Japan and South Korea: Doomed to Mutual Distrust?

The Strategic US-Japan-Korea Triangle: Emerging Perils and Prospects for Cooperation


Developments over the past two decades have made the challenge of trilateral cooperation more difficult for the United States and its two Northeast Asian partners, Japan and South Korea. Washington should promote major initiatives to improve the three-way relationships.

Two Key Alliances

Northeast Asia at once ranks among the most dynamic and the most dangerous corners of the world. Its key economies—Japan, China, and the Republic of Korea—have, in the aggregate, increased their collective gross domestic product more than 130-fold over the past half century, and have more than doubled it even over the past decade. The respective militaries of the region have more than 3 million active-duty personnel under arms, not counting substantial forward-deployed US forces, and reserve forces of over 11 million. The region is home to three nuclear powers apart from the United States (Russia, China, and North Korea) and two other potential nuclear powers (Japan and South Korea). And the power-projection capabilities of the key nations, including missile forces, are growing rapidly more sophisticated as well.

Within the Northeast Asian region, the United States has, since the early 1950s, maintained important bilateral alliance relationships with both Japan and South Korea, formalized by major mutual security treaties. The functional roles of the two long-time allies of the United States within the overall national-security structure of the Pacific have been somewhat different historically: South Korea has been involved in front-line confrontation with North Korea across the armistice line near the thirty-eighth parallel, which has never been stabilized by a formal peace treaty. The deterrent role of US ground and air forces south of the demilitarized zone has been crucial to sustaining the peace against a North Korean regime that has remained remarkably assertive, as evidenced by the sinking of the South Korean naval corvette Cheonan (a South Korean naval warship) and the shelling of South Korea’s Yeonpyeong Island in recent years, despite its declining economic capabilities.

In Japan, by contrast, US forces have consistently served a less direct but nevertheless vital strategic-reserve function. Since the early 1970s Japan has hosted what is now the only US aircraft carrier battle group based outside the United States, as well as the only Marine Expeditionary Force deployed permanently abroad, one of only three remaining in the entire world. For major contingencies ranging from Desert Fox (1998) to Desert Storm (1991) and for civilian disasters ranging from Sumatra (2004) to Sendai (2011), US forces based in Japan have played critical global security roles, in addition to their defense functions in Japan’s volatile immediate vicinity.

Diverging National-Security Imperatives

Half a century ago, the security challenge confronting Japan, South Korea, and the United States collectively was relatively straightforward and centered on the imperative of deterring North Korea from a repeat of the Korean conflict of 1950–53. Even though the complex twentieth-century history of the Northeast Asian region left enduring bitterness between Korea and Japan, while differing political systems also complicated cooperation, the two nations faced an immediate and largely common security threat from North Korea that allowed them to forge a quiet “virtual alliance” coordinated by the United States. Three developments over the past 20 years have, however, caused their respective national-security imperatives to diverge to some degree, thus making the challenge of trilateral cooperation simultaneously both more important and also more difficult for the United States and its two Northeast Asian security partners.

One major new development has been the rise of China, and its deepening involvement in the Korean Peninsula. Until 1992 Seoul and Beijing had no diplomatic relations and bilateral trade between the two countries was minimal. Today, however, China is South Korea’s largest trading partner, taking 25% of the latter’s exports, compared to only 10% percent for the United States, its second-largest trading partner. China also is virtually the only benefactor of North Korea, and Chinese firms serve as major brokers in North Korea’s political-economic relations with the broader world, including even South Korea. China’s rising political, economic, and military strength, as well as its deep involvement in Korean affairs, both North and South, is becoming a significant indirect constraint on US–Japanese–South Korean trilateral ties, albeit more in the political-economic sphere than on direct security matters.

A second major new challenge to the US–Japan–South Korea security triangle concerns North Korea’s own transformation. The North is growing weaker and weaker economically, although as one of the world’s most repressive political regimes, it is staving off collapse. Despite its economic weakness, however, Pyongyang’s military technology is growing more sophisticated, making it a de facto nuclear power with considerable emerging power-projection capability beyond its shores. The North is becoming a significant threat to Japan as its Taepodong missiles develop, even as its economic weakness poses deepening future challenges for South Korea. A sudden North Korean collapse could lead to abrupt reunification, or at least the need for large-scale aid on the part of the South to kindred Koreans north of the DMZ. With respect to the nature of North Korea’s future challenge, the perspectives and incentives of South Korea and Japan are thus diverging.

