Last month, the Japanese government released three landmark strategic documents: the National Security Strategy, the National Defense Strategy, and the Defense Buildup Plan. Collectively, they represent pathbreaking change and may signal that Tokyo not only shares a common strategic vision with the United States but is also committed to do far more for its own defense.
Japan’s post–World War II defense policy has been defined by incrementalism and inelasticity. Beginning in the 1970s, Tokyo had a tendency to constrain defense spending to 1 percent of GDP. After the country’s economic bubble burst in the mid-1990s, Japanese economic growth slowed significantly — and Japanese defense spending effectively stagnated as a result. Spending in 2021 was just 9 percent higher than the level almost 25 years earlier. Tokyo’s announcements on December 16 therefore signify an inflection point, both in the volume of planned defense investments and the capabilities the country intends to acquire. Together, these changes reflect an evolved concept of deterrence for Japan and what is required to sustain it, and once implemented they could result in a much more capable U.S. ally and critical force multiplier.
With complaints in Washington throughout most of the post–Cold War era that Japan’s security contributions were not commensurate with its economic stature, this newfound demonstration of commitment represents a significant step forward for Japan. If it follows through on its plans, Japan could emerge as a formidable defense actor over the next 10 years. All of this is good news for the U.S.-Japan alliance, given the increasingly important role Japan plays in Washington’s national security and defense strategies. Yet, even with a significant growth in spending — a planned nearly 60 percent increase in the defense budget over five years — clear prioritization will be critical to ensuring resources are used effectively and not spread thin across competing areas of focus.
Japan’s new defense approach and the resources behind it are positive for the region, the U.S.-Japan alliance, and Japan itself. At the same time, it is important to anticipate the challenges and impediments that could slow or alter implementation. As an ally at the center of much that the United States hopes to achieve in the region, it matters for policymakers in Washington that Japan succeeds. With this in mind, we focus on four major areas where Japan may encounter challenges in implementing its strategy in the years ahead: standoff defense capabilities, cyber capabilities, uncrewed capabilities, and — most importantly — manpower.
Japan’s New Approach
Describing Japan’s security environment as “the most severe and complex … since the end of World War II,” Tokyo’s national security and defense strategies set out plans for unprecedented change. First, Japan will increase annual defense spending by almost 60 percent by 2027, shattering the longstanding unofficial barrier of about 1 percent of GDP. The Defense Ministry’s budget request for Fiscal Year 2023, the first year of the plan, reflects an increase of more than 20 percent over the current year — which by itself would represent historic change. Second, it will acquire capabilities it has long eschewed, in particular long-range precision strike land attack missiles, capable of hitting targets deep inside North Korean or Chinese territory. While the Japanese government insists that the new strategies are consistent with the Constitution and post-war defense strategy, they nevertheless reflect an important evolution in Japan’s approach to defense and deterrence that traditionally focused on striking forces engaged in an armed attack against Japan itself. Today, while Japan’s strategy is still anchored on its defense, its deterrent focus is extended far beyond Japanese territory to striking those facilities that could support an attack against Japan. The reasoning behind this is the acknowledgement by Japanese decision-makers that simply relying on air and missile defense capabilities alone will prove insufficient should an adversary seek to attack or invade Japan. Counterstrike would give Japan the ability to target military facilities deep in an adversary’s territory, reinforcing deterrence by raising the cost of aggression against Japan.
The defense strategy sets out seven broad areas of focus for the defense buildup: standoff capabilities, including long-range precision strike; integrated air and missile defense; uncrewed systems; cross-domain capabilities, including space, cyber, and electromagnetic capabilities; mobility and lift; intelligence and resilient command and control; and a catchall “sustainability” category, which includes areas ranging from munitions stocks, to readiness and maintenance, to hardening of facilities. If done right, Japan could field a formidable force over the next decade that could play a credible force-multiplier role for the U.S. military in the region. But this wide range of focus invites concern about implementation and prioritization, even in an environment of increased resources.
Standoff Defense Capabilities
The capability that has received the most attention has been Japan’s decision to acquire long-range counterstrike capabilities, and increased inventories of missiles it has already decided to procure. This decision could make strategic sense, given the rapid development of Chinese and North Korean missile capabilities that can threaten the entire Japanese archipelago. Japan’s integrated air and missile defense capabilities are robust, and will expand further under the new plan, but focusing solely on intercepting missiles over Japan is almost certainly inadequate. The prospect of a Japan capable of responding to a missile attack with strikes of its own would introduce a challenging new variable in the decision-making calculus of Pyongyang and Beijing, possibly forcing them to invest more in defenses.
The decision to acquire this capability is therefore significant, and by itself will consume considerable resources. Japan’s budget outline envisions spending 5 trillion yen (nearly $50 billion) through 2027 on standoff capabilities of various ranges, including investments in shorter range weapons previously committed to like the Joint Strike Missile and the Joint Air-to-Surface Standoff Missile-Extended Range, acquisition of Tomahawk Land Attack Missiles, enhancements to the indigenous Type-12 cruise missile, and development of indigenous hypersonic capabilities.
