Friends, Whether They Like It or Not: U.S.-ROK-Japan

Leaders of the U.S., South Korea (ROK), and Japan met in the middle of November 2022 to reaffirm their trilateral partnership to combat the nuclear threat from North Korea and align their collective efforts in pursuit of a free and open Indo-Pacific (FOIP). The statements indicate a hopeful future for deeper and more comprehensive cooperation between the three countries, and particularly for Japan and South Korea. For decades, Japanese and South Korean national security has been inextricably linked by common threats, and their alliance with the U.S. But lingering historical animosities between Seoul and Tokyo have made cooperation between Japan and the ROK uneasy, and issues such as the Japanese wartime labor dispute continue to weaken cooperation between the two U.S. allies.

Japan’s proximity to three out of four geopolitical adversaries to the U.S. (China, North Korea, and Russia; the fourth being Iran) has made Japan indispensable to U.S. security strategy in the region. Japanese and South Korean interoperability as well as the U.S. base structure in Japan is especially important for the U.S. to maintain not only security commitments to Japan, but also the ROK in the event of a crisis. At the outset of the Korean War, the United States had about 500 advisers stationed in South Korea but owing to a sizable American military presence in Japan following World War II, the U.S. was able to respond to the North Korean invasion considerably more quickly than any other State.

The unrestricted use of military bases in Japan has since then been essential to U.S. and ROK readiness in the event of a crisis on the peninsula. Any restrictions against the use of Japanese bases during a crisis would change the U.S.’s entire strategic defensive position and would place severe limitations on the value of Japanese bases from an American perspective.

Current Security Arrangement

The Treaty of Mutual Cooperation and Security (Japan-U.S. Security Treaty) between the United States and Japan was signed in 1960 and committed the U.S. to defend Japan in the event of an attack and required consultation with the Japanese government before dispatching any U.S. forces based overseas. Compared to the Security Treaty between the United States and Japan signed after World War II, the Japan-U.S. Security Treaty doesn’t allow for the U.S. to station military forces in Japan and to send them overseas without prior consultation. In order to streamline the U.S.’ ability to uphold its security obligations to the ROK, a series of open as well as secret agreements have been made between the governments of Japan and the U.S. The secret Korean minute and the open Korea clause are the two agreements allowing the U.S. to deploy troops to defend the ROK in the advent of a crisis on the Korean peninsula.

The Korea clause refers to the acknowledgment by the Japanese government that Korean security is also a matter of Japanese security and that the Japanese government vows to assist the U.S. in defending the ROK in the event of a renewed conflict. The Korean minute on the other hand refers to the secret agreement between the Japanese government and the U.S. to allow for the immediate troop deployment of U.S. forces to the Korean peninsula without prior consultation with the Japanese government.

Both the Korean minute and the Korea clause are a result of U.S. strategic thinking and constitute part of a concerted effort by the U.S. in which the authority of the United Nations was used to legally justify its continued presence in the ROK and Japan. In particular, the two agreements are closely connected with the United Nations Command (UNC), which constitutes the U.S.’s primary framework for security cooperation between the ROK and Japan.

Role of the UNC-rear

The UNC was established in 1950 as a multinational military force established to support the ROK during and after the Korean War. The United Nations Command-Rear (UNC-rear) was established in 1957 as a result of the UNC’s relocation from Japan to the ROK following the Korean War. Its primary function is to uphold the Status of Forces Agreement (SOFA) between the UN forces (under the command of the U.S.) and Japan since the UN-GOJ SOFA agreement (United Nations-Government of Japan Status of Forces Agreement) required UN command to maintain a presence in Japan as a precaution for continued use of Japanese territory for military purposes, particularly in the defense of the ROK (Article XXV of the UN-GOJ SOFA).

U.S. procedure to facilitate cooperation with its allies is well established and continues to be the anchor for U.S.-ROK-Japanese cooperation. But security links between ROK and Japan are much less developed and rely primarily on U.S. coordination through the UNC. And the few security agreements that Japan and the ROK have, such as the Intelligence sharing agreement GSOMIA (General Security of Military Information Agreement) which was almost scrapped because of lingering ROK-Japan disputes and culminated in a trade dispute between the two countries. Only after pressure from the U.S. did the ROK suspend its plans to withdraw from the agreement.  

If the GSOMIA mechanisms had been dissolved, Japan and the ROK could still share classified information with each other through the Trilateral Information Sharing Agreement with the U.S. but doing so would be far less streamlined. In the event of a crisis on the Korean peninsula, it is probable that the ROK and Japan would cooperate, but it is likely to be incoherent and insufficient compared to standardized procedures and mechanisms for cooperation between all three countries.

