Japanese Prime Minister Fumio Kishida’s meeting with U.S. President Joe Biden on January 13 will provide a crucial opportunity to turn the page on decades of history in Japan’s security relationship with the United States. In mid-December, Kishida announced a new national security and defense strategy that departs from the path Japan has followed since World War II. The plan calls for Japan to increase defense spending by nearly 60 percent over five years, shattering the informal cap of one percent of GDP that has been in place since the 1970s. Japan will also acquire military capabilities it has long foresworn—in particular “counterstrike” missiles, or long-range precision weapons that will be mounted on vehicles, aircraft, ships, and eventually submarines. These will likely include U.S. Tomahawk land attack missiles, which Washington is preparing to sell to Tokyo. Japan will also heavily invest in cyber-capabilities, unmanned systems, and satellites that can support counterstrike operations. Tokyo has signaled that it intends to move quickly: Just a week later, the Kishida government unveiled a 6.8 trillion yen (about $51 billion) defense budget request for the next fiscal year, a 25 percent increase over the current year.

Once implemented, Japan’s strategy will transform the country’s place in the international security order. The prospect of a better-armed and equipped Japan will complicate North Korea and China’s calculations. But to maximize the effectiveness of Japan’s new posture, the country’s alliance with the United States must evolve. Today it is strong, but it falls short of a true military partnership capable of mounting integrated operations at short notice. As Japan pursues its new vision, the two close allies need a new command and control architecture, far deeper levels of information-sharing, and expanded cooperation between their defense industries. It is also time to revisit the cost-sharing arrangement that has long supported the U.S. military presence in Japan.

From Self-Defense to Active Defense

To create a stronger alliance, Washington and Tokyo must rethink alliance command and control. Japan’s new defense strategy calls for a significant expansion in bilateral military operations, including larger and more complex joint exercises with U.S. forces, enhanced joint patrols and reconnaissance operations, and deeper cooperation in the space and cyber-domains.

Japan’s development of a counterstrike capability in particular will require the two countries to work much more closely together. At least at first, and perhaps over the long term, Japan will need to rely on U.S. intelligence, targeting, and damage assessment capabilities to respond to an attack with strikes of its own. Japan does not possess those capabilities today. Any scenario in which it is launching long-range strikes against targets in North Korea or China —or even “active defense” cyber-operations, which penetrate and disrupt an adversary’s computer networks—would almost certainly coincide with military actions taken by the United States, underscoring the need for tight coordination based on a common understanding of the threat. Washington and Tokyo will need a dynamic ability to identify priority targets, determine who will mount the attacks and how, and assess the damage inflicted and whether further action is required. For the first time, the United States and Japan will need to be able to coordinate the use of force against targets outside Japan.

But unlike the U.S. alliance with South Korea , the U.S.-Japanese alliance was never designed to enable integrated military operations. When the alliance was created, Japan was essentially a platform for projecting U.S. power, a staging area for U.S. operations elsewhere in the region. This arrangement derived from Japan’s postwar constitution and the attendant policy restrictions on Japanese military activity. In the early days of the Cold War, Japan was never intended to become an important military partner for the United States. Japan’s Self-Defense Forces (SDF) and U.S. forces in Japan therefore built parallel and separate command structures, an arrangement that remains in place today—even as Japan has gradually expanded and strengthened the SDF’s roles, missions, and capabilities over the last two decades.

The policies and legal reforms of Shinzo Abe , the late former prime minister, led to much deeper cooperation between the U.S. and Japanese militaries and expanded the support Japan can provide to the United States in a contingency. The U.S. Navy and the Maritime SDF in particular have long maintained a close relationship that includes deep cooperation in antisubmarine warfare and ballistic missile defense. But the alliance’s command structure is still that of a bygone era and is insufficient to support the far more active defense role that Tokyo is now embracing.

As Japan follows through on its new defense strategy, these existing arrangements must change. Among other structural reforms of the SDF, Japan intends to establish a permanent joint operational headquarters modeled on a U.S. combatant command to exercise unified command of SDF operations. This new headquarters, long discussed and long overdue, will need a U.S. counterpart in Japan and a standing mechanism for planning and executing integrated military operations. No such U.S. counterpart exists in Japan today. Although the United States has a joint operational commander for its forces in South Korea, there is no equivalent in Japan; each U.S. service there reports separately to its respective component under the U.S. Indo-Pacific Command in Hawaii.

