Japan’s Nuclear Policy: Between Non-Nuclear Identity and US Extended Deterrence
Satake Tomohiko of the Australian National University discusses the two apparently incompatible factors which have shaped Japan’s ‘non-nuclear policy’ in the post-World War Two era: “Japan’s non-nuclear identity and its reliance on the US nuclear umbrella. Satake argues that “as Japan perceives greater threats from its region, it will face a dilemma that inherently exists in its nuclear policy: policymakers in Japan will be required to pursue a more deliberate nuclear strategy than before between demands for preserving a non-nuclear identity on the one hand, and maintaining credible US nuclear deterrence on the other.” Satake concludes that “managing regional threats and uncertainty is important not only for enhancing Japanese security, but also for reducing its dependence on US nuclear protection. Such a policy will mitigate the problem of the ‘nuclear dilemma’ in Japanese non-nuclear policy over the long term. This will enable the Japanese government to continue to work towards nuclear non-proliferation and disarmament while maintaining its non-nuclear national identity in the years to come.”
Essay: Japan’s Nuclear Policy: Between Non-Nuclear Identity and US Extended Deterrence
The current shift within the international security environment of the Asia-Pacific region has once again stimulated international debate on Japan’s nuclear policies. Since North Korea appeared to develop nuclear weapons in the early 2000s, a number of current and former US officials have mentioned the possibility of Japan developing a nuclear armament in response.  Some US officials have even argued that the US should encourage Japan to develop a nuclear capability in order to cope with North Korea’s nuclear development and to accommodate the rise of China.  This discussion also became a hot issue in Australia. Last year Hugh White, a well-known defence analyst in Australia, argued that Japan might ‘go nuclear’ by seeking greater independence from the US in response to China’s growing power. He also contended that a nuclear-armed Japan would be essential for a stable new international order.  Others criticised White’s argument, by arguing that a nuclear Japan was neither likely nor desirable for the international system. They stressed that Japan would much prefer to maintain reliance on the US nuclear umbrella, rather than become an independent nuclear power. 
Will Japan become a nuclear power in order to balance North Korea, and possibly in the future, China? Or, will it retain its non-nuclear status and continue to rely on the United States to meet its security needs? While there is a number of potential independent variables that could determine the future of Japan’s nuclear policy (e.g., Japanese domestic factors, US foreign policy, technological issues, etc…), I will focus particularly upon two factors—Japan’s non-nuclear identity and its reliance on the US nuclear umbrella—which have shaped Japan’s ‘non-nuclear policy’ in the post-World War Two era. Although these two factors are fundamentally incompatible, the Japanese Government has been able to maintain these different postures as integral parts of its nuclear policy. It is, therefore, highly unlikely that Japan will make a significant shift in its non-nuclear policy, as long as these two factors remain strong in the years to come. Nonetheless, as Japan perceives greater threats from its region, it will face a dilemma that inherently exists in its nuclear policy. That is, policymakers in Japan will be required to pursue a more deliberate nuclear strategy than before between demands for preserving a non-nuclear identity on the one hand, and maintaining credible US nuclear deterrence on the other.
In this essay I will first briefly explain the historical development of Japan’s non-nuclear policy, which is sustained by both its non-nuclear identity and its reliance on the US nuclear umbrella. Second, I will argue that, despite the changing security environment in the Asia-Pacific region, these factors are still playing vital roles in Japan’s non-nuclear policy. Finally, I will give a brief analysis of the future of Japan’s nuclear policy, including its response to the current new momentum for the elimination of nuclear weapons initiative by the US Obama administration.
