Japan finds itself in a challenging and complex security environment, managing a variety of threats while only spending roughly one percent of gross domestic product on defense and further negative demographic projections. Spurred on by changing threats, namely North Korean nuclear and missile capabilities, along with China, Japan decided in 2017 to purchase Aegis Ashore, an American air defense system, with a projected cost of 5.2 billion dollars over 30 years. However, the program was abruptly canceled in June 2020 by Defense Minister Taro Kono, who has a reputation for individualism and has been called a maverick by the press. He cited the cost it would require to redesign the missile booster such that it would not fall in residential areas. This cancellation has caused domestic political fallout, confusion at home and abroad, and generated risks along with strategic opportunities.
Aegis Ashore would have mitigated a significant portion of the threat presented by North Korean missiles, providing an additional but more permanent defensive layer, a cog of a larger defensive ecosystem. To that end, it would have intercepted missiles in the “midcourse” stage of flight, where a missile has already ascended into the atmosphere and begun to coast towards its target. As such, it had many supporters in Japanese society, from the ruling Liberal Democratic Party’s (LDP) Prime Minister Abe to others in defense circles which seek to develop Japan’s military capabilities.
Japan currently operates two systems to face ballistic missile threats: The Air Self Defense Force’s multiple batteries of PAC-3 Patriot missile systems and the Maritime Self Defense Force’s (JMSDF) seven destroyers armed with their own Aegis radars and missile interceptors. Both have their own shortfalls. Missile defense ships suffer from general naval realities, such as tasking for other assignments or mandatory in-port time for maintenance or refit, which prevent these ships from accomplishing a ballistic missile defense (BMD) mission. The PAC-3s suffer from the short range of their interceptors, more suitable for point defense work rather than the larger protective bubble Aegis systems provide.
Aegis Ashore itself consists of components found on many of the U.S. Navy’s warships, combining an air search radar, a Vertical Launching System (VLS), and SM-3 missile interceptors. These components are then installed on land, providing missile defense coverage through the resulting Aegis deckhouse and VLS magazine. However, Aegis Ashore is opposed by the local residents of at least two cities, Akita and Abu, primarily due to a fear of falling booster rockets (one stage of the SM-3 interceptor) and a fear of becoming a target for hostile powers. This pressure led at least one LDP member in the Akita Prefectural Assembly to openly oppose to the program, and could have been a factor in Minister Kono’s decision.
Unfortunately, there are not many system-to-system solutions that are currently available for Japan to mitigate the threats the program was designed to counter. One option, deploying another American missile defense system, known as Terminal High Altitude Area Defense (THAAD), is unfeasible for multiple reasons. One THAAD battery consists of an 800 million dollar system of launchers, interceptors, and radars, expensive to man and equip. Additionally, THAAD has a smaller range, requiring multiple sites to provide the same coverage as two Aegis Ashores, resulting in the same challenges in terms of boosters and cost that produced the program’s original cancelation. Another option, the purchase of additional Aegis warships, is also unfeasible. The JMSDF cannot man them, as the service already has personnel shortfalls and would be unable to recruit and train the 300 sailors required to operate the warship. Further, though Aegis warships fulfill a variety of missions, they cost more over time to operate than Aegis Ashore. Thus, Japan will experience, for the foreseeable future, a shortfall in defense capabilities and the risks associated with that.
Most opportunities available for Japan come from the shifting of resources from Aegis Ashore to other programs or initiatives. Recent reporting suggests that Minister Kono’s decision has triggered a reassessment of Japanese military budget priorities. None of the readily available options provide Japan the direct BMD capability it desires.
However, one promising path is a deepening of the U.S.-Japan alliance through the further joint funding and development of future technologies. There are ample programs to which resources could be allocated, from the Ministry of Defense’s specific desire for joint development on the F-3 next-generation fighter program to the numerous subsystems found on naval platforms. Both Japanese and U.S. defense white papers have highlighted the need for innovation in similar areas, and cooperation could flow naturally. The SM-3 Block IIA interceptor, used for BMD and with the Aegis combat system, is a result of joint development between U.S. and Japanese firms and a key example of the win-win nature of joint technological development between staunch allies, critical to the national security interests of both nations.
Further, Japan could earmark parts of the 5.2 billion dollars in other ways that synergize with U.S. capabilities and build capabilities in emerging domains. One option is labeling select JSDF facilities for “joint use” and paying for costs associated with that. In doing so, Japanese policymakers avoid the difficult domestic conversation of alliance burden sharing, while providing tangible value to U.S. forces. For example, a joint use facility could involve JSDF personnel maintaining common platforms, such as U.S. UH-60 Blackhawk helicopters or P-3 Orion patrol aircraft, or otherwise providing U.S. forces with enhanced capabilities. Additionally, Japan could increase its investments in cyber or space capabilities, as it has already shown an intent to accomplish. Increased or accelerated investments would reinforce Japan’s capacity in these domains and bolster the capabilities of the alliance to respond to common threats.
Finally, and most contentious, Japan could acquire “first-strike” precision-guided munitions from its European allies, through indigenous development, or, most likely, from the United States. Weapons such as the AGM-158 JASSM (Joint Air-to-Surface Standoff Missile) have the ability to travel in excess of 100 miles, with the JASSM-ER variant able to strike targets an astounding 600 miles away. This would give the JSDF the ability to strike missile sites inside of North Korea, for one, provided an attack on Japanese territory is imminent. Regardless of the course of action Japanese policymakers pursue, the difficult steps forward will be analyzed through a revision of the National Security Strategy (NSS), which has not changed since 2013 and is long overdue for review. The opportunities currently available to Japan do not provide the same feasible missile defense capability that Aegis Ashore does. From targeting enemy bases, to reinforcing and deepening the alliance, Japan will likely pursue Aegis alternatives to fill a perceived gap in security capabilities, but every choice brings different strategic outcomes. If Japanese policymakers desire to protect their homeland in the most robust way possible, a full review of all options, including Aegis Ashore, is required, preferably through the NSS. Ultimately, Japan has a wide range of opportunities, if only the political will exists to grasp them.