East Asia Nuclear Policy Project
Morton H. Halperin, The Nuclear Dimension of the U.S.-Japan Alliance

Section 4, "Japanese Nuclear Options"


Japanese Nuclear Options

If these are the basic choices facing the United States, what are the options for Japan? For the purposes of this initial discussion, I leave aside the question of political feasibility in Japan in order to focus on how U.S. policy choices on nuclear weapons and on Korean unification would affect the domestic political climate in Japan and the views of Japanese leaders on what nuclear posture it should adopt. Japanese nuclear options thus include: 1) maintaining the status quo, 2) taking a leadership role in the world to stigmatize nuclear weapons, and 3) nuclear armament.19

1. Status Quo

Widespread revulsion against nuclear weapons in Japan in response to the destruction of Hiroshima and Nagasaki has forced the Japanese government to announce the three non-nuclear principles that Japan "will not manufacture or possess nuclear weapons or allow their introduction into" Japan and that Japan will adhere to the NPT and the CTBT.20 In its rhetoric, Japan is in the forefront of the effort to eliminate nuclear weapons. It has consistently refused to allow the United States to store nuclear weapons on its territory and successfully negotiated in 1972 the withdrawal of nuclear weapons from Okinawa in 1972 prior to reversion-albeit with a secret pledge by Prime Minister Sato to President Nixon that Japan would permit their return in a dire emergency.21

At the same time, Japanese governments have done what was politically possible to support U.S. nuclear policy while quietly putting Japan into a position to be to able to quickly develop nuclear weapons and sophisticated missile delivery systems should a consensus develop in Japan that this needed to be done. 22 Specifically, Japan's cooperation with the United States includes support for U.S. positions on nuclear issues such as the CTBT and a refusal to join informal international coalitions seeking to press for more vigorous steps toward the elimination of nuclear weapons. Documents recently released by the U.S. government furthermore demonstrate that the Japanese government acquiesced to the U.S. practice of having U.S. ships with nuclear weapons call at Japanese ports.23 Yet while it insists that it is determined not to develop nuclear weapons, Japan has a peaceful nuclear power program that generates weapons-grade plutonium, and it also has a space exploration program; many believe that there are Japanese officials who know exactly how to turn these activities into a program that produces nuclear weapons mated to effective delivery systems,24 although there is disagreement about how quickly Japan could have a truly functional nuclear force. However, it remains true that other than the NPT, Japan, unlike Germany, has not entered into any international agreements that commit it to abstaining from developing nuclear weapons.

2. Stigmatizing Nuclear Weapons

Japan could clearly do much more to reinforce its own commitment to not developing nuclear weapons and to taking a lead in moving the world toward the elimination of nuclear weapons.

Under the option of stigmatizing nuclear weapons, Japan would restructure its peaceful nuclear power program so that it does not produce weapons-grade plutonium. Existing stocks of plutonium would be processed in Japan under effective international safeguards. Furthermore, Japan would make its nuclear power and missile programs much more transparent and take steps to make it harder to channel them into a nuclear weapons program. Japan would also take the lead in negotiating a nuclear weapons free zone in Northeast Asia that would commit Japan to neither develop nuclear weapons nor permit them to be deployed on Japanese territory.25 In addition, Japan would rely on the promise of the five nuclear weapons states to not threaten to use nuclear weapons against states in the nuclear free zone and to respond if any state made such a threat. The U.S.-Japan security treaty would remain in effect with its residual commitment by the United States to respond appropriately to any threats against Japan.

Finally, Japan would join other non-nuclear states in pressing for more substantial nuclear disarmament by the nuclear weapons states and would urge the United States to negotiate a bilateral no-first use agreement with China and with Russia, at least in East Asia.

3. Nuclear Armament

Japan's third option is to renounce the NPT and become a nuclear weapons state. It is now difficult to imagine the circumstances under which any Japanese government would pursue nuclear armament, but it is not inconceivable.26 More important, current U.S. policy is justified in no small part by the argument that the United States is doing what is necessary to prevent Japan from going nuclear.27 Moreover, Japan's development of nuclear weapons would certainly signal and accelerate the collapse of the NPT process. No one should take for granted the Japanese commitment over the long run to refrain from developing nuclear weapons.

