Author: Daniel Gearin, Center for a New American Security

There are fewer nuclear weapons in the world today than in the past, but more states are in possession of them. Meanwhile, the United States has adopted a policy that de-emphasizes the importance of nuclear weapons, which has raised questions about whether the United States maintains its deterrence capability. This policy change is largely due to the end of the Cold War and the reduction of the nuclear threat from the Soviet Union, and is evident in the recent New START (Strategic Arms Reduction Treaty) Treaty that seeks to significantly reduce the number of Russian and American nuclear missile launchers. While these developments appear to be a natural response to the changing global strategic environment from the perspective of the former Cold War rivals, other countries face a more threatening strategic environment today than in the past. The changing nuclear balance in Asia creates a unique challenge for Japan in particular, as it seeks to maintain a credible deterrence while dealing with emboldened regional adversaries.

Recent changes in Japan’s National Defense Program Guideline (NDPG) provide insight into the evolving views of Japanese policy makers toward nuclear issues. Takahashi Sugio of the National Institute for Defense Studies noted that Japan is concerned with two challenges in the realm of nuclear deterrence; deterring the actual use of nuclear weapons, and how a changing nuclear balance can influence the behavior of regional powers. For Japan, the latter challenge is more important than the former for determining and implementing nuclear deterrence policy.

For the foreseeable future, Japan’s policies surrounding the issue of nuclear assurance will continue to rely on the support of the United States and its nuclear umbrella. In order for Japan to be properly assured, the declaratory policy of the United States which explicitly extends its nuclear weapons over the protection of Japan goes a long way. The United States has repeatedly reiterated its defense commitments to Japan after security incidents have occurred in the region, which further reconfirms Japan’s feelings of reassurance. Most recently, after the Diaoyutai/Senkakku Island incident with China, U.S. Secretary of State Hilary Clinton stated that the uninhabited islands fell within the scope of a U.S.-Japan security treaty. As this territorial dispute remains a significant source of tension for Sino-Japanese relations, the reassurances provided by the U.S. toward Japan’s defense are well received. In Japan, the concepts of deterrence and assurance are closely linked, and the United States plays an important role in bolstering Japan’s security confidence.

Martin Fackler of the New York Times highlighted the persistent feelings of assurance in Japan provided by the United States, which helps explain why there is little public debate in Japan regarding acquiring nuclear weapons. This reliance on the U.S. nuclear umbrella to provide for Japanese the security guarantee of Japan will likely continue into the future for as long as the United States maintains its forces in Japan. If the United States were to relocate its bases and troops outside of Japan completely, it would probably have significant policy implications and provide further impetus for Japan to reconsider its own domestic nuclear options. Given the lingering historical grievances in the region, and the current tensions, such a policy shift on the part of Japan could have serious implications.

Victoria Tuke from the University of Warwick highlighted the differing perceptions of deterrence that exist between Washington and Tokyo. In the post-Cold War context, the United States perceives terrorism as the greatest threat to its national security, along with a variety of other non-traditional security threats such as cyber-attacks, piracy, etc. The nature of these various threats makes the functionality and viability of nuclear weapons less convincing, which has had a wider affect on U.S. nuclear policy. Meanwhile, Japan continues to view state actors as the primary source of security threats, particularly regional state actors that are in possession of nuclear weapons. These differing threat perceptions invariably influence how the respective countries view the applicability and utility of nuclear weapons today, in both deterrence terms and otherwise.

Despite the fact that U.S. commitment to Japan is unlikely to change in the short term, there are a number of changes taking place in Japan’s external environment that are troubling for its security situation. North Korea has long served as a source of insecurity for Japan in the region, and its recent acquisition of nuclear weapons has only heightened Japan’s sense of vulnerability. The continuous provocations from Pyongyang exacerbate the deteriorating security environment in Asia, and will likely make Japan increasingly sensitive towards perceived shifts in the U.S. security guarantee. The push for a stronger and more militarily capable Japan that characterized the Koizumi Administration could become even more likely in the current security environment, especially if the United States commitments appear to be waning. Furthermore, the rise of China is increasingly becoming a cause of concern for defense officials in Japan. These various changes are all contributing to rising anxiety in Japan over the future of the U.S-Japan alliance and the challenges it faces.
The Nuclear Posture Review (NPR) provides a lengthy discussion on regional deterrence strategies. It seeks to reduce the role of nuclear weapons by using a more comprehensive mix of tools. The implications of this publically stated policy remain unclear. Are allies more nervous that the United States appears less willing to use nuclear weapons, or are they reassured that the United States is looking to provide a larger basket of tools? Furthermore, the United States must be more explicit in the future on what it is seeking to deter. Existing policy makes it clear that an attack on a U.S. or allied-city would elicit a response, but what about an attack on a ship? Other non-traditional security threats (including embargoes, or cyber attacks) make this dilemma all the more difficult to solve, thus increasing the need for an explicit statement.

The Japanese in particular seek reassurance that the United States is willing to use the full extent of its security force (including nuclear weapons) to come to its aid in a crisis. In light of current changes taking place in U.S. policy, it is important to convince Japan that the changes are in their interest. A more comprehensive basket of tools for dealing with security concerns is actually better for the alliance than a reliance on nuclear deterrence. This is clear in light of the most recent and pressing security concerns facing Japan, and the other U.S.-allies in Asia.

Despite the existing nuclear umbrella guarantee, both the shelling of Yeonpyeong island and the sinking of the Cheonan occurred. Clearly, nuclear weapons were not enough to dissuade North Korea from carrying out these provocations. Developing a set of alternative responses that are more likely to be employed than nuclear weapons, and thus more credible, could bolster the deterrent capability of an alliance with the United States.

Since the Democratic Party of Japan (DPJ) came into power, the United States and Japan have encountered difficulties in negotiating the future of the U.S. military presence in Japan. The fate of the United States Marine Corps Air Station Futenma has been a longstanding source of contention between the two allies, and the final outcome remains unclear. Although this problematic issue is unlikely to influence the overall security alliance between the two countries, the tension it has caused has clearly strained short term relations. The successful resolution of this issue will be important for bringing the relationship back on a more positive track, which would have at least an indirect affect on the larger tone of defense relations.

Meanwhile, the financial atmosphere in Japan has created additional pressure for the future of the country’s defense spending. Although there have been new commitments in certain areas of its military, the overall defense budget of Japan has continued to decline over the past decade. The sluggish performance of the Japanese economy is projected to continue for the foreseeable future. This setting has increased Tokyo’s dependence on the security guarantee provided by Washington, and this is unlikely to change soon. The fiscally austere climate within both countries strengthens the case for collaboration and burden-sharing in the security realm, as neither country is capable of doing too much on their own.

* The views expressed herein do not necessarily reflect the views of the Asan Institute for Policy Studies.
* The views expressed here are panel overviews of the Asan Plenum. They do not necessarily reflect the views of the author or the institutions they are affiliated with.