TOKYO — Japan has deployed interceptor missiles in case North Korea goes through with its threat to fire missiles into waters near U.S. territory, but what happens next remains unclear on many levels.
Pyongyang last Thursday threatened to fire four ballistic missiles into the Western Pacific Ocean near Guam, on a flight path that would take the projectiles over western Japan’s Shimane, Hiroshima and Kochi prefectures. Were these rockets to land in Japan, perhaps accidentally due to failure mid-flight, they would do so several minutes after launch, according to an official at the Ministry of Defense. They could also rain down debris including missile parts and fragments.
Taking no chances
On Saturday, the Defense Ministry deployed Patriot Advanced Capability-3 surface-to-air missile systems, which are designed to intercept debris or missiles within a radius of tens of kilometers, in those prefectures, as well as neighboring Ehime Prefecture. The government is “on high alert” and “will do our best to ensure no harm comes to our citizens,” Prime Minister Shinzo Abe said Monday when he met with those prefectures’ governors at his official residence in Tokyo.
While 17 Air Self-Defense Force units operate 34 PAC-3 systems around Japan, none of the missile defense systems were deployed in the country’s Chugoku region, including Shimane and Hiroshima, or on the island of Shikoku, which includes Ehime and Kochi prefectures, until last week.
According to the government, the interceptor missiles would neutralize any nuclear or chemical weapons aboard a ballistic missile, shielding the areas below from any ill effects.
Heading off a projectile before it reaches waters near Guam could be more difficult, since it would pass over Japan at an altitude of hundreds of kilometers, while PAC-3s have a range only in the tens of kilometers.
The SM-3 missile defense batteries deployed on Japan’s four Aegis destroyers, which are now patrolling around the clock, mainly in the Sea of Japan, may stand a better chance, given that they are designed to intercept missiles outside the Earth’s atmosphere. Still, those systems are intended to shoot down missiles once they have reached the peak of their trajectory and have begun to descend. “Missiles that had just been fired from North Korea and were passing over the Japanese archipelago would likely be ascending,” according to a Defense Ministry official.
Intercepts on the U.S.’s behalf would also raise legal questions. Defense Minister Itsunori Onodera noted before a lower house committee Thursday that the missile attack North Korea has threatened might constitute an “existential threat” of the sort that would allow Japan to exercise so-called collective self-defense, and to come to the Americans’ aid even though Japan itself had not been attacked. As the government sees it, a threat on Guam, a key U.S. military base in the Asia-Pacific, would rattle the Japan-American defense alliance in a way that could threaten Japan’s existence.
But exercising collective self-defense requires that the U.S. be under armed attack by an enemy nation before Japan can act. Neither America nor North Korea has yet engaged in any sort of armed strike on the other. And the missile strikes Pyongyang has threatened are targeted 30km to 40km off Guam’s coast — outside the 12-nautical-mile (roughly 22km) range that defines territorial waters. It is far from clear whether this can be considered an attack on the U.S.
The U.S., of course, could always act on its own. Japan is expected to provide logistical support to American troops and escort U.S. vessels in the event of military conflict on the Korean Peninsula. And while Pyongyang’s declaration that its missiles will land outside U.S. territorial waters may be aimed at avoiding such a contingency, Washington could still regard such missile launches as attempted attacks, and initiate a military response.