Historical Development of Japan’s Non-nuclear Policy
Since the end of the World War II, Japan has pursued the ‘non-nuclear policy’ (hikaku-seisaku). It is well known that Japan has the so-called three-non-nuclear principles—not possessing, not developing, and not introducing nuclear weapons into Japan. Yet Japan’s non-nuclear policy not only means domestic policy such as three non-nuclear principles, but also includes other international efforts for the total elimination of nuclear weapons from the world. For instance, Japan has actively committed to the international disarmament and non-proliferation regime, such as the Non-Proliferation of Nuclear Weapons Treaty (NPT) and the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Since 1994, moreover, Japan has annually introduced UN resolutions for the elimination of nuclear weapons to the General Assembly. Other efforts made by Japan concerning nuclear disarmament include: hosting UN conferences on disarmament issues; supporting a nuclear-weapon-free zone in Central Asia; encouraging the negotiation of the Fissile Material Cut-off Treaty; and assisting denuclearisation efforts in the former Soviet Union. Japan also strongly protested against the nuclear tests of both France and China in the mid-1990s. Finally, Japan has recently actively committed to international non-proliferation initiatives such as the Proliferation Security Initiative (PSI). Most recently, Japan launched an International Commission on Nuclear Non-proliferation and Disarmament with Australia in July 2008.
Japan’s non-nuclear policy has been sustained mainly by two pillars. On the one hand, Japan’s domestic norm or identity as a ‘non-nuclear state’ has strictly constrained Japan’s nuclear option and encouraged its non-nuclear policy. Due to their traumatic experience during World War II, the majority of Japanese people believe that nuclear weapons are essentially immoral and should be totally eliminated. Japan’s traumatic experience with atomic bombs has not only been from Hiroshima and Nagasaki, but also from the Fukuryumaru no. 5 incident in 1954—because of the first US hydrogen bomb test on the Bikini Atoll, one Japanese fisherman who bathed in the radioactive fallout died and other fishermen were hospitalised for more than a year. The incident provoked a massive anti-nuclear movement from the Japanese public, and calls were made for the abolishment of all nuclear weapons from all countries. It was from this context that the Japanese Government adopted the Atomic Energy Basic Law, which prohibited Japan’s research, development, and utilisation of atomic energy except for ‘peaceful purposes’. Japan also joined the International Atomic Energy Agency (IAEA) in 1957. In 1967, moreover, Japanese Prime Minister Eisaku Sato enunciated the ‘three non-nuclear principles’. Although these principles did not impose any legal constraint on the Government, they have been widely supported by the Japanese public as the symbol of Japan’s non-nuclear identity. Consequently, three non-nuclear principles—especially the first two principles—have strongly restricted Japan’s overall nuclear policy.
Japanese policy elites recognised however, that only maintaining a non-nuclear status could not be a viable national security policy. The logic underlying this position became increasingly apparent as China developed nuclear weapons from the mid 1960s. In the year following the announcement of the three non-nuclear principles Prime Minister Sato officially announced for the first time that Japan would rely upon US nuclear deterrence for its security. He also stressed that Japan’s three non-nuclear principles could not be sustained without the US nuclear umbrella, by incorporating Japan’s reliance on US extended deterrence into ‘four nuclear policies’.  Since then, successive Japanese Governments have always recognised the US extended nuclear deterrence as an integral part of Japan’s non-nuclear policy. Japan’s National Defence Program Outline (NDPO), which in 1976 announced the first long-term defence build-up project since the end of World War Two, took a clear stance against nuclear war. The NDPO explained that ‘Japan will rely on the nuclear deterrent capability of the United States’. It is very instructive that, when the NDPO was approved by the Cabinet in 1976, the Cabinet also decided to set Japan’s defence expenditure under 1% of GDP as an official policy of the Japanese Government. As this episode suggests, Japan’s explicit reliance on US nuclear protection ironically enabled the Japanese government to pursue its ‘pacifistic’ security strategy including its non-nuclear policy without being concerned about the possibility of a nuclear attack by other states. This was why Japan did not fundamentally change its non-nuclear doctrine even after the late 1970s, when the Soviet threat once again intensified.
