Ever since the end of the Cold War, both policymakers: and academics alike have proposed and advocated varied versions of a multilateral security order in Northeast Asia. Given the global trend toward such security management, the lack of progress toward a multilateral security mechanism in Northeast Asia has puzzled many observers. This paper seeks to highlight two of the overarching, yet often overlooked, factors inhibiting the development of security structures in Northeast Asia. The first is that the transitional nature of the current order is preventing the major powers from committing to a new security arrangement and cooperative measures, in fear of another power obtaining the larger share of the gains from such an endeavor. Second, the fundamental geopolitical interests of the major powers in the region in general, and with the Sino-American relations in particular, simply do not provide a fertile foundation for multilateral efforts to flourish. The U.S. geopolitical interest in Northeast Asia is to prevent the rise of a hegemon, and the complexity of the situation arises both from China's aspirations, as well as its actual and latent power. This is partially why the current post-Cold War era is being prolonged, as well as having such a fluid character. Much will depend on how this relationship is managed. In fact, the manner in which the characteristics of the transitional post-Cold War period evolve will largely be sculpted by the future of Sino-American relations.