Two factors could determine the credibility of Japan’s plans for a suite of strike capabilities and are important to track in the years ahead. The first is quantity. Historically, Japanese investments in munitions have been low, and even the small budgets set aside for munitions were frequently the victim of cannibalization to fund other priorities. For Japan’s strike capabilities to be more than symbolic, a dedicated commitment to stockpiling and storage may be needed. The volume of resources set out in the five-year plan, which includes specific spending figures associated with each system — with the exception of Tomahawk cruise missiles, which has yet to be determined bilaterally — appears to reflect a recognition that well-stocked missile depots could be critical to credible deterrence, and the FY2023 budget request reflects a concerted focus on munitions stocks. Because the actual numbers procured and stockpiled will never be made public, the onus will fall on the government to resist the temptation to scale back its stated goals or cannibalize the funds dedicated to them.
A second factor for consideration is the kill chain architecture and the concept of operations for Japan’s counterstrike capability. In the near term, Tokyo and Washington plan to work to integrate Japan’s capabilities — in particular the Tomahawk — into the U.S. intelligence, surveillance and reconnaissance, targeting, and battle damage assessment architecture. This is a smart strategy, one that could reduce Japan’s cost and accelerate the timeline for bringing a Japanese capability online, which Japan hopes to do by 2026. But the National Defense Strategy leaves open the question of whether Japan will eventually seek to develop its own autonomous kill chain architecture. The Defense Buildup Plan notes the “necessity” of Japan strengthening space-based capabilities to observe and track targets on-land and at-sea “at a high frequency,” pointing to an interest, also reported in the Japanese media, in developing a robust indigenous satellite architecture to support counterstrike operations. An effort to develop a separate, indigenous architecture could represent a significant resource drain, one that does not appear to be accounted for in the five-year budget. And because the development of such a satellite constellation could come at considerable cost, the wisest strategy is one that involves an integrated architecture with the United States over the long term.
Japan’s documents place a heavy emphasis on strengthening cyber capabilities across multiple lines of effort. Planned initiatives include creating a revamped national incident response center, with broader authorities to set cybersecurity standards across the Japanese government and to promote public-private information sharing on cyber threats to critical infrastructure. The documents call for developing an “active defense” cyber capability, in which the government would have the ability to penetrate and disrupt the computer networks of an adversary. Japan’s National Defense Strategy calls for a significant expansion of the Self-Defense Forces’ cyberforce, from around 800 personnel today to about 4,000 by 2027 with the total force population performing cyber functions growing to 20,000, focused on strengthening cyber defense of critical networks.
The National Security Strategy and National Defense Strategy focus on strengthening cyber capacity comes amid U.S. government concerns about cybersecurity vulnerabilities in the Japanese government, but important questions remain to be answered. Growing the cyber force as envisioned could require highly skilled personnel, but with challenges in recruitment, the personnel goal may be hard to achieve. Also unclear is where the government’s active defense capability would be housed. Media reports indicate plans to expand the Self-Defense Forces’ mandate to include defense of some critical infrastructure in the private sector, as part of a new legal framework for cyber defense to be established by 2024. Regardless of where these activities are housed and how many personnel can be devoted to them, new legislation could be required related to advance these initiatives. Given the sensitivity of privacy issues in Japan, and issues relating to the government getting more engaged in cyberspace, progress on this issue could require substantial political capital.
The Defense Ministry’s plans are arguably ahead of the curve inside the government. Other ministries with a role in national security may need to step up as well. The overarching priority for the Japanese government should be to strengthen common network security standards and cybersecurity practices across the system. In this context, the stated plans to develop an “active defense” capability are a secondary priority.
Japan is set on increasing the numbers and types of uncrewed capabilities across its three Self-Defense Forces services over the next 10 years, to perform not just information gathering and surveillance, but other missions, including combat support. Japan also wants to integrate these efforts with AI, which means instead of relying primarily on remote human operators and vulnerable communication links to make decisions, it will depend — in part — on computers. This appears logical, given Japan faces a quantitatively larger adversary in China and Self-Defense Forces recruitment continues to lag. Uncrewed platforms address both challenges because such assets generally can provide more coverage and persistent presence than crewed platforms, and can offer more affordable, attritable options that Japan can procure in greater numbers. They also can help address sustainment issues given that uncrewed assets generally require smaller facilities and can be dispersed to more austere locations throughout the archipelago.
To date, despite some tentative steps into uncrewed platforms, such as the Global Hawk, Japan has not seriously pursued uncrewed options. Because of this, the plan to jump from three Global Hawks today to a wide range of uncrewed platforms that incorporate AI in 10 years appears ambitious.
