Tokyo Report | Security | East Asia

The Critical 6 Months for US-Japan Defense Cooperation We Never Saw Coming

The remainder of 2020 is shaping up to be an unexpectedly consequential year for U.S.-Japan defense cooperation.

By James L. Schoff for
The Critical 6 Months for US-Japan Defense Cooperation We Never Saw Coming

Then-Defense Secretary James N. Mattis meets with then-Japanese Foreign Minister Taro Kono at the Pentagon in Washington, D.C., March 16, 2018.

Credit: DoD photo by U.S. Air Force photo by Tech Sgt. Vernon Young Jr.

Policymakers in Washington, D.C. were surprised to hear Japanese Defense Minister Taro Kono announce on June 15 that he was halting deployment of the $4 billion Aegis Ashore missile defense system Japan is buying from the United States. This soon became a decision to cancel the use of planned Aegis Ashore sites in Yamaguchi and Akita prefectures, and prompted a broader reconsideration of Japan’s missile defense approach and other aspects of its national security strategy. The remainder of 2020 is shaping up to be an unexpectedly consequential year for U.S.-Japan defense cooperation, and it comes at a time of political uncertainty in both capitals. This calls for focused high-level alliance attention now on Japan’s defense options to prevent strategy gaps from emerging.

A few weeks after Kono’s announcement, an influential group of defense-savvy ruling party politicians in Japan submitted recommendations to the government about next steps for Japan’s missile defense approach, including a suggestion to add more offensive firepower to threaten enemy bases and strengthen deterrence. Tokyo is also considering other moves that could impact Japan’s air and missile defense capabilities including a new fighter jet development program and possible adjustments to its contract for high-end Global Hawk unmanned surveillance aircraft. Meanwhile, North Korea keeps improving its missile technology and could possess up to 60 nuclear weapons that are “probably” miniaturized, according to the U.S. Army and a United Nations report.

The Trump administration’s reaction has been muted so far, but there are serious concerns in Washington about how fast Tokyo is looking to make decisions on next steps and yet how little consensus seems to exist in Japan about the best way to protect the country from missile attacks. Policymakers in Washington know that Aegis Ashore is not a perfect solution for the evolving missile threats Japan faces, but there are no simple alternatives. Any effective response will involve a combination of countermeasures (offensive and defensive, active and passive) that costs money, still leaves gaps, and entails some risk.

In many ways, the current drama surrounding Aegis Ashore and Global Hawk in Japan is a familiar kind of U.S.-Japan friction that accompanies high-profile and expensive defense contracts. Cost overruns and schedule delays are common as marketing promises run into engineering realities, bureaucrats responsible for implementation rotate in and out frequently (undermining efficiency), and difficult political decisions are postponed. In Japan especially, the deployment of military hardware often meets local opposition and produces additional obstacles. But these issues can be addressed without eliminating such programs.

In this case, the shortcomings associated with Aegis Ashore in Japan — e.g., rocket boosters that might fall outside of designated zones and difficulty finding a welcoming host community — were foreseeable early on in Japan’s research about the missile defense system, which began six years ago. Over time, the weight of these and related challenges has grown heavy, and the threats Japan faces have evolved as well, combining to stimulate second thoughts by Kono.

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North Korea is improving its ability to launch saturation attacks and introducing maneuverable systems that could overwhelm Japan’s missile defenses during a large-scale conflict. In addition, China’s development of hypersonic cruise missiles and other evolving kinetic and cyber weapon technologies are prompting some in Japan to worry that too much of Japan’s defense budget is being invested in a missile defense system that could only address one small part of the military dangers surrounding the country. Some alterations might be justified, but the allies cannot afford to waste time in this process and should consider a phased approach.

The ruling party study team in Japan outlined a variety of potential adaptations to the current Aegis Ashore plan but refrained from choosing among them. These include options such as simply building more Aegis missile defense ships or separating the Aegis Ashore radar from the interceptor missiles and placing the latter on or near the sea. The team did recommend introducing “the capability of preventing ballistic missile launches even from within enemy territory,” although it is not clear if this means some kind of boost-phase missile intercept system or a strike capability to retaliate and destroy North Korean missile infrastructure on the ground. The United States has more than just a passing interest in this debate.

