The Peninsula

Prime Minister Ishiba’s Asian NATO Proposal and Korea-Japan Defense Ties in Korean Peninsula Contingencies

Newly installed Japanese Prime Minister Ishiba Shigeru caused waves in October over comments he made before his election. In an article published by the Hudson Institute, he said that in light of Russia’s invasion of Ukraine, the lack of a mutual defense organization in the Indo-Pacific region increases the likelihood of conflict. “Under these circumstances, the creation of an Asian version of NATO is essential to deter China by its Western allies,” wrote then candidate Ishiba. The idea of a treaty-based security organization in the region is not new. The United States floated the idea of a Northeast Asia Treaty Organization in 1954, but it did not gain traction and gave way to the hub-and-spokes system. With greater trilateral security cooperation between the United States, Japan, and South Korea in recent years, the idea of an “Asian NATO” seems like a possibility. But enduring mistrust within South Korea toward Japan and Prime Minister Ishiba’s vague proposal make it difficult to expect an Asian NATO to appear in the near future.

South Korea’s Response to Ishiba’s Comment

While not a strident rejection, South Korea gave a cool response to the prime minister’s Asian NATO proposal. China’s Ministry of National Defense said Beijing “firmly opposes” the creation of such an organization. Spokesman Wu Qian accused Japan of violating its peace constitution and said that Japan should “do more things that are conducive to maintaining regional peace and stability.” In comparison, South Korea’s Minister of Foreign Affairs Cho Tae-yul said that it was too early to begin discussions on Seoul’s participation. During a hearing at the National Assembly, he described the idea of an Asian NATO as Japan’s strategy to deal with mid- and long-term regional security issues and stated that South Korea “will give thought to it.” The Korea Times was also skeptical in an editorial published after Prime Minister Ishiba took office. Along with his interest in revising the Japanese constitution, “these positions raise concerns about Ishiba’s inclination to support a resurgence of Japan’s military power,” the paper said.

Japan’s Role in a Contingency on the Korean Peninsula

Despite skepticism of Japan’s intentions, its capabilities have been and will be critical to resolving any contingency on the Korean Peninsula. During the Korean War, Japan played an important role in supporting Allied operations. Japan had critical minesweeping capabilities and participated, along with the United States and South Korea, in Operation Wonsan to remove North Korean mines supplied by China and the Soviet Union. Japan also served as a logistical hub for Allied personnel and equipment headed to the Korean Peninsula. This role continues today, with the Yokota Air Base hosting the rear headquarters of the United Nations Command (UNC). Six other bases in Japan can be used by UNC states in the event of a contingency on the Korean Peninsula: Camp Zama, Marine Corps Air Station Futenma, Kadena Air Base, Sasebo Naval Base, White Beach Naval Base, and Yokosuka Naval Base. Dr. Michael Bosack says that because of Japan’s efforts to play an active role in regional security issues, “the Japan-UNC relationship becomes ever-more relevant, both in existing functions and in new areas of cooperation vis-a-vis the North Korean threat.”

In addition to minesweeping and logistics, experts say Japan would also be expected to play a role in countering North Korean missiles. Earlier this month, the United States flew a B-1B bomber as part of trilateral aerial exercises with Japan and South Korea. The exercise follows last year’s announcement that the three states had successfully implemented a North Korean missile-warning information-sharing mechanism. At the 2023 Camp David Summit, the United States, Japan, and South Korea also released the Commitment to Consult, in which they vowed to “coordinate our responses to regional challenges, provocations, and threats affecting our collective interests and security.” In addition to these trilateral developments, Japan is working to develop its own defense capabilities. In mid-October, the US Defense Security Cooperation Agency announced that it had approved the sale of over 200 Rolling Airframe Missiles Block 2B, RIM-116E. These missiles would be deployed on Japanese ships to defend against anti-ship missiles. Previously, Japan announced that it would purchase up to 400 Tomahawk missiles from the United States for deployment on its Aegis destroyers. Given developments in Japan’s missile defense capabilities, Dr. Ju Hyung Kim recommends that Korea and Japan integrate them with South Korea’s ballistic missile defense systems.

