibilities into two new sub-unified commands, USFJ and USFK. USFJ came under the command of a US Air Force three-star general while a US Army four-star general was dual-hatted as commander of USFK and UNC. Both USFJ and USFK became sub-unified commands under PACOM. This is the basic command arrangement that endures to this day.
The US Army, however, never acquiesced in its loss of prestige and power relative to the other services by the dissolution of FECOM and enlargement of PACOM over the subsequent years. Throughout the Cold War, and even after, the US Army proposed various revisions to the UCP for a new Northeast Asia Command, which was essentially a resurrection of FEACOM itself or otherwise a sub-unified variant of that former command.
Strategic and political considerations were, however, important reasons for maintaining separate sub-unified commands. Strategically, USFJ and USFK had two distinct missions that had little overlap. Furthermore, the differences in roles and responsibilities of US forces in relation to their respective host nation forces were incompatible between the two commands. Finally, the governments of both Japan and the ROK would have opposed combining these commands out of political considerations related to the historical animosity between these two nations. A consensus gradually developed among members of the JCS that Korean unification, which would drastically alter the mission of USFK, would have to occur first before a Northeast Asia Command could be established.
Recent changes in the security environment of the Indo-Pacific region have, however, changed the strategic and political calculus in a way that favors combining USFJ and USFK into one sub-unified command. USFK is evolving towards a posture of power projection beyond the Korean Peninsula in a manner increasingly like USFJ’s role in Japan. Japan and the ROK have come to realize that they share mutual security challenges that require greater security cooperation between their military forces. Furthermore, the United States has all but abandoned its bilateral “hub-and-spokes” East Asian security architecture, which prevailed during and for decades after the Cold War, in favor of an interlocking web of regional security institutions. Together, these developments demand a more comprehensive approach towards our forward deployed defense posture in Northeast Asia, one which deals with the region as one integrated whole.
The Rationale for USNEACOM
Established in 1957, the current sub-unified command structure has not kept pace with the rapid changes in Northeast Asia’s security environment. USFJ does not have OPCON over US forces in Japan. Although it coordinates joint exercises and joint training, USFJ primarily serves an administrative role for peacetime coordination of relationships between US forces and the government of Japan. As US forces have increased their operational coordination with JSDF, this has been problematic because there is no joint operational command in Japan that represents all US forces. Instead, USINDOPACOM, headquartered in Hawaii, exercises joint operational command. Consequently, each component commander coordinates separately with their JSDF counterparts.
With the release of Japan’s 2022 National Defense Strategy, Japan announced the future establishment of a permanent Joint Headquarters to unify command of Japan’s ground, air, and naval forces. Lack of a similar organization to represent US forces forward deployed in Japan will further complicate coordination efforts with JSDF. Because of this, the Department of Defense (DOD) is considering the establishment of a joint command, either by operationalizing USFJ or by creating a separate joint operational command headquarters alongside USFJ. Moreover, the US Senate recently included language in the 2024 National Defense Authorization Act (NDAA) that will require DOD to explore ways to modify the current command structure in Japan to better coordinate military operations and compliment Japan’s new Joint Headquarters.
In contrast, USFK does have OPCON over US forces. The USFK commander is dual-hatted as commander of ROK/US Combined Forces Command (CFC), which is a binational command established in 1978 to defend the ROK from a potential North Korean attack. The 2007 agreement for transfer of CFC to a ROK general has been delayed twice, ostensibly over concerns by the US Army that the ROK Armed Forces may not be capable of exercising combined command during a contingency. The ROK government, however, remains firm in its desire to implement this plan because of the issue of sovereignty over its armed forces. An impetus may be necessary on the US side to force the implementation of this plan.
Establishment of USNEACOM will provide the impetus for allowing the ROK Armed Forces to assume a greater role in their own defense and establish a joint command in the region that has the operational authority to coordinate with Japan’s new Joint Headquarters. USNEACOM will have OPCON over all US forces forward deployed in Japan and Korea. It will provide US forces forward deployed in Korea the strategic flexibility to take a more active role in regional security beyond the Korean Peninsula. Moreover, it will enable those forces to integrate with US forward deployed forces in Japan to increase overall capabilities in Northeast Asia without increasing regional force structure. Furthermore, it will facilitate greater trilateral coordination between the United States, Japan, and the ROK. Most importantly, it will provide unity of command at the regional level over all US forces in Northeast Asia, which will enhance cohesion of the joint force to more effectively deter or defeat any reginal adversary.
Service Branch Objections and Allied Concerns
The proposal to establish USNEACOM will, however, generate considerable controversy over objections from service branches who may perceive a loss of power and influence. Although unity of command is an enduring military principle that lies at the heart of COCOM organization, COCOMs are, however, composed of service component forces that are jealous of retaining their basic roles and functions. This incentivizes them to demand greater service autonomy or to seek outright command of the joint force. Major changes to the UCP have been fraught with conflict between the principle of unity of command, service autonomy, and the number of command billets assigned to each service. Establishment of USNEACOM will eliminate a US Army four-star command, US Air Force three-star command, and replace it with a single sub-unified commander from either one or the other services. Like most bureaucratic organizations, military service branches often define their own organizational interests as being the same as the national interest. Consequently, they seek to retain or gain as much power and influence as possible from any organizational change. Either the US Army or US Air Force, or both, are likely to resist such a change if they are not assigned leadership over the new command or otherwise compensated elsewhere within the UCP.