Japan’s neighbors have demonstrated a willingness to use force to get their way, so the United States wants Japan to have a robust missile defense that helps prevent conflict because adversaries would doubt their ability to intimidate Tokyo. A strong Japanese missile defense makes the country less vulnerable to military coercion from North Korea, China, or Russia and thus supports an independent Japanese foreign policy. Combined with limited Japanese counter-attack capability and a close and integrated alliance with the United States that promises swift retaliation, upgraded defenses in Japan can help neutralize North Korea’s missile advances and protect regional stability.

The priority for Washington now should be to support actively Japan’s reconsideration of a comprehensive approach to missile defense. For its part, Tokyo should understand that this will require consistent investment over time in a variety of partial solutions to evolving missile threats that help manage the risk, even if they cannot eliminate risk completely. The pause in Aegis Ashore deployment in Japan is an opportunity for the alliance to rethink certain earlier assumptions about the primary threats and to take advantage of emerging technologies. Because some of these technologies will take time to mature, building an adequate missile defense system in Japan will probably occur in phases, with a short-term focus on filling the Aegis Ashore gap and addressing other challenges — such as hypersonic cruise missile defense and building out a counter-attack capability — over the mid to longer term.

For the threats Japan faces today, it still needs a ground-based missile defense system to relieve pressure on its Aegis ships and to defeat North Korean missiles higher up in the atmosphere. This will reduce Pyongyang’s confidence in any small-scale attack on Japan and diminish the value of North Korea’s missile program investments. Some version of Aegis Ashore is probably the most useful approach in the short term given the investments made to date, and this could involve finding new sites for the advanced radar/interceptor missile configuration or splitting up the already-funded radar system and the interceptors to put each component in a more ideal position.

For example, “engage on remote” technology tested in late 2018 could allow the radar to be situated in a secluded mountain location with interceptor missiles located near or on the sea (either on a sea-based platform or disbursed among various ships). This will still require additional time, testing, and investment to make it work effectively. To mitigate the growing cruise missile threat, other types of defenses should be explored such as hyper velocity projectiles or directed energy weapons. Also, as North Korea improves the maneuverability of its missiles, yet another mid-tier layer of missile defense might be needed to defeat those targets.

This is not to suggest that Japan should engage in an endless spending spree trying to ensure it is safe from every possible threat. The goal is to be effective enough to diminish an attacker’s confidence, strengthen alliance solidarity, and facilitate an effective alliance response. U.S.-Japan cooperation in developing these technologies can also help reduce the financial burden to each partner. In addition to these active means of missile defense, passive measures such as improving surveillance capabilities, information sharing, and the resiliency of critical infrastructure are important as well.

Finally, to complement active and passive defenses, Japan should also work to improve its counter-attack capabilities so that it can limit an enemy’s repeated strikes against Japan. Because missile defense is relatively expensive and can be less effective in the face of persistent attacks, Japan should be able to significantly disrupt the attacker after an initial salvo. The United States will help with this too, of course, but the alliance will be more effective and efficient if they integrate both offense and defense capabilities more tightly. Japan is already moving in this direction with planned purchases of air-launched missiles that can hit targets on land and sea from up to 1,000 kilometers away, but Japanese leaders have consistently interpreted their constitution as limiting such strikes only for self-defense and only after Japan is attacked.

The military strength of North Korea and China cannot be ignored, and while missile defense is not the only means to protect against military intimidation, unlike counterstrike capability it can mitigate damage at the start of an attack. Missile defense in Japan also supports U.S. interests and U.S.-Japan security cooperation. Alliance defense and foreign policy officials from at least the director general/assistant secretary level should work to build a quick consensus on realistic next steps to solidify missile defense in Japan and develop an implementation plan in partnership with political leaders and industry. A possible meeting on August 29 between Kono and U.S. Secretary of Defense Mark Esper could be a way to bolster this dialogue. Waiting until 2021 to get serious about this is too late.

James L. Schoff is a senior fellow in the Asia Program at the Carnegie Endowment for International Peace and organizer of the U.S.-Japan Defense Equipment Cooperation (DEC) Roundtable, a non-partisan bilateral study group of defense specialists and corporate representatives in Washington, DC.