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understanding Japanese norms and identity—issues neglected by realist or liberal theories—is
essential for understanding the security policy of postwar Japan, and that this case thus
powerfully demonstrates the salience of constructivist theory in the study of international
politics.
To what extent has Japanese security policy been constrained by domestic norms and
antimilitarism? How does the impact of domestic factors and norms compare to the effect of the
external security environment? What theories best explain the past half-century of Japanese
security policy, and what should we expect from Japan in the future?
In this paper I make three central arguments. First, the debate about the roots of Japanese
security policy suffers from widespread misunderstanding about an important aspect of that
policy: specifically, the level of Japanese military power. Scholars have either neglected to
measure Japanese military power or have measured it superficially, fueling the misconception of
Japan as “a military pygmy.” Japan is no military pygmy; since the late 1970s Japan has
transformed its military from a second-rate force to one of the world’s leading military powers.
Second, constructivist theories—predicting that domestic antimilitarism will block major
changes in Japan’s security policy—cannot account for this dramatic transformation. Third, the
course of Japanese post-World War II security policy—both the period of meager defense effort
and the period of vigorous military buildup—is consistent with a realist strategy of “free-riding.”
This analysis has implications for international relations theory and the future of Japanese
security policy. Constructivist analyses have convinced many people that Japan is an outlier or
exception to the way states “should” behave under a realist framework. Constructivist scholars
persuasively illustrate the existence of antimilitarist sentiment in Japan, but as this paper shows,
such sentiments have not prevented Japan from rebuilding its ruined World War II military into
Convention