Making Sense of Asia's Crowded Space Alice D. Ba (bio) Asia has become a crowded space. A region once distinguished by the near absence of cooperative security mechanisms is now distinguished by the opposite. Indeed, once upon a time, this was a region where the only cooperative frameworks purposed for regional security were (1) the bilateral alliances between the United States and a select few regional states and (2) the Association of Southeast Asian Nations (ASEAN), which until the 1990s did not even encompass all the subregion's states. In contrast, the region today consists of a mix of overlapping, crosscutting security frameworks of varying shapes and sizes. Andrew Yeo poses two questions in Asia's Regional Architecture: Alliances and Institutions in the Pacific Century, his recent contribution to the debates about East Asian security. The first is how we explain "the robustness of U.S. bilateral alliances with the rapid proliferation of multilateral institutions in the region" (p. 4). The second is, broadly speaking, what Asia's different security arrangements constitute in toto. There is much to recommend about his discussion. I would emphasize two points, in particular. The first is the "historical institutionalist" perspective the book brings to a policy and analytical space that tends to reduce most outcomes to "strategy," especially the geopolitical and functional challenges faced by states. As Yeo argues, the historical institutionalist approach provides ways to highlight continuity, not just change, as well as the means to capture the complex mix of threat perceptions, ideas, institutions, and domestic politics that go into the construction of elite consensus and, in turn, what he and some others call Asia's regional architecture. The second is his effort to offer a framework that accounts for both the U.S. alliance and multistate institutional dimensions of Asian security. In both instances, the book offers ways to bridge existing accounts that tend to be bifurcated between, on the one hand, those who focus on more conventional (i.e., realist) security drivers associated with traditional security frameworks like U.S. alliances and, on the other hand, those who focus on Asia's regional multilateral endeavors, especially their liberal and sociological drivers. This is important because to consider one without the other is not just to offer an incomplete picture of Asian security but [End Page 131] also, arguably, to miss something even more fundamental going on in the region's international politics. A more accurate picture of Asia consequently demands attention to U.S. bilateral alliances alongside the dramatic growth of nonalliance, multistate arrangements. Andrew Yeo's book thus offers a more complete account than most. Yet, I do have questions. In the spirit of discussion, let me raise two. The first concerns the historical institutionalist approach. In a critical respect, this is the main value the book adds, given that previous studies have detailed similar empirics, processes, and logics of layering associated with Asia's institutions and alliances. One of historical institutionalism's more important insights is the way that past commitments (e.g., cognitive, material, institutional, and policy) bear on conceptualizations of interests (individual and collective), the realm of possible options, and, in turn, the choices made. What is, at times, less clear in the discussion under review, however, is what is doing the work. For example, historical institutionalist approaches highlight the effects of "lock-in" and "feedback" effects associated with particular institutional-ecological contexts, but the processes and mechanisms through which that happens in the cases presented by Yeo are often left underspecified beyond the need to be "cognizant" of the security arrangements created earlier. Part of the challenge is one of scope. Yeo's book is inclusive of nearly all of Asia's actors and a wide range of diverse arrangements—from U.S. alliances to six-party talks to China-Japan-Korea trilateralism to ASEAN configurations. I appreciate the author's attempt. It is very difficult to highlight how past commitments constrain calculations and conclusions in each case over time and across actors without closer examination of either the international or domestic negotiation processes or of their accumulating lock-in processes that, in historical institutionalist accounts, bias one outcome over another. This is, again...