When North Korea launched a ballistic missile over Japan in August, the Self-Defense Forces (SDF) did not try to shoot it down with anti-missile systems. The Mainichi answers some common questions readers may have about why the SDF didn't take any action.
Question: So, why didn't Japan shoot down that North Korean missile?
Answer: The only circumstances in which the SDF is allowed to shoot down a missile not directly aimed at Japan is if there is a risk it will in fact hit this country and inflict damage both human and material. Based on radar data, it was judged that there was no risk of the missile North Korea launched in August landing on Japan, and so there was no attempt to intercept it.
Q: But I've heard that the SDF has deployed anti-missile units. Is that so?
A: North Korea threatened to target its ballistic missiles at the area around the U.S. Pacific island territory of Guam. Japan's Ministry of Defense then deployed PAC-3 Patriot missile batteries to SDF bases in the Chugoku and Shikoku regions, which are likely to be beneath the path of any North Korean launch towards Guam. It also deployed Aegis vessels equipped with SM-3 interceptor missile systems in the Sea of Japan. These preparations were made to guard against a Guam-bound ballistic missile landing on Japan due to a malfunction.
Q: But isn't it true that the defense minister said the SDF could shoot down a ballistic missile aimed at Guam?
A: If a ballistic missile was fired at Japan in a deliberate attack, the government could invoke the right to protect itself and shoot down that missile as part of an overall defensive deployment. It is also now technically legal for Japan to shoot down a missile aimed at its ally the United States by invoking the right to collective self-defense.
Q: I've read that limited use of the right to collective self-defense is now permissible, but would an attack on Guam qualify?
A: Guam is home to major U.S. Navy and Air Force bases. If those bases were attacked, Tokyo could judge that any weakening of the U.S. military -- which shares responsibility for the defense of Japan with the SDF -- constitutes a threat to Japan's survival, and invoke the right to collective self-defense. However, the SDF's current interceptor systems are thought to be incapable of shooting down a Guam-bound ballistic missile. (Answers by Shinichi Akiyama, Political News Department)