Many Japanese concerned with international affairs have long chaffed under the U.S. alliance, longing to end the treaty and reassert Japan's role as an independent great power. They have been prevented from implementing such a policy by the recognition that barring major changes in the world situation, the Japanese people would not tolerate such action. Moreover, they recognize that the United States and other states in the region would react very negatively to such a step.

However, one major impediment to a Japanese independent nuclear posture was removed with the collapse of the Soviet Union. Japanese leaders had recognized that they could not match the very large nuclear forces of the Soviet Union; now, they believe that over time, Japan could match the nuclear forces of Russia and China-neither of which can spend significantly more than Japan on nuclear forces. In fact, most analysts expect the Russian nuclear force to be reduced far below the levels permitted by the START agreements with the next ten years.

As the cold war came to an end, some Japanese leaders appeared to give serious consideration to ending the alliance with the United States and to developing an independent Japanese role in Asia, including the development of an independent nuclear capability.28 A consensus rejecting this option has now reemerged in Japan. However, Japan leaders will still carefully assess the international situation, including China's relations with Japan and with the United States, in particular. A close Sino-American relation could lead Japan to question the continued credibility of U.S. security guarantees against China. Alternatively, a withdrawal of U.S. power from Asia, coupled with the continuing growth of Chinese military (including nuclear) capability, could have the same result.

The obvious question raised by the discussion of U.S. and Japanese nuclear policy options is their impact on each other. Is Japan more likely to go nuclear if the United States chooses to stigmatize nuclear weapons or if the United States increases its reliance on nuclear weapons? There is substantial disagreement on this question, rooted in a general difference about the relation of U.S. nuclear policy and efforts to slow nuclear proliferation around the world.

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19 For a discussion of the major positions in current Japanese discourse on the country's proper role -especially with regard to nuclear weapons - in the post-cold war era, see Mike M. Mochizuki, "Japanese Security Policy," in The U.S.-Japan Security Alliance in the 21st Century (New York: Council on Foreign Relations, 1997): 26-42. Back

20 Prime Minister Eisaku Sato made this pledge - known as the Three Non-Nuclear Principles - on February 5, 1968, after the deployment of a U.S. carrier from a Japanese port in retaliation against the capture of a spy ship by the North Korea. The notion was formalized by the Japanese Diet on November 24, 1971. Back

21 Agreed Minute to Joint Communique of United States President Nixon and Japanese Prime Minister Sato Issued on November 21, 1969, Top Secret, Washington, DC, two pages. See the discussion of this issue in the memoirs of Kei Wakeizumi. (English translation on file in the author's office.) Back

22 Prime Minister Sato secretly commissioned a study to examine whether it was possible and desirable to develop independent nuclear forces. It concluded that although there were no technical impediments to doing so, developing nuclear weapons would prove too costly. See "Nuclear Armament Possible But Unrealistic: Secret Reports," Asahi, November 13, 1994, pp.1. Back

23 According to NSSM 5 - Japan, Secret, U.S. National Security Council (spring 1969): 25, "Japan now acquiesces in transit by naval vessels armed with nuclear weapon. This right would extend automatically to Okinawa. (This is sensitive and closely held information)."; also see Masashi Iiyama, "U.S. Report: Japan Allowed N-Arms in Territorial Waters," The Daily Yomiuri (15 May 1997): 2.Back

24 For example, Prime Minister Tsutomu Hata admitted to reporters that "it's certainly the case that Japan has the capability to possess nuclear weapons but has not made them." Kyodo News Service, Tokyo (17 June 1974). Back

25 For details on such a nuclear-free zone, see Harrison, Japan's Nuclear Future: 27-8, 38-9. Back

26 To read of circumstances under which Japan could possibly go nuclear, see Harrison, Japan's Nuclear Future: 33-4. Back

27 "...in the eyes of the anti-nuclear majority [in Japan], the U.S. nuclear umbrella has a more immutable, transcendent value precisely because it provides a rationale for keeping Japan non-nuclear," Harrison, Japan's Nuclear Future: 25. Back

28 Harrison, Japan's Nuclear Future: 15-8. Back


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