Japan’s Non-nuclear policy and Changing Security Environments
After the Cold War, some International Relations scholars predicted that Japan would become an independent power from the US by acquiring nuclear weapons because of the changing security environment in the region.  Despite these predictions, and despite Tokyo’s increasing threat perceptions for both China and North Korea, Tokyo has maintained its non-nuclear policy, which is sustained by both Japan’s non-nuclear national identity on the one hand and its reliance on the US nuclear umbrella on the other. For example, the majority of Japanese still believe that nuclear weapons are essentially ‘immoral’ even in the post-Cold War era. One opinion poll surveyed in 2002 showed that 97 percent of Japanese respondents either agreed (77 percent) or somewhat agreed (20 percent) that an international treaty should exist that bans all nuclear weapons.  Another opinion poll in 2005 revealed that only 6 percent favoured Japan’s nuclearisation, while 86 percent were opposed.  In 2007, Japanese Defence Minister Fumio Kyuma resigned from his post, after stating that the American nuclear bombing of Nagasaki ‘could not be helped’ in order to finalise World War Two. Both opposition parties and the domestic audience severely criticised Kyuma’s statement, although this kind of reasoning is widely accepted by the American public. As this episode shows, for most Japanese people, nuclear weapons are still ‘absolute evil’—which cannot be legitimised by any reason or purpose.
On the other hand, Japan has still preferred to be under the US nuclear umbrella, rather than become an independent power. An internal report of the Japan Defence Agency (JDA), which secretly studied the possibility of Japan’s nuclear armament in 1995, suggested that Japan should not go nuclear because of the enormous political and economic costs that would be caused by the opposition of other countries including the United States. It concluded that ‘the best way is to rely on the US nuclear deterrence capabilities’.  In April 1996, Tokyo reconfirmed the US-Japan alliance by concluding the ‘US-Japan Joint Declaration on Security’. The Joint Declaration clearly defined Japan’s greater alliance roles on both regional and global fields, by stressing that the US-Japan alliance is not only for the security of Japan and the Far East, but also for Asia-Pacific security in general. Because of this, many observers pointed out that the Joint Declaration ‘redefined’ the alliance, by expanding the alliance scope from a narrow focus on Japan and the Far East to the broader Asia-Pacific. Yet Japanese policymakers denied this kind of view, by stressing that the Joint Declaration did not ‘redefine’ the alliance, but simply ‘reconfirmed’ it. For them, the most important achievement of the Joint Declaration was not that the alliance expanded its scope, but that the US promised to keep providing extended deterrence to the region even in the post-Cold War era.
Yet US extended deterrence cannot be gained without certain costs. These costs not only mean traditional ‘defence burden-sharing’ such as a significant amount of host nation support to US troops stationing in Japan. In exchange for the continuous US military commitment in the region, Japan became increasingly involved in US regional and global security objectives. After September 11, Japan contributed to US-led wars in both Afghanistan and Iraq, by dispatching the SDF for the first time during war-time operations. While Tokyo clearly recognised the importance of terrorism and WMD issues, the central concern of Japanese policy elites were not those global problems, but how to keep the US military presence in the Asia-Pacific region, where Japan perceives a growing threat from North Korea and China. In fact, Japan’s military contributions to both the war in Afghanistan and the reconstruction effort in Iraq were never significant compared to other allies. Likewise, Japan has joined the US Missile Defence (MD) program and contributed to its Research & Development (R&D). Although Japan joined the MD system primarily for its own defence, Tokyo also recognised that Japan’s entry to the MD system would supplement the US global defence posture against the attack of terrorist or rogue states. By providing moderate but symbolic contributions to US global operations, Japan attempted to maintain a US credible nuclear extended deterrence in the Asia Pacific region, which is indispensable for Japanese security.
Some might argue that Japan’s non-nuclear policy has recently been challenged by North Korea’s nuclear development and its missile tests in both 2006 and 2009. After North Korea’s nuclear test in October 2006, for example, 17.6 percent of respondents agreed with the statement that ‘Japan’s commitment to remain a nonnuclear weapons state should not be absolute, but rather Japan should reconsider its commitment to remain a nonnuclear state depending on changes in the international environment’.  After North Korea’s ‘satellite launching’ in April 2009, moreover, 19.4 percent of respondents supported Japan’s nuclearisation, whereas 72.8 percent disagreed with it.  Furthermore, a member of the Liberal Democratic Party, Japan’s ruling party, reportedly suggested that Japan should imply the possibility of its nuclear development if North Korea does not stop developing nuclear weapons. The statement was, however, soon rejected by the Chief Cabinet Secretary of the LDP. Another senior LDP member even condemned the statement, saying that this kind of argument would ‘ultimately lead to the destruction of the human race’.  It is highly unlikely, therefore, that North Korea’s nuclear development will directly change Japan’s non-nuclear policy, at least in a short period.