Japan-Korea Relations

The recent trilateral meeting between Prime Minister Kishida, President Yoon, and President Biden caused a lot of headlines. But the statement presented no concrete plans to further interoperability apart from reaffirming U.S. security obligations and vowing to strengthen deterrence and continue to share real-time DPRK missile warning data. Japanese-Korean relations remain frosty and aspiring rhetoric rarely manages to address the underlying issues that have prevented Japan and the ROK from reconciling and fully committing as security partners.

Fundamental issues such as the Takeshima/Dokdo dispute, the comfort women issue and the Sea of Japan naming dispute threatens to undermine U.S.-ROK-Japanese attempts at developing deep and long-lasting cooperation, particularly between Japan and the ROK. And recently, the forced labor dispute has threatened to undo several years of efforts to try and improve Japanese and Korean relations. In August, the Suwon District Court approved the seizure of assets of Mitsubishi Heavy Industries to restitute victims of forced labor by Japanese firms during the colonization of Korea. Japan asserts that this is a clear violation of State immunity and that it is unacceptable for the government of Japan to be subject to the jurisdiction of the ROK.

Furthermore, Japan considers most Japanese-Korean disputes to have been resolved in the 1965 treaty on Basic Relations Between Japan and the Republic of Korea—any issues concerning property and claims between Japan and the ROK, including the issue of comfort women, was “settled completely and finally” (Article 2). Korea on the other hand claims that the 1965 treaty was signed under less-than-ideal circumstances and by the then military dictator of Korea, Park Chung-hee, a former member of the Manchukuo Imperial Army. Korea claims that Japan never seems to realize what it has done and refuses to make a sincere effort to try and reconcile for its actions during the colonial period. As such, the ROK withdrew from the 2015 comfort women settlement between Japan and the ROK claiming that Japan had undermined the spirit of the agreement.

Recent efforts to try and resolve the forced labor dispute have included having a third party provide compensation to the victims, but it remains to be seen if such an agreement can be reached or if it can satisfy public opinion on the matter.

Implications for Japan

Japan’s status as one of the few countries in East Asia that can go toe-to-toe with China has allowed Japan to present itself as a bulwark against China’s increasing assertiveness in East Asia. One of late Japanese Prime Minister Shinzo Abe’s political ambitions was always for Japan to adopt a much bigger role in East Asian security. The Quadrilateral Security Dialogue (Quad) and the FOIP strategy are two initiatives helmed by the Japanese government that falls in line with Washington’s strategy to uphold the status quo in East Asia. Japan’s centrality in all these initiatives is further exacerbated by Japan’s role as the lynchpin for America’s security structure in Asia. Any possibility for the U.S. to assist the ROK or Taiwan in a crisis is premised on U.S. base structure in Japan.

While both Japan and the ROK have been forced to cooperate because of common threats from North Korea, Japan’s security concerns reach much further than just the Korean Peninsula. Meanwhile, the ROK continues to balance its relations with its treaty ally and main security guarantor, the United States, and its biggest trading partner and crucial North–South dialogue partner, China. This has made the ROK’s attractiveness as a preferred strategic partner in the Quad much less appealing and the lingering security dilemmas between Japan and the ROK could possibly detract from the Quad’s efficiency and hinder its rapid progress.

The U.S. want nothing more than for Japan and the ROK to cooperate and constitute a strong and united trilateral in Northeast Asia, but lingering tensions between Korea and Japan keep rearing its head, making such ambitions hard to realize.

Looking Forward

The lingering feelings of historical injustice and resentment over Japanese colonialism within Korea are so deeply rooted in the national identity that “anti-Japanism” is now a form of political correctness in the ROK, which public officials dare not bend, forcing ROK officials to tread very carefully when it comes to deepening cooperation between the two countries.

Similarly, the ROK’s tit-for-tat regarding Japan’s efforts to build a state of normalcy in their relations has brough about a widespread “Korea fatigue” among Japanese officials. This has led to Japan trying to structure its security policies in a manner that does not include the ROK. The Quad and FOIP reflect this as they indicate that China is a bigger concern to Japan than North Korea. Japan’s indispensable role in the U.S.’s containment strategy for China enables it to not necessarily accommodate the ROK but wait for the ROK to accommodate Japan. However, it can’t do that when it comes to North Korea and both the ROK and Japan need to develop deeper cooperation and interoperability before it is too late. Relying on the UNC and American coordination to build an effective deterrence is not enough.

While Japanese and South Korean issues won’t be solved anytime soon, the recent talks and agreements such as GSOMIA can hopefully ease tensions, and possibly change the perceptions of one another as reliant security partners. Whether Japan or the ROK like it or not, they both rely on one another to facilitate their own security strategy. Let’s hope that the two countries can develop the U.S.-ROK-Japan trilateral security structure into an equal partnership of cooperation, rather than a bifurcated partnership between the U.S. and Japan and the ROK.