Given the potential ramifications, these changes to Japan’s security posture need to be debated extensively in Japan and placed within the historical context. It is important that the Japanese government clearly explains to both its citizens at home and allies and partners abroad why changes are necessary and how they are part of a natural historical progression of Japan’s exclusively defence-oriented security policy framework. Given Japan’s history in Asia, it is natural that its neighbours would be sceptical of any changes in Japan’s security policy, and many people in the region are concerned that any talk of collective self-defence is a signal of a rightward hawkish tilt. However, experts across the political spectrum in Japan recognise that moderate changes to the interpretation of the constitution can contribute to long-term stability and peace in the region.

The idea that laws governing the Japan Self-Defense Forces (SDF) and its operations must be consistent with the constitution remains a central tenet of Japan’s post-war alliance policy thinking. At the same time, it is widely understood that Japan’s defence capabilities must also adapt to the ever-changing regional security environment. But the current interpretation of the constitution, stipulating that the exercise of the right to collective self-defence is not permitted, was established during the Cold War and fails to respond to the demands of the current security environment.

For instance, in the hypothetical case of an emergency situation on the Korean Peninsula, if Japan were to help the United States track a North Korean fighter jet and the US military subsequently shot the jet down, this would be considered an integration with US military forces and an unconstitutional exercise of collective self-defence under the current interpretation. But if Japan cannot help the United States under such circumstances, the alliance will undoubtedly be undermined.

Before Japan makes a hasty change in the way it interprets the constitution, two points of contention need to be carefully considered. First, how would a change of interpretation fit into a comprehensive US-Japan alliance strategy aimed at enriching the regional security environment? If alliance policy is debated only from a military viewpoint, it risks giving the wrong impression to regional neighbours and exacerbating the security dilemma. In other words, security policy changes not coupled with diplomacy may trigger countermeasures by neighbours, worsening the overall regional security environment. Thus changes to the SDF force structure to boost Japan’s capabilities to defend outlying territories should be done in a calm and transparent manner. At the same time, the United States and Japan should promote a comprehensive approach to alliance strategy that puts diplomacy at the centre of all policymaking and brings China into the fold as a responsible regional stakeholder by focusing on confidence-building measures, cooperation on trade and investment, rule building, and joint energy cooperation. Given the shifting balance of regional power, such a comprehensive approach to alliance strategy is even more important now than it has ever been.

Second, given the unified position of the Japanese government — that the exercise of the right to collective self-defence is not allowed by the constitution — a clear and rational explanation must be given before the interpretation is changed in order to maintain national integrity. This must take into account the sequence of events that led Japan to this point as well as the changing nature of the regional security environment, and maintain the spirit of the constitution’s Article 9 peace clause. Failure to rationally explain changes in their proper context will arouse the suspicion of neighbouring countries and worsen the regional security environment.

Considering the complex context discussed above, any reinterpretation of the constitution should be limited to the following two aspects to maintain consistency with past national security policy but also respond to the challenges of the current international security environment.

First, collective self-defence missions authorised by the international community through the UN Security Council, which includes China and Russia, should be recognised by all parties as permissible exceptions to the restriction on collective self-defence. The conduct of SDF personnel in UN-led Peacekeeping Operations (PKOs) must be held to the highest international standards, but imposing conditions on SDF troops, as per the 1992 PKO Law, beyond those of other UN PKO soldiers is unnecessary and complicates the already difficult task of restoring peace in volatile situations.

Second, restrictions on the exercise of collective self-defence should be lifted for scenarios that directly affect Japanese national security. Given that Japan has already established the ‘Law Concerning Measures to Ensure the Peace and Security of Japan in Situations in Areas Surrounding Japan’, and that the United States is obligated to defend Japan against attacks as per Article 5 of the US-Japan Security Treaty, it is natural that Japan and the United States should cooperate on planning and implementation of defensive operations in such scenarios.

It is, however, unnecessary to change the interpretation so radically that all aspects of the exercise of collective self-defence are permitted by the constitution or that the SDF would be able to participate in US operations anywhere around the globe. Reinterpretation outside the scope of the two above-mentioned aspects would break with the exclusively defence-oriented nature of post-war Japanese security policy and would risk arousing distrust of Japan’s intentions.

Maintaining an exclusively defence-oriented security policy framework while also adequately facing up to the security challenges facing Japan and the rest of the region requires a careful balancing act. This is the crux of the security dilemma. Reinterpreting Japan’s constitution to recognize the exercise of the right to collective self-defence in strictly limited circumstances — namely unfettered Japan SDF participation in UN-led PKOs under the direction of the UN Security Council and defensive operations to protect Japanese territory and the lives of Japanese citizens — is a rational progression that builds upon Japan’s past national security policy while maintaining a liberal internationalist strategic outlook.

Hitoshi Tanaka is a senior fellow at the Japan Center for International Exchange (JCIE) and chairman of the Institute for International Strategy at the Japan Research Institute, Ltd. He previously served as Japan’s deputy minister for foreign affairs.

This article is a digest of JCIE’s East Asia Insights policy brief Vol. 9 No. 1 which is available in full here.