A third important change in Northeast Asia concerns the economic relations of Japan and South Korea themselves. The transformation of the economic ties between the two has accelerated since the beginning of 2013. Japan and Korea are directly competitive in several important sectors, particularly in consumer-durable industries such as automobiles and electronics. Even as the first two arrows of Abenomics (monetary and fiscal expansion) begin to revive the Japanese economy, they simultaneously tend to depress Korea’s prospects, particularly through the indirect mechanism of exchange-rate shifts. As the yen becomes cheaper against the dollar and other major currencies due to Tokyo’s domestically oriented monetary expansion, won-based exports have lost competitiveness in third markets, deepening frustration in Seoul.

Three Major Initiatives

Stability in Japan-Korea relations, and cooperative trilateral ties among Japan, South Korea, and the United States, are clearly important for Washington as China rises and the security challenge of North Korea deepens and broadens. Such trilateral cooperative ties are also very much in the strategic interest of America’s Northeast Asian security partners, whatever the political headwinds may be. In order to improve the trilateral relationships, three major initiatives are urgently needed.

First of all, the United States should strongly encourage the expanded involvement of both Japan and South Korea in broader multilateral security ventures, especially in the maritime sphere, building on the Defense Trilateral Talks that have been held annually since 2008. Trilateral search and rescue exercises, held most recently in October 2013, should be continued and intensified. Parallel Japan-Korea involvement should be expanded to other exercises as well, particularly those relating to maritime and air-defense contingencies, with US forces based in Japan included as appropriate. Multilateral exercises involving a broad range of nations, such as RIMPAC, could also be used as a context for Korea-Japan confidence building and coordination.

Secondly, additional areas for cooperative Japan-Korea overseas development assistance should be explored. Over the past half century, Japan has provided more than one-third of all the ODA that members of the Association of Southeast Asian Nations have received, and it continues to be the top net donor to the four ASEAN member nations—Cambodia, Laos, Myanmar, and Vietnam—that continue to receive major assistance. Korean aid is also substantial in Southeast Asia, so well-chosen, noncompetitive aid projects could enhance mutual cooperation, either on a multilateral or a bilateral basis. Public-goods sectors such as infrastructure, where risk is high and where benefits flow to a broad range of private firms, could be a good place to start.

Finally, the US-Japan-Korea trilateral defense dialogue should be invigorated. Priority areas could include missile defense, especially relative to emerging North Korean threats, and maritime security. The defense dialogue should be supplemented by trilateral discussions on related diplomatic issues, especially regarding the Middle East and Southeast Asia, as well as the East and South China Seas. Freedom of navigation, and opposition to arbitrary and sudden declarations of new air defense identification zones (ADIZs) are also issues on which the three countries share common concerns and prescriptions.

History, of course, hangs as a dark shadow over the US-Japan-Korea triangle, especially its Japan-Korea leg. The issue clearly must be actively managed to neutralize potentially adverse consequences for trilateral cooperation. That does not, however, suggest the advisability of any formal US mediation, since such formal US involvement would subject Washington to powerful cross-pressures from Tokyo and Seoul that could damage either or both of its important Northeast Asian bilateral alliances. That said, quiet official encouragement from Washington for deeper Japan-Korea relations, coupled with “track two” (citizen diplomacy) initiatives involving knowledgeable former US policymakers, could be very much in order, together with third-party track two initiatives from friendly allied nations like Canada, Germany, and Australia, or possibly from ASEAN. Given the delicacy of current Japan-Korea economic ties, provocative gestures in the history arena—either in Japan or in Korea—could have especially damaging effects, and need to be avoided.

In the final analysis, Japan, Korea, and the United States share important security concerns, intensified by the rise of China and continuing uncertainties in North Korea. America’s two Northeast Asian allies do, to be sure, also have some increasingly divergent security incentives, particularly with regard to the nature and intensity of the North Korean threat. As Pyongyang’s power-projection capabilities continue to rise, they become an increasing concern for the United States as well. Washington has every reason to press for expanded trilateral cooperation, and the time to press forward with that agenda is now.

(Originally written in English on December 4, 2013. Title photo: US Secretary of Defense Chuck Hagel poses with Japanese Defense Minister Onodera Itsunori (left) and South Korean Defense Minister Kim Kwan-jin (right) before their trilateral meeting in Singapore on June 1, 2013. [Wong Maye-E/AP Photo/Aflo])

United States security North Korea South Korea Abenomics