Underscoring the Japanese government's commitment to the Japan-U.S. alliance and keeping North Korea in check was the main purpose of Defense Minister Itsunori Onodera's Aug. 10 statement that Japan could intercept a threatened North Korean missile launch toward the U.S. island territory of Guam.
Onodera was asked by opposition Democratic Party (DP) legislator Yuichi Goto at an out-of-session meeting of the House of Representatives Committee on Security at the Diet on Aug. 10, "How would Japan's existence be threatened by an attack on Guam?" The defense minister responded that a degradation of U.S. striking capabilities and deterrence power could constitute a crisis threatening Japan's existence, and warrant Japan's limited exercise of the right to collective self-defense.
With the enforcement of new security-related legislation in 2016, the government stipulated that a crisis threatening Japan's existence would make the nation's limited exercise of collective self-defense possible. Additionally, the crisis must fulfill the "three new conditions" for the use of force, one of which is "a clear danger to citizens' rights being overturned."
The bedrock of Japan's national security comprises a "shield" and a "pike" based on the Japan-U.S. security alliance. The defense-oriented Japan Self-Defense Forces (SDF) dedicates itself to being a "shield," while Japan relies on the U.S. military's massive might to be its "pike." Meanwhile, Guam, which North Korea has singled out as a target, serves as a hub for the U.S. military's stealth bombers and nuclear-powered fast-attack submarines.
There is deeply rooted sentiment within the Japanese government that failing to respond to attacks on U.S. vessels and territories would put the Japan-U.S. alliance at risk, and Onodera's Aug. 10 remark is believed to have reflected such concerns.
However, Onodera's statement that Japan could exercise its right to collective self-defense refers to that possibility in the legal sense. Japan has just four Aegis vessels with missile interceptor systems, and these systems' missiles are said to be incapable of reaching the altitudes at which ballistic missiles would be heading toward Guam. There are Japan-U.S. plans to introduce next-generation Aegis missile defense systems, but even then, some point out, it would be difficult to intercept long-range missiles.