Given Richard J. Samuels's stature in the fields of Japanese politics and foreign policy—each of his last three books is virtually required reading for specialists—there is little point in discussing the virtues of his newest work, for those audiences or for those with a broader interest in East Asian international relations. Most students of these subjects will already have a highlighted copy on their shelves or will feel embarrassed about not yet having read it. In examining the emergence of a new grand strategy for Tokyo, Securing Japan has many of the merits that have made Samuels's earlier studies so important: extraordinarily detailed research findings, previously unexplored avenues that only in retrospect seem self-evidently important, a subtle take on the mutually constitutive nature of ideas and self-interest, and a timeliness that almost seems at odds with the density of the historical material covered.

Samuels divides the book into three sections: a two-chapter examination of the history of strategic thought and security policy in Japan, then three chapters on the sources and character of policy change since the end of the Cold War, and finally two chapters dealing with international threats to Japan, as well as their utility to and management by Japanese security officials. As he acknowledges, policy change in Tokyo seems highly overdetermined. Pick your reason: a rising China; increasing demands for militarization from the United States; an almost cartoonishly villainous North Korean regime armed with its menacing, if imprecise, Nodong missiles; ideological change in Japanese society; savvy public relations tactics by the Self-Defense Forces, wielding comic-book mascots like the disconcertingly named “Prince Pickles”; displacement of older political leaders whose focus on mercantilist economic growth had been discredited by the long recession; the rise to power of a charismatic hawk, Junichiro Koizumi, who helped to redesign institutions allowing the cabinet to override cautious Ministry of Foreign Affairs diplomats; and so on. Samuels deals with all of these and does not single out any as being the “magic bullet” that explains change.

The author does, however, argue that the policies have to be understood as the outcomes of political debates, and that they were not preordained simply by external events or by some kind of essential continuity or consensus in Japanese politics. The War on Terror, Chinese industrial development, and transnational defense production schemes, particularly among European powers, all matter because of the ways in which they are filtered through the particular lenses of relevant Japanese actors, including politicians, defense contractors, military strategists, and policy intellectuals. To make the case, Samuels traces different strands of thought on Japanese security, showing that grand strategies have evolved not out of simple cost–benefit calculations but, rather, from areas of overlap and agreement among actors with, in many ways, divergent ideas and views. Just as the postwar “Yoshida Doctrine”—promotion of economic growth while, in essence, free riding on American security guarantees—resulted in part from Prime Minister Yoshida's outmaneuvering hawkish competitors and in part from marriages of convenience with left-leaning pacifists, the emerging “Goldilocks consensus” (not too militarily active, not too dependent on American protection, but instead “just right”) is itself the outcome of debate, negotiation, and sometimes odd pairings among the political Left and Right.

One might argue that everyone ought to be concerned about East Asian security politics; after all, as Samuels notes, the likelihood of armed superpower conflict in the coming years seems nowhere higher than it does in this neck of the woods, with a rising China, an assertive Japan, contests over resources, and the possible diminution of American security guarantees. This book is, whatever its other qualities, an excellent primer on the history of Japanese security politics and on the emerging security dilemmas of East Asia.

Still, not everyone will be immediately drawn to a book about Japanese military force, and the book's broader potential contributions may be less visible than they ought to be. Because he focuses so tightly on his subject—indeed, his reading on Japanese defense seems nearly exhaustive in both English and Japanese—Samuels does not explicitly tie his work to conventional theories of politics except to engage critically both realism and, to a degree, constructivism in security studies without committing himself to either. This will not matter for the book's viability among the students and policymakers who deal with Asia, but I wish that he had followed some of the potential theoretical strands more closely. Doing so might have clarified some of the more complicated connections in his later chapters (while potentially forcing some sacrifices in coverage) and would have also alerted potential readers to its broader contributions. For some readers who prefer more deterministic and predictive claims, his argument might seem too open-ended and contingent on the outcome of policy debates that are ad hoc by nature. Yet a more focused theoretical claim, hinging on a discrete independent variable or a singular and easily defined intervening variable, might have streamlined the narrative at the cost of excluding some of Samuels's most surprising findings, including his truly fascinating explorations of the Cabinet Legislation Bureau's long-misunderstood role or of the changing position of Japan's Coast Guard. Both of these are instructive not just for specialists on Japanese politics but also for wider debates about political control over foreign policy and about the nature of paramilitary units.

Additionally, even if Samuels does not himself emphasize them, Securing Japan contains theoretical insights that would be highly relevant to more general debates in political science, including those that have nothing to do with Japan or even the Asian Pacific. Its connection of ideas to policy, particularly if rendered more formally, would make it a welcome complement to the work of Kathryn Sikkink, Emmanuel Adler, and Judith Goldstein and Robert Keohane. And anyone studying anti-Americanism in world politics ought to study Samuels's striking coverage of the place of the United States in Japanese political thought. This is not how we conventionally think of anti-Americanism—there is no threat of suicide bombers, boycotts, or attack—but the author's attention to the shape of the American bogeyman across different parts of the Japanese political spectrum would greatly enrich discussions that focus too often on only the more visible manifestations of resistance to an imperial United States.

I am making this case for more attention to theory not to identify flaws in the book but, rather, to point out its less obvious contributions. Taken on its own terms, this is a first-rate piece of work, and will certainly merit the wide readership it is sure to enjoy among Japan specialists and students of East Asian international relations. But I hope it is read more extensively than that. At the very least, it is a well-written, rich, concise, and even entertaining introduction to a topic that is probably far more important to most of our lives than many would immediately recognize. Even more, its insights are of wide relevance to our discussions of power, ideology, and the role of the United States in a world that does not know quite what to make of it.