Japan’s ‘Nuclear Dilemma’ and Implication for the Future
In sum, even in the changing security environment, the basic structure of Japan’s non-nuclear policy has not been changed—Japan has consistently sought to maintain credible US nuclear extended deterrence in the region, while identifying itself as a non-nuclear state. It is, therefore, highly unlikely that Japan will become a nuclear power by changing its current non-nuclear policy, as long as the Japanese public continues to believe that nuclear weapons are ‘absolute evil’, and as long as the US provides credible nuclear deterrence to Japan. Nonetheless, there is always tension between these two different policy orientations—stressing Japan’s non-nuclear identity on the one hand, and relying on US nuclear protection on the other. The Japanese Government has attempted to reconcile the seeming contradiction between these two very different logical positions, by discriminating between Japan’s immediate request for membership under the US nuclear umbrella on the one hand and its long-term goal for the elimination of nuclear weapons on the other. 
Nevertheless, there were certainly cases in which Japan’s non-nuclear identity and its reliance on US nuclear deterrence contradicted each other. During the Cold War, for instance, it was highly likely that the third point of Japan’s non-nuclear principles—not permitting the introduction of nuclear weapons—was actually broken many times by the entry of US ships with nuclear weapons to Japanese bays. These nuclear weapons were brought to Japan for deterrence against the Soviet threat in the region.  Another example is the relationship between Japan’s global agenda for nuclear disarmament and its regional security policy in the post-Cold War era. Since it signed the CTBT in 1996, Tokyo has been frustrated by the negative attitude from the US towards the CTBT, even to the point of explicitly criticising the US nuclear posture as ‘unilateralist’. However, since the escalation of North Korea’s nuclear threats in late 2002, these criticisms of US unilateralism have been mitigated by the Japanese public’s increasing awareness of the perceived threats posed by the North’s nuclear weapons. Consequently, Japan even officially requested the Bush administration not to rule out the use of US nuclear weapons against North Korea as a means to assure security against North Korea.  Although it might not have directly clashed with Japan’s overall nuclear disarmament policy, the episode showed there is always tension between Japan’s national identity as a non-nuclear state on the one hand and its enormous dependence on the US nuclear umbrella on the other.
Japan’s ‘nuclear dilemma’ can also be found in its response to the current new momentum for the elimination of nuclear weapons. In his historic speech at Prague on April 2009, US President Barack Obama stated ‘clearly and with conviction’ that the US would commit to seek the peace and security of a world without nuclear weapons. He also mentioned that ‘as the only nuclear power to have used a nuclear weapon, the United States has a moral responsibility to act’. At first glance, Obama’s strong support for nuclear disarmament seems to completely suit Japan’s national identity as a non-nuclear state. This is why the Japanese Foreign Minister quickly announced Japan’s strong backing for Obama’s initiative and later addressed Japan’s resolve for nuclear non-proliferation and disarmament by announcing ‘11 Benchmarks for Global Nuclear Disarmament’.  It was even reported that Japanese Prime Minister Taro Aso, deeply impressed by Obama’s speech which mentioned an American ‘moral responsibility’, was prepared to send a personal letter to President Obama in order to express Japan’s strong commitment to the US initiative for non-proliferation and disarmament. 
At the same time, however, it can be also expected that Japan’s commitment to nuclear disarmament as a global agenda will occasionally be challenged by regional security demands, which call for credible nuclear deterrence by the United States. Indeed, Japanese security experts are already aware of this tension. Given President Obama’s strong initiative for nuclear disarmament, a prominent Japanese security expert recently wrote that:
For obvious reasons, the Japanese are second to none in wishing for the total elimination of nuclear weapons. However, given Japan’s vulnerability to North Korea’s progressing nuclear and missile programs and China’s growing military power, ensuring American commitment to deterring threats from nuclear and other weapons of mass destruction is a matter of prior strategic importance for Tokyo. 
This opinion expresses Japan’s traditional dilemma between its identity as a non-nuclear state and its reliance on US nuclear deterrence.