Allied partners are sensitive to the political and strategic implications of any major change in the organization of US forces stationed within their sovereign territory. Organizational consolidations typically elicit concerns about diminished capabilities and decreased commitments. Furthermore, the ROK may be reluctant to associate US security commitments to their nation with security commitments to Japan, and vice versa. They may both fear that realigning US forward deployed forces stationed in their countries under one command will increase the risk of entrapping them in an unwanted conflict. Japanese strategists realize, however, that the security of Japan depends on the security of the ROK. Similarly, the security of the ROK would not be possible without the deterrent capability of military forces stationed in Japan. Both are strategically interdependent. DOD must work closely with the Department of State to negotiate the specifics of any organizational change in forward deployed forces and how those changes will enhance the security interests of both nations.
The structure of the UCP must remain relevant to the rapidly changing security environment now unfolding in Northeast Asia. The division of this region into two geographic sub-unified commands is no longer relevant to the interlocking security challenges faced by the United States and its two most important allies in the region. The establishment of USNEACOM will transform a divided command structure into a unified joint/allied force to more effectively deter or defeat any challenge to the regional status quo. Moreover, it will foster closer cross alliance coordination and increase the collective capacity of our forces in cooperation with two of the most powerful militaries in the region. Finally, it will provide a model for the further integration of other regional alliances towards a more unified East Asian security cooperative.
Shawn D. Harding holds a Master of International Public Policy (MIPP) from Johns Hopkins University’s School of Advanced International Studies (SAIS) and is currently a Doctor of International Affairs (DIA) Candidate. His research focuses on US-Japan bilateral security cooperation and host nation basing. Mr. Harding is a former program manager for the Defense Policy Review Initiative (DPRI) in Iwakuni, Japan. He possesses over ten years’ experience managing security cooperation programs in coordination with our allied partners across the globe.
Shawn D. Harding wrote in his own personal capacity. The views and interpretations expressed by the author are solely his own.
The US-Japan NEXT Alliance Initiative is a forum for bilateral dialogue, networking, and the development of joint recommendations involving a wide range of policy and technical specialists (in and out of government) to stimulate new alliance connections across foreign, security, and technology policy areas. Established by Sasakawa Peace Foundation USA with support from the Nippon Foundation, the goal is to help improve the alliance and how it serves shared interests, preparing it for emerging challenges within an increasingly complex and dynamic geostrategic environment. Launched in 2021, the Initiative includes two overlapping lines of effort: 1) Foreign & Security Policy, and 2) Technology & Innovation Connections. The Initiative is led by Sr. Director James Schoff.
 Edward J. Drea et al., History of the Unified Command Plan, 1946-2012 (Washington, DC: OCJCS Joint History Office, 2013), 9-11, https://www.jcs.mil/Portals/36/Documents/History/Institutional/Command_Plan.pdf.
 Ibid., 18-19.
 Ibid., 2, 31-33, 48, 51-52, 62-63, 69; John H. Tilelli and Susan Bryant, Northeast Asian Regional Security: Keeping the Calm (Arlington, VA: Association of the United States Army, 2002), 41-42, https://www.ausa.org/sites/default/files/RAMP-2002-Northeast-Asian-Regional-Security-Keeping-the-Calm.pdf.
 Drea et al., 62; David Shin, “A Cautionary Report: Resilience of the U.S.-ROK Alliance During the Pro-North Korea Engagement Era of Progressive Rule in South Korea,” North Korean Review 15, no. 2 (Fall 2019): 76, https://www.jstor.org/stable/26915826.
 Drea et al., 73.
 U.S. Library of Congress, Congressional Research Service (CRS), U.S.-South Korea Relations, by Mark E. Manyin, et al., R41481 (2022), 20-21, https://crsreports.congress.gov/product/pdf/R/R41481.
 Jeffrey W. Hornung, Managing the U.S.-Japan Alliance: An Examination of Structural Linkages in the Security Relationship (Washington, DC: Sasakawa USA, 2019), 32-33, https://spfusa.org/wp-content/uploads/2019/12/Managing-the-Alliance_v2-FINAL.pdf.
 Hornung, 33-34, 44-48.
 Japan Ministry of Defense, National Defense Strategy [Provisional Translation], December 16, 2022, 30, https://www.mod.go.jp/j/policy/agenda/guideline/strategy/pdf/strategy_en.pdf; “Japan to set up new joint command to manage SDF operations: report,” Japan Times, October 29, 2022, https://www.japantimes.co.jp/news/2022/10/29/national/sdf-joint-command-force/.
 “US mulls creating unified military command for Japan, looks to greater integration with SDF,” The Mainichi, January 6, 2023, https://mainichi.jp/english/articles/20230106/p2a/00m/0na/015000c.
 U.S. Congress, Senate, National Defense Authorization Act for Fiscal Year 2024, S 2226, 118th Cong., 1st sess., passed by Senate July 27, 2023, https://www.congress.gov/bill/118th-congress/senate-bill/2226/text; Ryo Nakamura, “U.S. weighs new military element in Japan for closer coordination,” Nikkei Asia, August 5, 2023, https://asia.nikkei.com/Politics/International-relations/Indo-Pacific/U.S.-weighs-new-military-element-in-Japan-for-closer-coordination.
 CRS, U.S.-South Korea Relations, 26-27.
 Drea et al., 69.
 Ibid., 1-6.
 “Organizational Interests,” in Morton H. Halperin and Priscilla A. Clapp, Bureaucratic Politics and Foreign Policy, 2nd ed. (Washington, DC: Brookings Institution Press, 2006), 25-61.
 Shin, 76.
 Indeed, Japan’s 2013 National Security Strategy declared the ROK as “a neighboring country of the utmost geopolitical importance for the security of Japan.” See National Security Strategy [Provisional Translation], December 17, 2013, 23, https://www.cas.go.jp/jp/siryou/131217anzenhoshou/nss-e.pdf.