Japanese Nuclear Decision-Making
Japan’s continued non-nuclear status seems rather puzzling. With high levels of economic, scientific, and technological development, and a sophisticated nuclear energy program, including a plutonium-based fuel cycle, Japan certainly has the means to develop a nuclear weapons program. And bordered by nuclear-armed neighbors with which it has had armed conflicts, Japan also has the motive to acquire nuclear weapons. “Japan lives in a dangerous neighborhood,” as one senior U.S. Japan expert notes, especially in light of the continuing North Korean nuclear crisis.1 As noted in chapter 1, although one can argue that not seeking nuclear weapons may result from having had such weapons dropped on its territory, one can also argue that acquiring nuclear weapons and second-strike capability is the way to avoid recurrence of that tragedy.
Japan’s non-nuclear status is not due to a lack of debate about it. Since the 1950s, Japanese leadership has considered the nuclear question several times. But for almost forty years, Japanese decision-makers have continued to forgo nuclear weapons and affirm the Nuclear Nonproliferation Treaty. The question for policymakers is why. To answer that question, this chapter first examines the social and security environments that undergird Japan’s nuclear stance. Next, the chapter explores the four major periods of nuclear decisionmaking in Japan, before turning to how the international social environment influenced Japanese nuclear forbearance. Finally, findings are compared to the theoretical expectations presented in chapter 1 to see which the evidence supports and in what ways. The case study evidence leads to a conclusion that early on, a mix of realist and constructivist expectations best explains Japanese nuclear forbearance. During that time, many political elites wanted their own nuclear deterrent but chose not to pursue that option for two reasons. First, domestic political opponents, motivated by normative commitments and strengthened in part by the international norm against proliferation, would