The Japanese government has put forward several reasons for establishing its own missile defence system. First, the significant international proliferation of ballistic missiles and weapons of mass destruction (WMD) represents an emerging threat. Second, Japan currently has no system that can defend its territory and people in the case of a ballistic missile attack, and there is currently no viable alternative to missile shield systems such as the BMD system. Third, the government has claimed that Japan’s missile program is purely for defensive purposes, emphasising that the BMD system will not pose any threat to other states due to its defensive posture in line with Japan’s senshu boei (exclusively defence-oriented defence) policy.

Aside from these three considerations, some have argued that the development of a BMD system will promote defence and security cooperation with the US, while others contend the system’s development will have positive spin-off effects for the Japanese economy.

Whatever the justifications, Japan’s strong bureaucracy is the most significant factor promoting the country’s BMD program. It has played a key role in maintaining the long-term consistency of the government’s policy toward BMD throughout Japan’s frequent regime transitions. More specifically, the government’s long-term position on the BMD program can be attributed to Japan’s security policy-making process, in which bureaucrats from the Ministry of Defence (MOD) and Ministry of Foreign Affairs take charge in making concrete decisions and crafting policy. The government maintains that the missile defence issue is an operational-level matter in the MOD and Self-Defence Forces, and thus claims it is not necessary to consult the Diet or seek its approval.

Still, there are numerous debates in Japan centring on the BMD program. The first debate focuses on interpretations of the Japanese constitution’s article 9 peace clause. The Japanese government currently interprets the constitution as prohibiting Japan’s participation in ‘collective self-defence’ and justifies the maintenance of the Self-Defence Forces by limiting their mandate to ‘individual self-defence’. The most obvious scenario of ‘collective self-defence’ would be Japan participating in US military operations abroad as an ally. The second debate centres on the possibility of Japan transferring its BMD technology to South Korea or Taiwan, potentially violating the Three Principles on Arms Export, which prohibits the export of weapons. And the third debate centres on the deployment of an upper-tier defence system and its potential to violate the 1969 Diet resolution on the peaceful use of outer space.

In any case, these inhibiting factors will not slow down the momentum toward building missile shields, especially with Japan’s formidable bureaucracy throwing its weight behind the project. Developing the cutting-edge technology necessary for the BMD program also requires significant financial resources, and it appears that not even the economy’s long-term stagnation or the 2011 disasters are stalling the development of Japan’s BMD program.

Despite the government’s claim to possess only self-defence-oriented intentions, its BMD program could be considered an offensive ‘double-edged sword’. That is, the development of Japan’s BMD program may still be seen as a threat to neighbouring states and cause a regional arms race that could lead to conflict. Also, because Japan and the US are close allies, critics may connect Japan’s BMD system with the offensive capabilities of the US, thus building on the impression that combined Japanese and US forces could constitute a significant war-fighting capability in the region. The Chinese government has repeatedly objected to the BMD program, which it regards as a revival of Japanese militarism and as part of the strategic enlargement of US forces in East Asia.

But Japan’s BMD system could potentially lead to regional arms control and possibly nuclear disarmament if neighbouring states trust that it is a logical continuation of Japan’s senshu boei (exclusively defence-oriented defence) policy. To promote this perception, Japan must make a careful distinction between offence and defence, and clearly emphasise the program’s defence-oriented intentions. Japan should also promote its cooperation with the US as a means to move toward a global reduction of offensive weapons, including nuclear weapons. And finally, Japan should take the lead in establishing a global arms control regime that emphasises defence. Australia should be a significant partner in this, as it too is an important ally of both the US and Japan, having cooperated with the US in its missile defence program and deepened its security cooperation with Japan.

Norifumi Namatame is Visiting Fellow at the Australian National University, and Associate Professor at Tohoku Fukushi University, Japan.