One challenge could be cross platform/cross domain integration, both in terms of communication between these uncrewed systems across different domains as well as how these platforms are used together with legacy systems. Successful integration, and the ability for multiple platforms to cooperatively work together, is a reasonable goal, but doing so well in a highly disruptive combat environment may be challenging to achieve in 10 years. There are also questions regarding how Japan seeks to establish a reliable method to control these platforms. The areas where Japan may have the most interest in deploying these assets are far from Japan’s main islands, requiring them to operate in locations where map data may be poor, for example undersea, or reliant on satellites that may be inoperable due to adversary jamming. While Japan hopes to deploy a satellite constellation which could help address these concerns, current military communication satellites are chronically overburdened and fighting for bandwidth.
Another challenge may come with incorporating AI into these systems. AI is attractive because it holds the promise of enabling autonomy, automating tasks, and making quicker decisions than their crewed counterparts. Within the next decade, AI may be effective at performing certain tasks better than humans, such as image recognition and multi-tasking, but AI systems require data to function and many AI systems are trained using data in an uncontested, controlled environment that has been inputted by a human. Getting to a future where AI-enabled uncrewed platforms can work well in a heavily contested environment with rapidly changing variables may be further off than the documents suggest. Critically, given Japan’s longstanding limitations on the use of force and strict rules of engagement imposed on the Self-Defense Forces, it is difficult to imagine that it will be willing to rely on automation to make engagement decisions for using force. Even with nonlethal missions, in a country that historically has delegated decision-making up the line of command, decision-makers are unlikely to be comfortable with delegating military operations to computers.
None of this is to suggest that Japan’s push for uncrewed platforms and AI is wrong, as these could play critical roles in future military applications. It is instead to suggest that Japan’s plan may be highly optimistic. Integrating AI and uncrewed platforms into any military system may be more of a gradual shift rather than one achievable in less than a decade.
The Overarching Challenge: Manpower
Of all the challenges that Japan will face, limitations in manpower may be its greatest. Japan is poised to undertake an unprecedented defense buildup — but it intends to do so without increasing the size of the Self-Defense Forces. Instead, there will be some reallocation of personnel across services — around 2,000 from the Ground Self-Defense Force to the Maritime Self-Defense Force and Air Self-Defense Force — but no growth in the overall size of the force. The reality of Japan’s shrinking population, and the traditional challenges meeting recruitment targets, could make any real growth impossible. In addition to introducing uncrewed assets, the strategy could rely on several personnel approaches — raising the retirement age of personnel, improving conditions for women, leveraging retired personnel for training and personnel development, and contracting and outsourcing. These steps make sense, given the manpower limitations, but the effectiveness of these solutions is open to debate.
Consider first raising the retirement ages and leveraging retired personnel. As a 2020 RAND report argued, these options age the force, which adversely affects Japan’s ability to support a regional contingency because older personnel face greater health issues and are likely less adept at incorporating new technologies than their younger counterparts. Contracting and outsourcing to private companies works in peacetime where the Self-Defense Forces can use transportation services by ships or planes to conduct drills or emergency responses for natural disasters, but it is unclear how realistic using civilian capabilities in a combat situation will be. And even if the push to introduce uncrewed capabilities is considered as a partial solution to the manpower issue, these too require personnel. In fact, given the nature of these platforms and the incorporation of AI, Japan may require more highly trained personnel than those currently recruited to operate legacy systems.
In combination with other elements of the strategy — including growing the cyber force, training operators for uncrewed platforms, introducing crewed ships focused on ballistic missile defense, and establishing a permanent joint operational headquarters distinct from the existing Joint Staff — finding sufficient personnel may prove to be a significant hurdle in achieving the objectives of the strategy. For example, compared with manpower shortages in a Ground Self-Defense Force infantry unit, where taskings can be shifted to other units, manpower shortages in the Maritime Self-Defense Force and Air Self-Defense Force could translate into deployment problems for ships and planes where those assets require a set number of personnel. Although the National Defense Strategy demonstrates a recognition of the manpower problem, it is unclear how effective the proposed solutions will be for developing the more robust and deterrent force the documents envision. If they fall short, implementing the strategy could become difficult.
Japan’s new strategic documents appear to demonstrate a recognition in Tokyo that it must do more for its own defense in the face of unprecedented security challenges. The dedication of resources, pursuit of new capabilities, and overarching commitment to a more robust defense are all significant moves that represent landmark change by one of America’s key allies — indeed, one of the most consequential strategic developments in the region in years. As positive as this appears, there is a risk that some ambitions may not be realized — at least on the timeline set out in the documents — due to insufficient resources, manpower, technology, or political will.
As a key ally, it is in the interest of the United States to help Japan address these challenges. The United States can help Japan where possible, through technology support, sales of key equipment, concept and doctrine development, or more realistic training. It could also work with Japan to help prioritize its efforts to avoid spreading finite resources too thin across all initiatives. Taking these steps now will help ensure that in 10 years the United States finds a more robust defense ally in Japan.
Jeffrey W. Hornung is a senior political scientist at the RAND Corporation and adjunct professor at Georgetown University.
Christopher B. Johnstone is Japan chair and a senior adviser at the Center for Strategic and International Studies. He served on the staff of the National Security Council during the Biden and Obama administrations, and in the Office of the Secretary of Defense for more than a decade.
Image: U.S. Navy photo by Daniel Barker