It is vital to consider measures from various perspectives to strengthen Japan’s defense against the threat of North Korea’s nuclear and missile development, which has entered a new stage.
Defense Minister Tomomi Inada inspected a Terminal High Altitude Area Defense (THAAD) advanced ground-based missile defense system at Andersen Air Force Base in the U.S. territory of Guam. Inada expressed her willingness to introduce THAAD in Japan, saying, “It could be a way to enhance capabilities.”
THAAD is designed to be mobile and intercept enemy missiles outside the atmosphere or at high altitudes. The antimissile system is scheduled to be deployed to the U.S. military stationed in South Korea this year.
Japan’s current missile defense is a two-tier system. The Standard Missile-3 (SM-3) installed on Aegis destroyers shoots down missiles outside the atmosphere, while Patriot Advanced Capability-3 (PAC-3) surface-to-air guided missiles intercept them at an altitude of about a dozen kilometers. The introduction of THAAD would mean covering “gaps” unfilled by SM-3 and PAC-3 interceptions.
The Defense Ministry plans to soon set up a committee tasked with studying ways to reinforce the nation’s missile defenses. The panel is likely to reach a conclusion as early as this summer with an eye on drawing up the next Medium Term Defense Program to be implemented for fiscal 2019 to fiscal 2023.
Last year, North Korea fired more than 20 ballistic missiles, four of which fell into waters near Japan. Amid concerns that Pyongyang has improved its ability to launch missiles faster and strike targets accurately, it is necessary to bolster Japan’s interception capability.
Address need for attack ability
In fiscal 2017, the Defense Ministry plans to start acquiring the SM-3 Block 2A system, a sea-based interceptor missile system more capable of identifying targets at a longer range. The ministry also plans to increase the number of Aegis destroyers equipped with SM-3 missiles to eight from four by fiscal 2020. In addition to steadily implementing such plans, efforts to consider new measures are also desired.
THAAD has been successful in 13 interception tests since 2006. However, a single unit costs more than ¥100 billion.
The idea of a land-based Aegis system has also been floated. This system would cost less than THAAD, but it could become a target of attack because it is not mobile.
A level-headed analysis is needed on both missile defense systems from such perspectives as cost-effectiveness and how they would combine with the existing interceptor systems.
There is an issue as to whether bolstering only the ability to intercept missiles is good enough. If many missiles are launched at the same time, shooting all of them down would be difficult.
The Institute for International Policy Studies has proposed that Japan obtain the ability to attack an enemy’s launching base, such as by using cruise missiles. The government should give the idea serious consideration.
Interceptor missiles are capable of air defense only, but cruise missiles can be adapted for various missions, including protecting remote islands. An attack on an enemy base that poses an imminent danger of firing a missile is regarded as being within the scope of self-defense and would not cause a constitutional problem.
If the Self-Defense Forces have such attack ability in a way to complement the U.S. military, the deterrent capabilities of the Japan-U.S. alliance would increase further.