A more integrated structure will be essential to employing Japan’s new capabilities effectively.

The need for a joint U.S. operational command in Japan has been clear for some time. Indeed, such a command would have facilitated a smoother U.S. response and better coordination with Japan in the early days following the devastating earthquake and tsunami that struck in 2011. But with Japan now prepared to take on new military responsibilities and become a much more capable ally, the need for change is urgent. Establishing a joint U.S. operational command in Japan and a new bilateral architecture to coordinate integrated military operations is the critical next step in strengthening the alliance. This new architecture will ultimately need a planning cell directly connected to the Combined Forces Command in South Korea. This would allow coordination with American and South Korean forces in a crisis to ensure that Japanese military operations are synchronized with operations on the Korean Peninsula.

There are numerous models that Washington and Tokyo could adapt for enhancing joint command and control in Japan. The South Korean model—a combined structure in which the U.S. commander has authority over U.S. and Korean forces in wartime—is probably not politically tenable in Japan today, since there is no legal basis for SDF personnel to serve under a U.S. command. But a more integrated structure will be essential to employing Japan’s new capabilities effectively and in close coordination with the United States.

Two Eyes in Tokyo

Washington will also need to share more information with Tokyo to fully leverage Japan’s planned investments in defense, intelligence, and cyber-capabilities. Tactically, a credible Japanese counterstrike or cyberdefense capability will depend on a common real-time operational picture that integrates information collected by both countries. Strategically, a shared understanding of threats assembled from the full range of intelligence, including information gathered by spies on the ground, will also ensure that Washington and Tokyo’s approaches to the major challenges of the day are consistent. Information cannot be shared in one direction only; the United States must also benefit from Japan’s plans to strengthen its collection of intelligence gleaned from humans, signals, imagery and open sources.

Deepening the sharing of information and intelligence will require trust. Japan has historically been plagued by lax information-security practices. Despite significant progress over the last decade, including passage of the Secrets Protection Act under Abe in 2013, the Japanese government still lacks common information classification standards, a robust system for vetting personnel, and rigorous cybersecurity protocols that apply to all sensitive government networks. These problems reinforce the widespread view in the U.S. government, frequently more perceived than real, that “Japan leaks.”

Japan’s new national security and defense strategies acknowledge these vulnerabilities and prescribe ways to address them. The national security strategy calls for the establishment of a revamped national cyber-incident response center that has the resources to monitor threats and the authority to set cyber-related policy across the government share more information with the private sector.

As Japan brings enhanced capabilities online, it should share information at a comparable level with the United States.

The United States should recognize the stake it has in Japan’s success. For 15 years, the two allies have maintained a dialogue on information security aimed at strengthening Japan’s defensive practices. This dialogue has yielded some progress, and in a few discrete areas such as space and cyber-operations, the United States and Japan have established clear goals and the protocols needed to achieve them. But Washington has yet to comprehensively explain the benefits that Japan and the alliance would accrue from steady improvements in Japanese practices.

The United States should therefore develop a clear roadmap for elevating Japan to the status of a “Five Eyes” partner, the highest level at which Washington shares information with key allies. Such an effort would not be the same as inviting Japan to join the Five Eyes partnership, as that is probably neither realistic—given the range of policy and intelligence areas in which the five countries cooperate—nor perhaps desirable from Japan’s point of view. But the roadmap should lead to Japan attaining an equivalent stature in information sharing—and trust. This roadmap should lay out clear and measurable standards in the physical, personnel, communications, and cyber-security areas. If Japan is able to meet these standards, the United States should commit to share information on threats in the Indo-Pacific that is equivalent to what it shares with its closest intelligence partners. Built into this roadmap should be reciprocity: the idea that as Japan brings enhanced capabilities online, it will share information at a comparable level with the United States.

A commitment to accord Japan “Five Eyes”-like status if it meets measurable standards will require leadership from the highest levels of the U.S. defense and intelligence communities. Left to its own devices, the U.S. bureaucracy will continue to move the goalposts on what is required for a deeper information-sharing relationship and Japan will see little incentive to take difficult steps.

