In this March 6, 2017, file photo, a member of the Japan Self-Defense Forces stands by a PAC-3 Patriot missile unit deployed against the North Korea's missile firing, at Defense Ministry in Tokyo.

In this March 6, 2017, file photo, a member of the Japan Self-Defense Forces stands by a PAC-3 Patriot missile unit deployed against the North Korea's missile firing, at Defense Ministry in Tokyo. Shizuo Kambayashi/AP

Japan Needs Long-Range Strike Capabilities

Ballistic-missile defense systems alone can’t ward off regional threats. Tokyo needs firepower to deter its enemies.

There is a term to describe the mindset of Japanese people who put so much faith in Japan’s peace constitution that they are complacent about security threats. They are said to suffer from heiwa-boke. With North Korea demonstrating increasingly sophisticated missiles and threating to sink the country with nuclear weapons, heiwa-boke is a luxury the country can no longer afford. A serious national debate is long overdue about what Japan needs to ensure its survival.

Japan’s effort to meet regional missile threats rests largely on a two-tiered ballistic missile defense, or BMD, system. The sea-based tier consists of destroyers equipped to intercept missiles in midcourse, outside the earth’s atmosphere. The land-based tier consists of Patriot missile batteries designed to intercept missiles in their terminal phase. Overall, Japan’s BMD system is advanced, but there are limits to what it can do. According to unclassified sources, the PAC-3 interceptors that Japan deploys in its Patriot systems have a range of about 12.5 miles, making them useful only if they happen to be placed quite near an incoming missile’s target. The destroyers and their Aegis combat systems, by contrast, can potentially protect the entire country, but the ships must be in the right place at the right time. Whether any of this covers a specific area in Japan depends on when and where the missile drops. Worst of all—for the U.S. and consequently Japan’s value for regional missile defense—the missiles North Korea fired in August and September over Hokkaido flew at a speed and lofted trajectory that put them out of reach of Japan’s BMD completely.

To fill in the gaps, Japan could proceed with plans to purchase the land-based Aegis Ashore system and deploy more advanced missile interceptors for Japan’s sea-based and land-based systems, adding range, altitude and accuracy. While these capabilities would not protect all 127 million Japanese, especially if North Korea fires multiple missiles or uses multiple independently targetable reentry vehicles, it would provide a much better chance at interception than the current system.

But Japan is also legally constrained in how it can act. When the country passed legislation in 2015 enabling Japanese forces to exercise collective self-defense, Prime Minister Shinzo Abe attached strict conditions on its use. Japan is allowed to exercise force, and to the minimum extent necessary, only when its survival is threatened — either by direct attack or an attack against a country with a close relationship to Japan — and there are no other means to repel the attack.

The North Korean missile threat illustrates how difficult it is for Japan to actually exercise collective self-defense. Within seconds of a launch, Tokyo would have to determine the missile’s likely trajectory; if it appeared to be aimed not at Japan but elsewhere, its political leaders would have to discuss whether the situation fulfilled the conditions of collective self-defense. Could they realistically reach this conclusion fast enough to intercept the missile? And even if so, can Japan legally shoot down a missile unilaterally in the name of collective self-defense before any other country acts? Probably not.

To boost its deterrence capabilities, Japan should consider being even more proactive. It should, in fact, contemplate acquiring the capability to strike enemy territory with long-range strike capabilities. Under the notion that Japan should not simply wait around to die if an enemy were preparing to attack, the Ichiro Hatoyama administration argued in 1956 that having capabilities that could strike enemy missile sites was theoretically within the constitutional right of self-defense. This interpretation even applied to Japanese strikes against another country before a missile is launched at Japan. Subsequent administrations have adhered to this interpretation, meaning Japan can constitutionally possess long-range strike capability. As a matter of policy, however, its governments have not tried to acquire them. It may be time to move beyond the theoretical.

Assuming Japan needs long-range strike capabilities and plans to stay true to its commitment to self-defense, the government would need to clarify that the missiles would not be used preemptively. Yes, the technology is the same. So is the legal basis. The difference lies in the optics and reality of the situation. “Preemptive” looks offensive because it is extremely difficult to prove Japan is acting in “self-defense” when an attack on Japan has not yet occurred. The premise for initiating an attack also complicates the matter—being able to determine with absolute certainty that a launch is imminent, that the missile will strike Japan, and there are no other means to defend Japan. Easier said than done. 

It would be politically difficult for Abe to acquire strike capabilities. He would be criticized for trampling on Japan’s pacifist constitution. The domestic opposition would likely argue that long-range missiles are “war potential” prohibited by the constitution. And countries such as China would probably complain that Abe is remilitarizing Japan.

But the government has a responsibility to protect the lives and property of its citizens. Facing a country like North Korea, which has threatened Japan’s very existence, leaders must do everything within their grasp to protect the country. If the existing BMD system has gaps, any means for Japan to strengthen its deterrence capabilities should be welcomed. The heightened threats from North Korea could be viewed as a call for new action.

For most of the past seven decades, Japanese political leaders could only improve security policies as fast as the pacifist public allowed. This worked during the Cold War when the technology of the Soviet Union did not change rapidly. After that era, Japan’s security policies continued to adapt to meet new challenges, albeit slowly. But North Korea’s swiftly advancing military capabilities have drastically changed the threat environment. Japan no longer has the luxury to be complacent about its security threats. It should consider making strike capabilities a top priority.