Obstacles to Korea’s Involvement in an Asian NATO

Despite this, lingering distrust in South Korea may make it difficult for Seoul to join a treaty-based alliance with Tokyo. Kwon Hyuk-chul, an editor at the progressive Hankyoreh newspaper, says that it is unclear if Japan is an enemy or a friend of Korea. “When a person presents as an enemy right from the outset it is possible to keep your distance and remain vigilant,” he wrote. “But there are also times when someone you thought was a friend later turns out to be an enemy.” This suspicion of Japan is still held by other parts of Korean society. Earlier this summer, protesters in Seoul carried signs that said “Stop the push for South Korea-Japan military alliance” and “No to Japan Self-Defense Forces’ entrance to Korean Peninsula” during then Prime Minister Kishida Fumio’s visit before his resignation. “We cannot form an alliance with Japan, which constantly claims sovereignty over Dokdo,” said opposition politician Park Chan-dae. Despite President Yoon Suk-yeol’s efforts to repair relations with Japan and restart defense cooperation, this stumbling block remains.

Another important obstacle to realizing an Asian NATO is that the proposal is not well-defined. In his first appearance before the Diet after taking office, he admitted that his comment reflected his own personal beliefs and did not reflect a policy stance of his administration. An Asian NATO was also not on the agenda of his inaugural trip to Southeast Asia. “It is something I have had in mind for a long time,” he said at a press conference in Vientiane, Laos. “But it is my idea, and I expect discussions will take place within the LDP to make it more concrete.” The prime minister has directed members of his party to look into the feasibility of an Asian NATO, but this is still far from a concrete proposal. As Dr. Jeffery Hornung from the RAND Corporation observes, “Ishiba the campaigner may very well be different from Ishiba the prime minister.” The ruling Liberal Democratic Party’s shellacking in the recent Diet elections also calls into question the viability of the Ishiba administration itself.

What Comes Next

US, Japanese, and South Korean officials are clear that they will respond seriously in the event of a contingency on the Korean Peninsula. Whether that comes under the aegis of a treaty-based alliance—either bilateral between Seoul and Tokyo or multilateral like NATO—remains a distant dream. But there are things that can be done below that level that can still be helpful. Dr. Kim observes that with the formal institutionalization of trilateral coordination, policymakers from both sides should discuss now how their respective plans toward a Korean contingency interact to avoid having to deal with differences in the future. “It is crucial for the tripartite to work diligently to prevent this, as a division would leave them ill-prepared to handle a crisis in Taiwan, on the Korean Peninsula or both,” he writes. This should also extend to planners responsible for military exercises. While the United States, Japan, and South Korea have held exercises together, retired Vice Admiral of the Japan Maritime Self-Defense Force Yoda Koji says there are “no unit-level training programs being implemented” to deal with a contingency on the Korean Peninsula. “This will make ‘on-the-ground’ combined operations possible and will ensure the realization of the goal of more robust trilateral security cooperation,” he also says.

Another issue that Korean and Japanese defense officials should work on is building public support for bilateral security cooperation. On the one hand, it may seem improper for military officers to become involved in political discussions. On the other hand, domestic political currents could undermine the objective benefits wrought by security cooperation. In 2018, Dr. Bosack said that UNC-Rear periodically lets members of the South Korean military and national legislature tour UNC bases in Japan. “Those tours serve as reminders of Japan’s critical role in the event of any contingency on the peninsula,” he said, “which are vital in influencing decision-making that otherwise may seek to block cooperation with Japan for solely political reasons.” More recently, Vice Admiral Yoda pointed out that weakening support for US forward deployments should be a concern for Korean and Japanese policymakers as well. “Tokyo and Seoul not only need to work on promoting support in their own countries for cooperation with each other,” he said, “but also find ways to increase public support in the United States for American armed forces to continue playing an essential role in East Asian security affairs.” Whether under a formal treaty alliance or a bolstered bilateral partnership, Korea and Japan should build the foundations for security cooperation that is beneficial to both sides.

Terrence Matsuo is a Non-Resident Fellow at the Korea Economic Institute of America. The views expressed here are the author’s alone.

Photo from the Prime Minister’s Office of Japan.

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