To restrain Japan, South Korea should embrace greater security partnership

By Lee Jong-eun

Despite being allies of the United States, South Korea and Japan did not have a direct security partnership during the Cold War. During the Korean War, South Korean President Syngman Rhee threatened to shoot Japanese forces first if they arrived to "help" Korea from the communist invasion. Japan, officially a pacifist state with "self-defense forces," also did not affirm its security commitment to the neighboring democracy. The two countries' animosities over past history and their reliance solely on U.S. security commitment were factors that limited bilateral security partnerships for decades.

More recently, growing geopolitical tensions with China and North Korea have motivated South Korea and Japan to improve bilateral and trilateral partnerships with the U.S., such as the signing of the Trilateral Information Sharing Arrangement (TISA) and General Security of Military Intelligence Agreement (GSOMIA) to enhance collective responses to North Korean missile tests. This year, South Korea's President Yoon Suk-yeol and Japan's Prime Minister Fumio Kishida have made several overtures to reset past several years of difficult bilateral relations during their predecessors.

In September and October, the ROK (Republic of Korea or South Korea) and Japan's navy conducted trilateral military exercises with the U.S. navy in the East Sea. In November, Yoon and Kishida met with U.S. President Biden in Phenom Penh, Cambodia, before the start of the G20 Summit and announced a trilateral statement. The statement affirmed cooperation on strengthening extended deterrence, real-time intelligence sharing on North Korea's nuclear and missile threats, and consultations on safeguarding "economic security" from geopolitical challenges with China.

Enhancing the ROK-Japan security partnerships, however, continues to face major obstacles. One major obstacle is the unresolved disputes over history, such as the reparations for Korean comfort women and forced workers by the Japanese government and companies. Another major obstacle is South Korean domestic politics' continued distrust of Japan's military capacity and intention.

During the trilateral naval exercises in October, South Korean opposition party leader Lee Jae-myung warned that Japanese naval operations in the East Sea threatened South Korea's sovereignty over the Dokdo Islets. This month, with Japan's announcement of a new national security strategy, the South Korean press has expressed concerns that Japan's boost in military spending and acquiring of counterstrike capacity against North Korean missile threats will endanger the security of the Korean Peninsula.

South Korea's security reservations toward Japan reflect a common strategic dilemma of a state weighing the risks of entrapment and isolation from a potential security partner. For South Korea, while there are security benefits in aligning closer with Japan and the U.S. to bolster deterrence against North Korea and China, there are also risks that Japan's aggressive security responses could escalate geopolitical conflicts.

In the future, will Japan engage in counterstrikes against North Korea's missile bases without consultation with South Korea? With increased defense spending, will Japanese naval forces confront the Chinese navy more frequently over the disputed Senkaku Islands? Directly bordering North Korea and maintaining close economic ties with China, South Korea is concerned that Japan's military expansion creates additional uncertainty in regional geopolitics.

Looking ahead to the future, South Korea, however, should consider the likelihood that Japan's military expansion will continue. The occurrences of the Russia-Ukraine War, China's military exercises near Taiwan, and North Korea's more than 60 missile tests this year have shifted Japan's domestic politics in favor of greater defense capability.

The Biden administration has also approved Japan's new national security strategy as strengthening the U.S.-Japan alliance. With North Korea and China condemning Japan's "militarization," South Korea faces a strategic decision on whether to distance itself from Japan's security strategy or to collaborate.

While there are proponents for South Korea's "deliberative hedging" in the growing strategic divide between the U.S.-Japan and China-North Korea alliances, I recommend that South Korea engage Japan in greater security partnership to mitigate the risks of security entrapment. To deter Japan and even the U.S. from militant measures that impact South Korea's security adversely, the trilateral security framework should become more institutionalized so South Korea has greater access to institutional mechanisms for coordinating common security responses with the other two countries.

For South Koreans concerned with Japan's pursuit of counterstrike capability against North Korea, the effective response is to establish protocols for coordinating counterstrike measures, to ensure Japan is deterred from taking military actions without consultations and consensus from the U.S. and South Korea.

For South Korea, expanding its security partnership with Japan risks antagonizing China and North Korea. However, an even greater security threat will be if the Japan-U.S. alliance implements security measures independently from South Korea that further escalate regional tensions. For example, how will South Korea be impacted if Japan persuades the U.S. to approve relaxing the Three Non-Nuclear Principles (Not possessing, producing, or deploying nuclear weapons in Japan)?

The purpose of an alliance is not simply to deter threats from enemies but also to ensure that one's allies are restrained from causing risky consequences. The U.S. also established bilateral alliances with South Korea, Japan and Taiwan in the early days of the Cold War to restrain the potential militant behaviors of its Asian allies. While there is a phrase, "Keep your friends close, and keep your enemies closer," a more applicable version for the ROK-Japan relationship might be "keep your worrisome friends even closer."

Finally, South Korea should demonstrate its contributions to the security partnership. How can South Korea contribute to addressing Japan's security concerns? For South Korea to restrain Japan from making security decisions affecting Korea without Korea's consent, it is important also to communicate to Japan that its security interests can be advanced more effectively together with South Korea.

And perhaps, building such mutual security trust will be constructive progress toward resolving the other major obstacle in the ROK-Japan relationship over their historical past.

Lee Jong-eun (jl4375a@student.american.edu), a Ph.D. candidate, is an adjunct faculty member at the American University School of International Service. Previously, he served as a Republic of Korea Air Force intelligence officer. His research specialties include U.S. foreign policy, South Korean politics and foreign policy, alliance management and East Asian regional security. The views expressed in the above column are those of the author's and do not reflect the editorial direction of The Korea Times.