More Industry, More Security

Tokyo’s new national security and defense strategies recognize the need to strengthen the Japanese defense industry. Historically, Japan has had a comparatively weak and uncompetitive defense industry, focused only on the small domestic market, that produced capabilities sufficient to support a tightly constrained concept of defense. Because Japan effectively banned arms exports after World War II, the industry limited itself to building high-cost boutique equipment for the SDF that was supplemented primarily by purchases from the United States. This situation finally began to change with a partial loosening of arms exports under Abe in 2014. Still, U.S.-Japanese collaboration on advanced capabilities has so far been limited to the development of a ballistic missile defense interceptor in the early 2000s. Japan’s new strategy calls for more subsidies and spending on R & D to support the defense industry, among other steps. The risk of wasteful spending is high if Japan fails to develop a competitive presence in the international defense marketplace that leverages economies of scale and the best technology available.

Deeper defense industrial cooperation is in the interest of both the United States and Japan. Japan’s technology base holds significant potential for collaboration in areas such as aerospace, autonomous systems, and artificial intelligence. More robust Japanese production capacity would also help diversify the supply chain of the United States and its allies for key defense items including munitions, a critical need that the war in Ukraine has served to highlight. Ultimately, Japan’s military buildup is unlikely to be sustainable without an equivalent strengthening of the country’s defense industry.

Getting there will not be easy. The Japanese government must adopt more flexible and transparent export rules, promote equity-sharing partnerships with foreign defense firms, and send a clear signal that international partnerships are a top priority in increasing competitiveness. A restructuring of the defense industry is likely to be necessary. There are no dedicated defense firms in Japan, and defense represents a small percentage of overall business for even the largest industrial players, such as Mitsubishi Heavy Industries. For its part, the United States should commit to loosening restrictions on sharing technology with Japan, in line with the Five Eyes roadmap. The U.S. government should actively encourage defense industry collaboration and re-energize existing forums for discussion of joint development opportunities. As a near-term step, the United States, Australia, and the United Kingdom should invite Japan to participate in discrete (non-submarine) elements of the 2021 AUKUS security pact, which will support Australia’s acquisition of nuclear submarines and promote cooperation on other advanced capabilities. Japan could participate in that forum’s advanced capabilities agenda, such as hypersonics and counterhypersonic capabilities—fields in which Japan is already undertaking its own development effort.

Shared Resources and Stronger Readiness

As Japan increases defense spending to new levels, it will be necessary to revisit the cost-sharing arrangements that have underpinned its alliance with the United States since the 1970s. Japan currently spends about $2 billion annually on supporting the U.S. military presence in Japan, footing a large portion of the utilities costs on U.S. bases, the salaries of Japanese nationals employed on them, and the construction of new facilities for the approximately 55,000 U.S. troops currently stationed in the country. This arrangement, like other aspects of the alliance, is rooted in another era, when Japan was not a significant military partner and the alliance was effectively a one-way arrangement.

Japan’s commitment to increase defense spending and to invest in new capabilities is among the most significant strategic developments in the Indo-Pacific in decades. It is in the national interest of the United States to see that it is sustained and that the U.S.-Japanese relationship is strengthened as a result. Continuing the existing framework for cost-sharing would undermine the vision of a more equal alliance and partnership.

The current cost-sharing arrangement will expire in 2027, and assuming that Japan follows through on its defense buildup, it should be the last such agreement in its existing form. The United States and Japan should develop a plan that redirects some of the resources Tokyo has long put into basic support for the United States presence—like covering heating bills—toward mutually agreed priorities that support a more operational alliance. These may include shared training facilities, munitions stocks and depots, and fixed infrastructure. Attempting to sustain the current arrangement even as Japan transforms its defense strategy will precipitate contentious negotiations that are in neither country’s interest. Japan’s new national security strategy signals that the country is emerging from the legacy of World War II . The alliance should, too.

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  • CHRISTOPHER JOHNSTONE is Japan Chair and a Senior Adviser at the Center for Strategic and International Studies. He served on the National Security Council as Director for East Asia in the Biden administration and Director for Japan and Oceanian Affairs in the Obama administration.
  • More By Christopher Johnstone