Ever since the August 1945 atomic bombings of Hiroshima and Nagasaki, the Japanese people have possessed a strong aversion to the idea of nuclear weapons. Public discussion of developing nuclear weapons has been practically nonexistent, and politicians have been chastised for mentioning the topic: As recently as 1999, Japan's vice defense minister resigned after receiving overwhelming criticism for suggesting that Japan should arm itself with nuclear weapons. And despite mastering the complete nuclear fuel cycle--thus, possessing the necessary nuclear technology and expertise to develop nuclear weapons--and maintaining complicated relationships with growing and unstable neighbors such as China, Tokyo has rejected even considering nuclear weapons. More largely, this "nuclear allergy" has existed alongside a rather pacifist society that has highly constrained itself militarily and politically following World War II.
Yet, in recent years, Japan has sought to become a more "normal" country--especially involving matters of defense and diplomacy, where Tokyo is transitioning from pacifism to assertiveness. In many ways, the nation is attempting to come out from the shadow of World War II. Growing nationalism has led Japan to take less apologetic stances in regards to its history and neighbors--evidenced by former Prime Minister Junichiro Koizumi's visits to the Yasukuni shrine honoring the country's war dead, Japanese strikes on North Korean spy vessels, and continued controversies over distorted portrayals of World War II in Japanese history textbooks. Further, Japan has shown more interest in becoming a regional leader and global player--even expanding its military capability, often with encouragement from the United States. And most surprisingly, the attitude toward nuclear weapons has begun to change.
The attitude shift is evident in the growing prevalence and acceptance of the subject in public discourse. High-level Japanese officials such as current Prime Minister Yasuo Fukuda and his predecessor Shinzo Abe have made several open statements in recent years regarding the possibility of developing nuclear weapons, the need for deterrence in the region, and the nuclear threat presented by Japan's neighbors. As cabinet secretary for the Koizumi administration, Fukuda stated, "In the face of calls to amend the Constitution, amendment of the [three non-nuclear] principles is also possible." During his administration, Abe commented that it wouldn't violate Japan's pacifist constitution to acquire nuclear weapons for defensive purposes. In addition, the policy chief of the Liberal Democratic party has called for "active discussions" of possible nuclear weapons development. Just a few years ago, breaching these subjects openly would have been unpopular and near political suicide, but the Japanese public is now less condemning. Not surprisingly then, nationalist parties that advocate for a nuclear weapons capability are gaining popularity and traction in Japanese politics.
While these developments mostly encompass asserting the rights to debate nuclear options rather than debating the options themselves, they represent a major shift. Actual consideration of nuclear weapons is still a remote and unpopular idea, but mentioning nuclear options is no longer off limits.
In addition to increased public and political references, a generational attitude shift seems to be occurring. In interviews I conducted last fall in Tokyo, several Japanese officials, academics, and nuclear experts thought that younger generations have less of a nuclear allergy than previous generations--especially as memories of Hiroshima and Nagasaki become more distant. While many still felt that strong opposition remains, they believe that younger cohorts cannot remember or directly see the effects of the bombings since they gather that history secondhand, which makes it less personal and emotive. Because of this, they're less afraid of the topic and potential consequences. Overall, the population continues to exhibit strong negative attitudes toward nuclear weapons, and younger generations are still much more adverse to nuclear weapons than populations in most other countries. But the degree of negativity seems to be waning. This isn't unreasonable or unexpected, but it's a gradual shift that's affecting the country's overall nuclear stance.
There is some historical precedent. In both the mid-1960s--when China acquired nuclear weapons--and again in the mid-1990s--following the 1994 North Korean nuclear crisis--the Japanese expressed less aversion to nuclear weapons. The current shift in attitude could simply be a reaction to China's burgeoning role in the region and North Korea's continued reluctance to surrender its nuclear weapons, and public opinion could eventually swing back to a more anti-nuclear stance. But given the generational divide, firsthand aversion is likely to fade for good. Plus, the current change has been building for years and seems more widespread in the population than past reassessments. In addition, just as Japan wants to put its early twentieth-century transgressions behind it, Tokyo may also begin to move beyond its own victimization in the coming years. And it's possible that the regional security situation might become untenable enough that Japan will permanently move away from its pacifist nature. Already, the shift in defensive and diplomatic attitudes is changing in a parallel fashion, making a swing back to full pacifism unlikely.
All that said, by no means is Japan on the road to nuclear weapons development--or even considering it as a serious option. Technically speaking, Japan has several huge constraints to nuclear weapons development--see "Preventing Nuclear Proliferation Chain Reactions: Japan, South Korea, and Egypt" and "Japan's Nuclear Future: Policy Debate, Prospects, and U.S. Interests."
So why should the world be concerned about Japan's fading nuclear allergy? Because Tokyo's attitude toward nuclear weapons is incredibly important to Japan's neighbors and the nonproliferation regime, meaning subtle changes in its attitude could carry serious security consequences for both.
Historically, Japan has maintained complicated relations with many of its neighbors--specifically China, North Korea, and South Korea. While functional relationships do exist, deep mistrust and suspicions persist, creating a paranoid security environment where an innocuous change from an outside perspective sets off alarm bells in the region. So what may seem like a natural shift in Japan's nuclear attitudes may be a destabilizing change for those less trustful and less objective. Therefore, if discussing nuclear weapons becomes more acceptable in Japan, China and the Koreas might perceive this as a dangerous development and use it as an excuse to increase their military capabilities--nuclear or otherwise.
In terms of the teetering nonproliferation regime, a change in Japan's attitude toward nuclear weapons would be a serious blow. To date, Tokyo has been a foremost advocate of the Nuclear Non-Proliferation Treaty, campaigning against proliferation and rejecting the idea of developing nuclear weapons despite possessing the best nuclear capability of any non-nuclear weapon state and having two nuclear weapon states near its borders. The binding nature of international agreements relies on such attention and support from its signatories. So although Japan may never violate the treaty, if Tokyo is perceived as being less supportive as it opens up domestically on the nuclear issue, the effect on NPT morale could be dire, which speaks directly to the NPT's current vulnerability. Some element of the changing attitude toward nuclear weapons in Japan must be due to discomfort with the status quo and a security need that the NPT or the country's other security partnerships isn't satisfying. Therefore, a disturbing factor of Japan's nuclear normalization is what it may symbolize for the NPT overall.
Now, the difficult question: How should the nonproliferation regime and global community manage this nuclear normalization? Since it's nearly impossible and a bit unfair to stop natural attitude change in a country, containing the negative effects requires subtle but conscious efforts. Some strategies include:
Japan is only one nation in the international community, and its nuclear weapons acquisition remains unlikely--despite the internal shift in nuclear attitudes. But nonetheless, how Japanese attitudes evolve is vital for nonproliferation because of the country's history, location, and prior advocacy against nuclear weapons. Recognizing this fact is critical to predicting the potential problems that may arise from such change. The United States and others should not ignore this shift, but do what it can to minimize the consequences.