It is highly unlikely that Japan will immediately change its traditional nuclear strategy, which enables for both a non-nuclear identity and US nuclear deterrence to co-exist. If my prediction is correct, it can be expected that Japanese policymakers will continue to be required to manage the dilemma that inherently exists in Japan’s nuclear policy. Indeed, this dilemma will only become greater as Japanese policymakers perceive greater threats from the region. This is why Japan has a vital interest in the restoration of the six-party talks dialogue, which might lead to the removal of North Korea’s nuclear weapons. Managing regional threats and uncertainty is important not only for enhancing Japanese security, but also for reducing its dependence on US nuclear protection. Such a policy will mitigate the problem of the ‘nuclear dilemma’ in Japanese non-nuclear policy over the long term. This will enable the Japanese government to continue to work towards nuclear non-proliferation and disarmament while maintaining its non-nuclear national identity in the years to come.
 Kurt M. Campbell and Tsuyoshi Sunohara, ‘Japan: Thinking the Unthinkable’, in Campbell, Robert J. Einhorn, and Mitchell B. Reiss, eds., The Nuclear Tipping Point: Why States Reconsider Their Nuclear Choices (Washington, D.C.: Brookings, 2004), Chap. 9, p. 232.
 David Frum, ‘Mutually Assured Disruption’, The New York Times, October 10, 2006.
 See for example, Michael Green, ‘Japan has little appetite for nukes, and that’s good’, The Interpreter, 21 July 2008.
 Other three policies were: promotion of the peaceful use of nuclear energy; efforts toward global nuclear disarmament; and support for the three non-nuclear principles. For more detail, see Akira Kurosaki, Kakuheiki to Nichibei Kankei: Amerika no Kaku Fukakusan Gaiko to Nihon no Sentaku 1960-1976 [Nuclear weapons and US-Japan relations: Non-proliferation policies of the United States and Japan‘s choices, 1960-1976] (Tokyo: Yushisha, 2006), Chap. 5.
 For instance, Kenneth N. Waltz, ‘The Emerging Structure of International Politics’, International Security 18, no. 2 (fall 1993).
 Anthony Difillippo, Japan’s Nuclear Disarmament Policy and the U.S. Security Umbrella (Palagrave Macmillan, 2006), p.4.
 Mike M. Mochizuki, ‘Japan Tests the Nuclear Taboo’, Nonproliferation Review, Vol. 14, No. 2, July 2007, p.307.
 ‘Nihon no Kaku Hoyuu, Kokueki ni Soguwazu, Beoicho ga Naibu Hokokusho’, Asahi Shimbun, February 19, 2009
 Llewelyn Hughes, ‘Why Japan Will not Go Nuclear (Yet): International and Domestic Constraints on the Nuclearization of Japan’, International Security, Vol. 31, No. 4 (Spring 2007), pp. 89-90.
 Asahi Shinbun, 10 April, 2009.
 See Ministry of Foreign Affairs of Japan, Japan’s Disarmament and Non-Proliferation Policy (Fourth Edition, 2008,) p.38.
 NHK Special (A Japanese TV program), ‘Koushite “Kaku” wa Mochikomareta: Kubo Orisukani no Himitsu’ [This was how Nuclear Weapons were brought into Japan: The Secret of USS Aircraft Oriskany], broadcasted on 9 November, 2008.
 Katsuhisa Furukawa, ‘Nuclear Option, Arms Control, and Extended Deterrence: In Search of a New Framework for Japan’s Nuclear Policy’, in Benjamin L. Self and Jeffrey W. Thompson eds., Japan’s Nuclear Option: Security, Politics, and Policy in the 21st Century (Washington, DC: Henry L. Stimson Center, 2003), Chap. 5, p.120.
 Statement by Mr. Hirofumi Nakasone, Minister for Foreign Affairs of Japan, ‘Conditions towards Zero: 11 Benchmarks for Global Nuclear Disarmament’, April 27, 2009.
 Yukio Satoh, ‘Reinforcing American Extended Deterrence for Japan: An Essential Step for Nuclear Disarmament’, AJISS-Commentary, No. 57, February 2009, 2 [PDF, 208 Kb].
About the author
Satake Tomohiko is a PhD candidate in the Department of International Relations at the Australian National University. Email: firstname.lastname@example.org
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